October 2024 - Linux-stable-mirror

FAILED: patch "[PATCH] lsm: add the inode_free_security_rcu() LSM implementation" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 63dff3e48871b0583be5032ff8fb7260c349a18c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100132-kung-gibberish-1f5b@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") 4de2f084fbff ("ima: Make it independent from 'integrity' LSM") 75a323e604fc ("evm: Make it independent from 'integrity' LSM") 923831117611 ("evm: Move to LSM infrastructure") 84594c9ecdca ("ima: Move IMA-Appraisal to LSM infrastructure") cd3cec0a02c7 ("ima: Move to LSM infrastructure") 06cca5110774 ("integrity: Move integrity_kernel_module_request() to IMA") b8d997032a46 ("security: Introduce key_post_create_or_update hook") 2d705d802414 ("security: Introduce inode_post_remove_acl hook") 8b9d0b825c65 ("security: Introduce inode_post_set_acl hook") a7811e34d100 ("security: Introduce inode_post_create_tmpfile hook") f09068b5a114 ("security: Introduce file_release hook") 8f46ff5767b0 ("security: Introduce file_post_open hook") dae52cbf5887 ("security: Introduce inode_post_removexattr hook") 77fa6f314f03 ("security: Introduce inode_post_setattr hook") 314a8dc728d0 ("security: Align inode_setattr hook definition with EVM") 779cb1947e27 ("evm: Align evm_inode_post_setxattr() definition with LSM infrastructure") 2b6a4054f8c2 ("evm: Align evm_inode_setxattr() definition with LSM infrastructure") 784111d0093e ("evm: Align evm_inode_post_setattr() definition with LSM infrastructure") fec5f85e468d ("ima: Align ima_post_read_file() definition with LSM infrastructure") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 63dff3e48871b0583be5032ff8fb7260c349a18c Mon Sep 17 00:00:00 2001 From: Paul Moore <paul(a)paul-moore.com> Date: Tue, 9 Jul 2024 19:43:06 -0400 Subject: [PATCH] lsm: add the inode_free_security_rcu() LSM implementation hook The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable(a)vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore <paul(a)paul-moore.com> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 63e2656d1d56..520730fe2d94 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -114,6 +114,7 @@ LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, unsigned int obj_type) LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security_rcu, void *inode_security) LSM_HOOK(int, -EOPNOTSUPP, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c51e24d24d1e..3c323ca213d4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -223,7 +223,7 @@ static inline void ima_inode_set_iint(const struct inode *inode, struct ima_iint_cache *ima_iint_find(struct inode *inode); struct ima_iint_cache *ima_inode_get(struct inode *inode); -void ima_inode_free(struct inode *inode); +void ima_inode_free_rcu(void *inode_security); void __init ima_iintcache_init(void); extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index e23412a2c56b..00b249101f98 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -109,22 +109,18 @@ struct ima_iint_cache *ima_inode_get(struct inode *inode) } /** - * ima_inode_free - Called on inode free - * @inode: Pointer to the inode + * ima_inode_free_rcu - Called to free an inode via a RCU callback + * @inode_security: The inode->i_security pointer * - * Free the iint associated with an inode. + * Free the IMA data associated with an inode. */ -void ima_inode_free(struct inode *inode) +void ima_inode_free_rcu(void *inode_security) { - struct ima_iint_cache *iint; + struct ima_iint_cache **iint_p = inode_security + ima_blob_sizes.lbs_inode; - if (!IS_IMA(inode)) - return; - - iint = ima_iint_find(inode); - ima_inode_set_iint(inode, NULL); - - ima_iint_free(iint); + /* *iint_p should be NULL if !IS_IMA(inode) */ + if (*iint_p) + ima_iint_free(*iint_p); } static void ima_iint_init_once(void *foo) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f04f43af651c..5b3394864b21 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1193,7 +1193,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = { #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), #endif - LSM_HOOK_INIT(inode_free_security, ima_inode_free), + LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), }; static const struct lsm_id ima_lsmid = { diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 7877a64cc6b8..0804f76a67be 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1207,13 +1207,16 @@ static int current_check_refer_path(struct dentry *const old_dentry, /* Inode hooks */ -static void hook_inode_free_security(struct inode *const inode) +static void hook_inode_free_security_rcu(void *inode_security) { + struct landlock_inode_security *inode_sec; + /* * All inodes must already have been untied from their object by * release_inode() or hook_sb_delete(). */ - WARN_ON_ONCE(landlock_inode(inode)->object); + inode_sec = inode_security + landlock_blob_sizes.lbs_inode; + WARN_ON_ONCE(inode_sec->object); } /* Super-block hooks */ @@ -1637,7 +1640,7 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, } static struct security_hook_list landlock_hooks[] __ro_after_init = { - LSM_HOOK_INIT(inode_free_security, hook_inode_free_security), + LSM_HOOK_INIT(inode_free_security_rcu, hook_inode_free_security_rcu), LSM_HOOK_INIT(sb_delete, hook_sb_delete), LSM_HOOK_INIT(sb_mount, hook_sb_mount), diff --git a/security/security.c b/security/security.c index b316e6586be2..611d3c124ba6 100644 --- a/security/security.c +++ b/security/security.c @@ -1609,9 +1609,8 @@ int security_inode_alloc(struct inode *inode) static void inode_free_by_rcu(struct rcu_head *head) { - /* - * The rcu head is at the start of the inode blob - */ + /* The rcu head is at the start of the inode blob */ + call_void_hook(inode_free_security_rcu, head); kmem_cache_free(lsm_inode_cache, head); } @@ -1619,23 +1618,24 @@ static void inode_free_by_rcu(struct rcu_head *head) * security_inode_free() - Free an inode's LSM blob * @inode: the inode * - * Deallocate the inode security structure and set @inode->i_security to NULL. + * Release any LSM resources associated with @inode, although due to the + * inode's RCU protections it is possible that the resources will not be + * fully released until after the current RCU grace period has elapsed. + * + * It is important for LSMs to note that despite being present in a call to + * security_inode_free(), @inode may still be referenced in a VFS path walk + * and calls to security_inode_permission() may be made during, or after, + * a call to security_inode_free(). For this reason the inode->i_security + * field is released via a call_rcu() callback and any LSMs which need to + * retain inode state for use in security_inode_permission() should only + * release that state in the inode_free_security_rcu() LSM hook callback. */ void security_inode_free(struct inode *inode) { call_void_hook(inode_free_security, inode); - /* - * The inode may still be referenced in a path walk and - * a call to security_inode_permission() can be made - * after inode_free_security() is called. Ideally, the VFS - * wouldn't do this, but fixing that is a much harder - * job. For now, simply free the i_security via RCU, and - * leave the current inode->i_security pointer intact. - * The inode will be freed after the RCU grace period too. - */ - if (inode->i_security) - call_rcu((struct rcu_head *)inode->i_security, - inode_free_by_rcu); + if (!inode->i_security) + return; + call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu); } /**

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FAILED: patch "[PATCH] lsm: add the inode_free_security_rcu() LSM implementation" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 63dff3e48871b0583be5032ff8fb7260c349a18c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100131-concerned-unashamed-5020@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") 4de2f084fbff ("ima: Make it independent from 'integrity' LSM") 75a323e604fc ("evm: Make it independent from 'integrity' LSM") 923831117611 ("evm: Move to LSM infrastructure") 84594c9ecdca ("ima: Move IMA-Appraisal to LSM infrastructure") cd3cec0a02c7 ("ima: Move to LSM infrastructure") 06cca5110774 ("integrity: Move integrity_kernel_module_request() to IMA") b8d997032a46 ("security: Introduce key_post_create_or_update hook") 2d705d802414 ("security: Introduce inode_post_remove_acl hook") 8b9d0b825c65 ("security: Introduce inode_post_set_acl hook") a7811e34d100 ("security: Introduce inode_post_create_tmpfile hook") f09068b5a114 ("security: Introduce file_release hook") 8f46ff5767b0 ("security: Introduce file_post_open hook") dae52cbf5887 ("security: Introduce inode_post_removexattr hook") 77fa6f314f03 ("security: Introduce inode_post_setattr hook") 314a8dc728d0 ("security: Align inode_setattr hook definition with EVM") 779cb1947e27 ("evm: Align evm_inode_post_setxattr() definition with LSM infrastructure") 2b6a4054f8c2 ("evm: Align evm_inode_setxattr() definition with LSM infrastructure") 784111d0093e ("evm: Align evm_inode_post_setattr() definition with LSM infrastructure") fec5f85e468d ("ima: Align ima_post_read_file() definition with LSM infrastructure") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 63dff3e48871b0583be5032ff8fb7260c349a18c Mon Sep 17 00:00:00 2001 From: Paul Moore <paul(a)paul-moore.com> Date: Tue, 9 Jul 2024 19:43:06 -0400 Subject: [PATCH] lsm: add the inode_free_security_rcu() LSM implementation hook The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable(a)vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore <paul(a)paul-moore.com> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 63e2656d1d56..520730fe2d94 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -114,6 +114,7 @@ LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, unsigned int obj_type) LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security_rcu, void *inode_security) LSM_HOOK(int, -EOPNOTSUPP, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c51e24d24d1e..3c323ca213d4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -223,7 +223,7 @@ static inline void ima_inode_set_iint(const struct inode *inode, struct ima_iint_cache *ima_iint_find(struct inode *inode); struct ima_iint_cache *ima_inode_get(struct inode *inode); -void ima_inode_free(struct inode *inode); +void ima_inode_free_rcu(void *inode_security); void __init ima_iintcache_init(void); extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index e23412a2c56b..00b249101f98 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -109,22 +109,18 @@ struct ima_iint_cache *ima_inode_get(struct inode *inode) } /** - * ima_inode_free - Called on inode free - * @inode: Pointer to the inode + * ima_inode_free_rcu - Called to free an inode via a RCU callback + * @inode_security: The inode->i_security pointer * - * Free the iint associated with an inode. + * Free the IMA data associated with an inode. */ -void ima_inode_free(struct inode *inode) +void ima_inode_free_rcu(void *inode_security) { - struct ima_iint_cache *iint; + struct ima_iint_cache **iint_p = inode_security + ima_blob_sizes.lbs_inode; - if (!IS_IMA(inode)) - return; - - iint = ima_iint_find(inode); - ima_inode_set_iint(inode, NULL); - - ima_iint_free(iint); + /* *iint_p should be NULL if !IS_IMA(inode) */ + if (*iint_p) + ima_iint_free(*iint_p); } static void ima_iint_init_once(void *foo) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f04f43af651c..5b3394864b21 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1193,7 +1193,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = { #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), #endif - LSM_HOOK_INIT(inode_free_security, ima_inode_free), + LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), }; static const struct lsm_id ima_lsmid = { diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 7877a64cc6b8..0804f76a67be 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1207,13 +1207,16 @@ static int current_check_refer_path(struct dentry *const old_dentry, /* Inode hooks */ -static void hook_inode_free_security(struct inode *const inode) +static void hook_inode_free_security_rcu(void *inode_security) { + struct landlock_inode_security *inode_sec; + /* * All inodes must already have been untied from their object by * release_inode() or hook_sb_delete(). */ - WARN_ON_ONCE(landlock_inode(inode)->object); + inode_sec = inode_security + landlock_blob_sizes.lbs_inode; + WARN_ON_ONCE(inode_sec->object); } /* Super-block hooks */ @@ -1637,7 +1640,7 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, } static struct security_hook_list landlock_hooks[] __ro_after_init = { - LSM_HOOK_INIT(inode_free_security, hook_inode_free_security), + LSM_HOOK_INIT(inode_free_security_rcu, hook_inode_free_security_rcu), LSM_HOOK_INIT(sb_delete, hook_sb_delete), LSM_HOOK_INIT(sb_mount, hook_sb_mount), diff --git a/security/security.c b/security/security.c index b316e6586be2..611d3c124ba6 100644 --- a/security/security.c +++ b/security/security.c @@ -1609,9 +1609,8 @@ int security_inode_alloc(struct inode *inode) static void inode_free_by_rcu(struct rcu_head *head) { - /* - * The rcu head is at the start of the inode blob - */ + /* The rcu head is at the start of the inode blob */ + call_void_hook(inode_free_security_rcu, head); kmem_cache_free(lsm_inode_cache, head); } @@ -1619,23 +1618,24 @@ static void inode_free_by_rcu(struct rcu_head *head) * security_inode_free() - Free an inode's LSM blob * @inode: the inode * - * Deallocate the inode security structure and set @inode->i_security to NULL. + * Release any LSM resources associated with @inode, although due to the + * inode's RCU protections it is possible that the resources will not be + * fully released until after the current RCU grace period has elapsed. + * + * It is important for LSMs to note that despite being present in a call to + * security_inode_free(), @inode may still be referenced in a VFS path walk + * and calls to security_inode_permission() may be made during, or after, + * a call to security_inode_free(). For this reason the inode->i_security + * field is released via a call_rcu() callback and any LSMs which need to + * retain inode state for use in security_inode_permission() should only + * release that state in the inode_free_security_rcu() LSM hook callback. */ void security_inode_free(struct inode *inode) { call_void_hook(inode_free_security, inode); - /* - * The inode may still be referenced in a path walk and - * a call to security_inode_permission() can be made - * after inode_free_security() is called. Ideally, the VFS - * wouldn't do this, but fixing that is a much harder - * job. For now, simply free the i_security via RCU, and - * leave the current inode->i_security pointer intact. - * The inode will be freed after the RCU grace period too. - */ - if (inode->i_security) - call_rcu((struct rcu_head *)inode->i_security, - inode_free_by_rcu); + if (!inode->i_security) + return; + call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu); } /**

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FAILED: patch "[PATCH] lsm: add the inode_free_security_rcu() LSM implementation" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 63dff3e48871b0583be5032ff8fb7260c349a18c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100130-superior-viewpoint-e91a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") 4de2f084fbff ("ima: Make it independent from 'integrity' LSM") 75a323e604fc ("evm: Make it independent from 'integrity' LSM") 923831117611 ("evm: Move to LSM infrastructure") 84594c9ecdca ("ima: Move IMA-Appraisal to LSM infrastructure") cd3cec0a02c7 ("ima: Move to LSM infrastructure") 06cca5110774 ("integrity: Move integrity_kernel_module_request() to IMA") b8d997032a46 ("security: Introduce key_post_create_or_update hook") 2d705d802414 ("security: Introduce inode_post_remove_acl hook") 8b9d0b825c65 ("security: Introduce inode_post_set_acl hook") a7811e34d100 ("security: Introduce inode_post_create_tmpfile hook") f09068b5a114 ("security: Introduce file_release hook") 8f46ff5767b0 ("security: Introduce file_post_open hook") dae52cbf5887 ("security: Introduce inode_post_removexattr hook") 77fa6f314f03 ("security: Introduce inode_post_setattr hook") 314a8dc728d0 ("security: Align inode_setattr hook definition with EVM") 779cb1947e27 ("evm: Align evm_inode_post_setxattr() definition with LSM infrastructure") 2b6a4054f8c2 ("evm: Align evm_inode_setxattr() definition with LSM infrastructure") 784111d0093e ("evm: Align evm_inode_post_setattr() definition with LSM infrastructure") fec5f85e468d ("ima: Align ima_post_read_file() definition with LSM infrastructure") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 63dff3e48871b0583be5032ff8fb7260c349a18c Mon Sep 17 00:00:00 2001 From: Paul Moore <paul(a)paul-moore.com> Date: Tue, 9 Jul 2024 19:43:06 -0400 Subject: [PATCH] lsm: add the inode_free_security_rcu() LSM implementation hook The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable(a)vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore <paul(a)paul-moore.com> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 63e2656d1d56..520730fe2d94 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -114,6 +114,7 @@ LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, unsigned int obj_type) LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security_rcu, void *inode_security) LSM_HOOK(int, -EOPNOTSUPP, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c51e24d24d1e..3c323ca213d4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -223,7 +223,7 @@ static inline void ima_inode_set_iint(const struct inode *inode, struct ima_iint_cache *ima_iint_find(struct inode *inode); struct ima_iint_cache *ima_inode_get(struct inode *inode); -void ima_inode_free(struct inode *inode); +void ima_inode_free_rcu(void *inode_security); void __init ima_iintcache_init(void); extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index e23412a2c56b..00b249101f98 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -109,22 +109,18 @@ struct ima_iint_cache *ima_inode_get(struct inode *inode) } /** - * ima_inode_free - Called on inode free - * @inode: Pointer to the inode + * ima_inode_free_rcu - Called to free an inode via a RCU callback + * @inode_security: The inode->i_security pointer * - * Free the iint associated with an inode. + * Free the IMA data associated with an inode. */ -void ima_inode_free(struct inode *inode) +void ima_inode_free_rcu(void *inode_security) { - struct ima_iint_cache *iint; + struct ima_iint_cache **iint_p = inode_security + ima_blob_sizes.lbs_inode; - if (!IS_IMA(inode)) - return; - - iint = ima_iint_find(inode); - ima_inode_set_iint(inode, NULL); - - ima_iint_free(iint); + /* *iint_p should be NULL if !IS_IMA(inode) */ + if (*iint_p) + ima_iint_free(*iint_p); } static void ima_iint_init_once(void *foo) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f04f43af651c..5b3394864b21 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1193,7 +1193,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = { #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), #endif - LSM_HOOK_INIT(inode_free_security, ima_inode_free), + LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), }; static const struct lsm_id ima_lsmid = { diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 7877a64cc6b8..0804f76a67be 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1207,13 +1207,16 @@ static int current_check_refer_path(struct dentry *const old_dentry, /* Inode hooks */ -static void hook_inode_free_security(struct inode *const inode) +static void hook_inode_free_security_rcu(void *inode_security) { + struct landlock_inode_security *inode_sec; + /* * All inodes must already have been untied from their object by * release_inode() or hook_sb_delete(). */ - WARN_ON_ONCE(landlock_inode(inode)->object); + inode_sec = inode_security + landlock_blob_sizes.lbs_inode; + WARN_ON_ONCE(inode_sec->object); } /* Super-block hooks */ @@ -1637,7 +1640,7 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, } static struct security_hook_list landlock_hooks[] __ro_after_init = { - LSM_HOOK_INIT(inode_free_security, hook_inode_free_security), + LSM_HOOK_INIT(inode_free_security_rcu, hook_inode_free_security_rcu), LSM_HOOK_INIT(sb_delete, hook_sb_delete), LSM_HOOK_INIT(sb_mount, hook_sb_mount), diff --git a/security/security.c b/security/security.c index b316e6586be2..611d3c124ba6 100644 --- a/security/security.c +++ b/security/security.c @@ -1609,9 +1609,8 @@ int security_inode_alloc(struct inode *inode) static void inode_free_by_rcu(struct rcu_head *head) { - /* - * The rcu head is at the start of the inode blob - */ + /* The rcu head is at the start of the inode blob */ + call_void_hook(inode_free_security_rcu, head); kmem_cache_free(lsm_inode_cache, head); } @@ -1619,23 +1618,24 @@ static void inode_free_by_rcu(struct rcu_head *head) * security_inode_free() - Free an inode's LSM blob * @inode: the inode * - * Deallocate the inode security structure and set @inode->i_security to NULL. + * Release any LSM resources associated with @inode, although due to the + * inode's RCU protections it is possible that the resources will not be + * fully released until after the current RCU grace period has elapsed. + * + * It is important for LSMs to note that despite being present in a call to + * security_inode_free(), @inode may still be referenced in a VFS path walk + * and calls to security_inode_permission() may be made during, or after, + * a call to security_inode_free(). For this reason the inode->i_security + * field is released via a call_rcu() callback and any LSMs which need to + * retain inode state for use in security_inode_permission() should only + * release that state in the inode_free_security_rcu() LSM hook callback. */ void security_inode_free(struct inode *inode) { call_void_hook(inode_free_security, inode); - /* - * The inode may still be referenced in a path walk and - * a call to security_inode_permission() can be made - * after inode_free_security() is called. Ideally, the VFS - * wouldn't do this, but fixing that is a much harder - * job. For now, simply free the i_security via RCU, and - * leave the current inode->i_security pointer intact. - * The inode will be freed after the RCU grace period too. - */ - if (inode->i_security) - call_rcu((struct rcu_head *)inode->i_security, - inode_free_by_rcu); + if (!inode->i_security) + return; + call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu); } /**

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FAILED: patch "[PATCH] lsm: add the inode_free_security_rcu() LSM implementation" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 63dff3e48871b0583be5032ff8fb7260c349a18c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100129-undertook-rebuff-1fdd@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") 4de2f084fbff ("ima: Make it independent from 'integrity' LSM") 75a323e604fc ("evm: Make it independent from 'integrity' LSM") 923831117611 ("evm: Move to LSM infrastructure") 84594c9ecdca ("ima: Move IMA-Appraisal to LSM infrastructure") cd3cec0a02c7 ("ima: Move to LSM infrastructure") 06cca5110774 ("integrity: Move integrity_kernel_module_request() to IMA") b8d997032a46 ("security: Introduce key_post_create_or_update hook") 2d705d802414 ("security: Introduce inode_post_remove_acl hook") 8b9d0b825c65 ("security: Introduce inode_post_set_acl hook") a7811e34d100 ("security: Introduce inode_post_create_tmpfile hook") f09068b5a114 ("security: Introduce file_release hook") 8f46ff5767b0 ("security: Introduce file_post_open hook") dae52cbf5887 ("security: Introduce inode_post_removexattr hook") 77fa6f314f03 ("security: Introduce inode_post_setattr hook") 314a8dc728d0 ("security: Align inode_setattr hook definition with EVM") 779cb1947e27 ("evm: Align evm_inode_post_setxattr() definition with LSM infrastructure") 2b6a4054f8c2 ("evm: Align evm_inode_setxattr() definition with LSM infrastructure") 784111d0093e ("evm: Align evm_inode_post_setattr() definition with LSM infrastructure") fec5f85e468d ("ima: Align ima_post_read_file() definition with LSM infrastructure") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 63dff3e48871b0583be5032ff8fb7260c349a18c Mon Sep 17 00:00:00 2001 From: Paul Moore <paul(a)paul-moore.com> Date: Tue, 9 Jul 2024 19:43:06 -0400 Subject: [PATCH] lsm: add the inode_free_security_rcu() LSM implementation hook The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable(a)vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore <paul(a)paul-moore.com> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 63e2656d1d56..520730fe2d94 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -114,6 +114,7 @@ LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, unsigned int obj_type) LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security_rcu, void *inode_security) LSM_HOOK(int, -EOPNOTSUPP, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c51e24d24d1e..3c323ca213d4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -223,7 +223,7 @@ static inline void ima_inode_set_iint(const struct inode *inode, struct ima_iint_cache *ima_iint_find(struct inode *inode); struct ima_iint_cache *ima_inode_get(struct inode *inode); -void ima_inode_free(struct inode *inode); +void ima_inode_free_rcu(void *inode_security); void __init ima_iintcache_init(void); extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index e23412a2c56b..00b249101f98 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -109,22 +109,18 @@ struct ima_iint_cache *ima_inode_get(struct inode *inode) } /** - * ima_inode_free - Called on inode free - * @inode: Pointer to the inode + * ima_inode_free_rcu - Called to free an inode via a RCU callback + * @inode_security: The inode->i_security pointer * - * Free the iint associated with an inode. + * Free the IMA data associated with an inode. */ -void ima_inode_free(struct inode *inode) +void ima_inode_free_rcu(void *inode_security) { - struct ima_iint_cache *iint; + struct ima_iint_cache **iint_p = inode_security + ima_blob_sizes.lbs_inode; - if (!IS_IMA(inode)) - return; - - iint = ima_iint_find(inode); - ima_inode_set_iint(inode, NULL); - - ima_iint_free(iint); + /* *iint_p should be NULL if !IS_IMA(inode) */ + if (*iint_p) + ima_iint_free(*iint_p); } static void ima_iint_init_once(void *foo) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f04f43af651c..5b3394864b21 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1193,7 +1193,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = { #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), #endif - LSM_HOOK_INIT(inode_free_security, ima_inode_free), + LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), }; static const struct lsm_id ima_lsmid = { diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 7877a64cc6b8..0804f76a67be 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1207,13 +1207,16 @@ static int current_check_refer_path(struct dentry *const old_dentry, /* Inode hooks */ -static void hook_inode_free_security(struct inode *const inode) +static void hook_inode_free_security_rcu(void *inode_security) { + struct landlock_inode_security *inode_sec; + /* * All inodes must already have been untied from their object by * release_inode() or hook_sb_delete(). */ - WARN_ON_ONCE(landlock_inode(inode)->object); + inode_sec = inode_security + landlock_blob_sizes.lbs_inode; + WARN_ON_ONCE(inode_sec->object); } /* Super-block hooks */ @@ -1637,7 +1640,7 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, } static struct security_hook_list landlock_hooks[] __ro_after_init = { - LSM_HOOK_INIT(inode_free_security, hook_inode_free_security), + LSM_HOOK_INIT(inode_free_security_rcu, hook_inode_free_security_rcu), LSM_HOOK_INIT(sb_delete, hook_sb_delete), LSM_HOOK_INIT(sb_mount, hook_sb_mount), diff --git a/security/security.c b/security/security.c index b316e6586be2..611d3c124ba6 100644 --- a/security/security.c +++ b/security/security.c @@ -1609,9 +1609,8 @@ int security_inode_alloc(struct inode *inode) static void inode_free_by_rcu(struct rcu_head *head) { - /* - * The rcu head is at the start of the inode blob - */ + /* The rcu head is at the start of the inode blob */ + call_void_hook(inode_free_security_rcu, head); kmem_cache_free(lsm_inode_cache, head); } @@ -1619,23 +1618,24 @@ static void inode_free_by_rcu(struct rcu_head *head) * security_inode_free() - Free an inode's LSM blob * @inode: the inode * - * Deallocate the inode security structure and set @inode->i_security to NULL. + * Release any LSM resources associated with @inode, although due to the + * inode's RCU protections it is possible that the resources will not be + * fully released until after the current RCU grace period has elapsed. + * + * It is important for LSMs to note that despite being present in a call to + * security_inode_free(), @inode may still be referenced in a VFS path walk + * and calls to security_inode_permission() may be made during, or after, + * a call to security_inode_free(). For this reason the inode->i_security + * field is released via a call_rcu() callback and any LSMs which need to + * retain inode state for use in security_inode_permission() should only + * release that state in the inode_free_security_rcu() LSM hook callback. */ void security_inode_free(struct inode *inode) { call_void_hook(inode_free_security, inode); - /* - * The inode may still be referenced in a path walk and - * a call to security_inode_permission() can be made - * after inode_free_security() is called. Ideally, the VFS - * wouldn't do this, but fixing that is a much harder - * job. For now, simply free the i_security via RCU, and - * leave the current inode->i_security pointer intact. - * The inode will be freed after the RCU grace period too. - */ - if (inode->i_security) - call_rcu((struct rcu_head *)inode->i_security, - inode_free_by_rcu); + if (!inode->i_security) + return; + call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu); } /**

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FAILED: patch "[PATCH] padata: use integer wrap around to prevent deadlock on seq_nr" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 9a22b2812393d93d84358a760c347c21939029a6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100110-smokiness-detract-b410@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 9a22b2812393 ("padata: use integer wrap around to prevent deadlock on seq_nr overflow") 57ddfecc72a6 ("padata: Fix list iterator in padata_do_serial()") f601c725a6ac ("padata: remove padata_parallel_queue") 4611ce224688 ("padata: allocate work structures for parallel jobs from a pool") f1b192b117cd ("padata: initialize earlier") 305dacf77952 ("padata: remove exit routine") bfcdcef8c8e3 ("padata: update documentation") 3facced7aeed ("padata: remove reorder_objects") 91a71d612128 ("padata: remove cpumask change notifier") 894c9ef9780c ("padata: validate cpumask without removed CPU during offline") bbefa1dd6a6d ("crypto: pcrypt - Avoid deadlock by using per-instance padata queues") 07928d9bfc81 ("padata: Remove broken queue flushing") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9a22b2812393d93d84358a760c347c21939029a6 Mon Sep 17 00:00:00 2001 From: VanGiang Nguyen <vangiang.nguyen(a)rohde-schwarz.com> Date: Fri, 9 Aug 2024 06:21:42 +0000 Subject: [PATCH] padata: use integer wrap around to prevent deadlock on seq_nr overflow When submitting more than 2^32 padata objects to padata_do_serial, the current sorting implementation incorrectly sorts padata objects with overflowed seq_nr, causing them to be placed before existing objects in the reorder list. This leads to a deadlock in the serialization process as padata_find_next cannot match padata->seq_nr and pd->processed because the padata instance with overflowed seq_nr will be selected next. To fix this, we use an unsigned integer wrap around to correctly sort padata objects in scenarios with integer overflow. Fixes: bfde23ce200e ("padata: unbind parallel jobs from specific CPUs") Cc: <stable(a)vger.kernel.org> Co-developed-by: Christian Gafert <christian.gafert(a)rohde-schwarz.com> Signed-off-by: Christian Gafert <christian.gafert(a)rohde-schwarz.com> Co-developed-by: Max Ferger <max.ferger(a)rohde-schwarz.com> Signed-off-by: Max Ferger <max.ferger(a)rohde-schwarz.com> Signed-off-by: Van Giang Nguyen <vangiang.nguyen(a)rohde-schwarz.com> Acked-by: Daniel Jordan <daniel.m.jordan(a)oracle.com> Signed-off-by: Herbert Xu <herbert(a)gondor.apana.org.au> diff --git a/kernel/padata.c b/kernel/padata.c index 53f4bc912712..222bccd0c96b 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -404,7 +404,8 @@ void padata_do_serial(struct padata_priv *padata) /* Sort in ascending order of sequence number. */ list_for_each_prev(pos, &reorder->list) { cur = list_entry(pos, struct padata_priv, list); - if (cur->seq_nr < padata->seq_nr) + /* Compare by difference to consider integer wrap around */ + if ((signed int)(cur->seq_nr - padata->seq_nr) < 0) break; } list_add(&padata->list, pos);

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FAILED: patch "[PATCH] cpuidle: riscv-sbi: Use scoped device node handling to fix" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x a309320ddbac6b1583224fcb6bacd424bcf8637f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100154-maternity-snowfield-cbf4@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: a309320ddbac ("cpuidle: riscv-sbi: Use scoped device node handling to fix missing of_node_put") 24760e43c6a6 ("cpuidle: Adjust includes to remove of_device.h") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a309320ddbac6b1583224fcb6bacd424bcf8637f Mon Sep 17 00:00:00 2001 From: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org> Date: Tue, 20 Aug 2024 11:40:22 +0200 Subject: [PATCH] cpuidle: riscv-sbi: Use scoped device node handling to fix missing of_node_put Two return statements in sbi_cpuidle_dt_init_states() did not drop the OF node reference count. Solve the issue and simplify entire error handling with scoped/cleanup.h. Fixes: 6abf32f1d9c5 ("cpuidle: Add RISC-V SBI CPU idle driver") Cc: All applicable <stable(a)vger.kernel.org> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org> Reviewed-by: Anup Patel <anup(a)brainfault.org> Link: https://patch.msgid.link/20240820094023.61155-1-krzysztof.kozlowski@linaro.… Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c index a6e123dfe394..5bb3401220d2 100644 --- a/drivers/cpuidle/cpuidle-riscv-sbi.c +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt +#include <linux/cleanup.h> #include <linux/cpuhotplug.h> #include <linux/cpuidle.h> #include <linux/cpumask.h> @@ -236,19 +237,16 @@ static int sbi_cpuidle_dt_init_states(struct device *dev, { struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu); struct device_node *state_node; - struct device_node *cpu_node; u32 *states; int i, ret; - cpu_node = of_cpu_device_node_get(cpu); + struct device_node *cpu_node __free(device_node) = of_cpu_device_node_get(cpu); if (!cpu_node) return -ENODEV; states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL); - if (!states) { - ret = -ENOMEM; - goto fail; - } + if (!states) + return -ENOMEM; /* Parse SBI specific details from state DT nodes */ for (i = 1; i < state_count; i++) { @@ -264,10 +262,8 @@ static int sbi_cpuidle_dt_init_states(struct device *dev, pr_debug("sbi-state %#x index %d\n", states[i], i); } - if (i != state_count) { - ret = -ENODEV; - goto fail; - } + if (i != state_count) + return -ENODEV; /* Initialize optional data, used for the hierarchical topology. */ ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu); @@ -277,10 +273,7 @@ static int sbi_cpuidle_dt_init_states(struct device *dev, /* Store states in the per-cpu struct. */ data->states = states; -fail: - of_node_put(cpu_node); - - return ret; + return 0; } static void sbi_cpuidle_deinit_cpu(int cpu)

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FAILED: patch "[PATCH] icmp: change the order of rate limits" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 8c2bd38b95f75f3d2a08c93e35303e26d480d24e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100131-unfixed-excursion-b8a2@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 8c2bd38b95f7 ("icmp: change the order of rate limits") d0941130c935 ("icmp: Add counters for rate limits") 8032bf1233a7 ("treewide: use get_random_u32_below() instead of deprecated function") c5f0a1728874 ("rhashtable: make test actually random") 197173db990c ("treewide: use get_random_bytes() when possible") a251c17aa558 ("treewide: use get_random_u32() when possible") 7e3cf0843fe5 ("treewide: use get_random_{u8,u16}() when possible, part 1") 8b3ccbc1f1f9 ("treewide: use prandom_u32_max() when possible, part 2") 81895a65ec63 ("treewide: use prandom_u32_max() when possible, part 1") 27bc50fc9064 ("Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8c2bd38b95f75f3d2a08c93e35303e26d480d24e Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet(a)google.com> Date: Thu, 29 Aug 2024 14:46:39 +0000 Subject: [PATCH] icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation. Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited") Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Reported-by: Keyu Man <keyu.man(a)email.ucr.edu> Signed-off-by: Eric Dumazet <edumazet(a)google.com> Reviewed-by: David Ahern <dsahern(a)kernel.org> Cc: Jesper Dangaard Brouer <hawk(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/include/net/ip.h b/include/net/ip.h index c5606cadb1a5..82248813619e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -795,6 +795,8 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb) } bool icmp_global_allow(void); +void icmp_global_consume(void); + extern int sysctl_icmp_msgs_per_sec; extern int sysctl_icmp_msgs_burst; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index b8f56d03fcbb..0078e8fb2e86 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -224,57 +224,59 @@ int sysctl_icmp_msgs_per_sec __read_mostly = 1000; int sysctl_icmp_msgs_burst __read_mostly = 50; static struct { - spinlock_t lock; - u32 credit; + atomic_t credit; u32 stamp; -} icmp_global = { - .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), -}; +} icmp_global; /** * icmp_global_allow - Are we allowed to send one more ICMP message ? * * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec. * Returns false if we reached the limit and can not send another packet. - * Note: called with BH disabled + * Works in tandem with icmp_global_consume(). */ bool icmp_global_allow(void) { - u32 credit, delta, incr = 0, now = (u32)jiffies; - bool rc = false; + u32 delta, now, oldstamp; + int incr, new, old; - /* Check if token bucket is empty and cannot be refilled - * without taking the spinlock. The READ_ONCE() are paired - * with the following WRITE_ONCE() in this same function. + /* Note: many cpus could find this condition true. + * Then later icmp_global_consume() could consume more credits, + * this is an acceptable race. */ - if (!READ_ONCE(icmp_global.credit)) { - delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ); - if (delta < HZ / 50) - return false; - } + if (atomic_read(&icmp_global.credit) > 0) + return true; - spin_lock(&icmp_global.lock); - delta = min_t(u32, now - icmp_global.stamp, HZ); - if (delta >= HZ / 50) { - incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; - if (incr) - WRITE_ONCE(icmp_global.stamp, now); + now = jiffies; + oldstamp = READ_ONCE(icmp_global.stamp); + delta = min_t(u32, now - oldstamp, HZ); + if (delta < HZ / 50) + return false; + + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; + if (!incr) + return false; + + if (cmpxchg(&icmp_global.stamp, oldstamp, now) == oldstamp) { + old = atomic_read(&icmp_global.credit); + do { + new = min(old + incr, READ_ONCE(sysctl_icmp_msgs_burst)); + } while (!atomic_try_cmpxchg(&icmp_global.credit, &old, new)); } - credit = min_t(u32, icmp_global.credit + incr, - READ_ONCE(sysctl_icmp_msgs_burst)); - if (credit) { - /* We want to use a credit of one in average, but need to randomize - * it for security reasons. - */ - credit = max_t(int, credit - get_random_u32_below(3), 0); - rc = true; - } - WRITE_ONCE(icmp_global.credit, credit); - spin_unlock(&icmp_global.lock); - return rc; + return true; } EXPORT_SYMBOL(icmp_global_allow); +void icmp_global_consume(void) +{ + int credits = get_random_u32_below(3); + + /* Note: this might make icmp_global.credit negative. */ + if (credits) + atomic_sub(credits, &icmp_global.credit); +} +EXPORT_SYMBOL(icmp_global_consume); + static bool icmpv4_mask_allow(struct net *net, int type, int code) { if (type > NR_ICMP_TYPES) @@ -291,14 +293,16 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code) return false; } -static bool icmpv4_global_allow(struct net *net, int type, int code) +static bool icmpv4_global_allow(struct net *net, int type, int code, + bool *apply_ratelimit) { if (icmpv4_mask_allow(net, type, code)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -308,15 +312,16 @@ static bool icmpv4_global_allow(struct net *net, int type, int code) */ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, - struct flowi4 *fl4, int type, int code) + struct flowi4 *fl4, int type, int code, + bool apply_ratelimit) { struct dst_entry *dst = &rt->dst; struct inet_peer *peer; bool rc = true; int vif; - if (icmpv4_mask_allow(net, type, code)) - goto out; + if (!apply_ratelimit) + return true; /* No rate limit on loopback */ if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) @@ -331,6 +336,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); + else + icmp_global_consume(); return rc; } @@ -402,6 +409,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); struct net *net = dev_net(rt->dst.dev); + bool apply_ratelimit = false; struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; @@ -413,11 +421,11 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb)) return; - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); - /* global icmp_msgs_per_sec */ - if (!icmpv4_global_allow(net, type, code)) + /* is global icmp_msgs_per_sec exhausted ? */ + if (!icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -450,7 +458,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) goto out_unlock; - if (icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt); ip_rt_put(rt); out_unlock: @@ -596,6 +604,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, int room; struct icmp_bxm icmp_param; struct rtable *rt = skb_rtable(skb_in); + bool apply_ratelimit = false; struct ipcm_cookie ipc; struct flowi4 fl4; __be32 saddr; @@ -677,7 +686,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, } } - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless @@ -685,7 +694,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow) */ if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) && - !icmpv4_global_allow(net, type, code)) + !icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -744,7 +753,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, goto out_unlock; /* peer icmp_ratelimit */ - if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) goto ende; /* RFC says return as much as we can without exceeding 576 bytes. */ diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 7b31674644ef..46f70e4a8351 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -175,14 +175,16 @@ static bool icmpv6_mask_allow(struct net *net, int type) return false; } -static bool icmpv6_global_allow(struct net *net, int type) +static bool icmpv6_global_allow(struct net *net, int type, + bool *apply_ratelimit) { if (icmpv6_mask_allow(net, type)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -191,13 +193,13 @@ static bool icmpv6_global_allow(struct net *net, int type) * Check the ICMP output rate limit */ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, - struct flowi6 *fl6) + struct flowi6 *fl6, bool apply_ratelimit) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; - if (icmpv6_mask_allow(net, type)) + if (!apply_ratelimit) return true; /* @@ -228,6 +230,8 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, if (!res) __ICMP6_INC_STATS(net, ip6_dst_idev(dst), ICMP6_MIB_RATELIMITHOST); + else + icmp_global_consume(); dst_release(dst); return res; } @@ -452,6 +456,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, struct net *net; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; + bool apply_ratelimit = false; struct dst_entry *dst; struct icmp6hdr tmp_hdr; struct flowi6 fl6; @@ -533,11 +538,12 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, return; } - /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ + /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit */ - if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) + if (!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, type, &apply_ratelimit)) goto out_bh_enable; mip6_addr_swap(skb, parm); @@ -575,7 +581,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, np = inet6_sk(sk); - if (!icmpv6_xrlim_allow(sk, type, &fl6)) + if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit)) goto out; tmp_hdr.icmp6_type = type; @@ -717,6 +723,7 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; struct icmp6hdr *icmph = icmp6_hdr(skb); + bool apply_ratelimit = false; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; @@ -781,8 +788,9 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) goto out; /* Check the ratelimit */ - if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) || - !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) + if ((!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) || + !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit)) goto out_dst_release; idev = __in6_dev_get(skb->dev);

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FAILED: patch "[PATCH] icmp: change the order of rate limits" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 8c2bd38b95f75f3d2a08c93e35303e26d480d24e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100130-replay-varied-aaaf@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 8c2bd38b95f7 ("icmp: change the order of rate limits") d0941130c935 ("icmp: Add counters for rate limits") 8032bf1233a7 ("treewide: use get_random_u32_below() instead of deprecated function") c5f0a1728874 ("rhashtable: make test actually random") 197173db990c ("treewide: use get_random_bytes() when possible") a251c17aa558 ("treewide: use get_random_u32() when possible") 7e3cf0843fe5 ("treewide: use get_random_{u8,u16}() when possible, part 1") 8b3ccbc1f1f9 ("treewide: use prandom_u32_max() when possible, part 2") 81895a65ec63 ("treewide: use prandom_u32_max() when possible, part 1") 27bc50fc9064 ("Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8c2bd38b95f75f3d2a08c93e35303e26d480d24e Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet(a)google.com> Date: Thu, 29 Aug 2024 14:46:39 +0000 Subject: [PATCH] icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation. Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited") Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Reported-by: Keyu Man <keyu.man(a)email.ucr.edu> Signed-off-by: Eric Dumazet <edumazet(a)google.com> Reviewed-by: David Ahern <dsahern(a)kernel.org> Cc: Jesper Dangaard Brouer <hawk(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/include/net/ip.h b/include/net/ip.h index c5606cadb1a5..82248813619e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -795,6 +795,8 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb) } bool icmp_global_allow(void); +void icmp_global_consume(void); + extern int sysctl_icmp_msgs_per_sec; extern int sysctl_icmp_msgs_burst; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index b8f56d03fcbb..0078e8fb2e86 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -224,57 +224,59 @@ int sysctl_icmp_msgs_per_sec __read_mostly = 1000; int sysctl_icmp_msgs_burst __read_mostly = 50; static struct { - spinlock_t lock; - u32 credit; + atomic_t credit; u32 stamp; -} icmp_global = { - .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), -}; +} icmp_global; /** * icmp_global_allow - Are we allowed to send one more ICMP message ? * * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec. * Returns false if we reached the limit and can not send another packet. - * Note: called with BH disabled + * Works in tandem with icmp_global_consume(). */ bool icmp_global_allow(void) { - u32 credit, delta, incr = 0, now = (u32)jiffies; - bool rc = false; + u32 delta, now, oldstamp; + int incr, new, old; - /* Check if token bucket is empty and cannot be refilled - * without taking the spinlock. The READ_ONCE() are paired - * with the following WRITE_ONCE() in this same function. + /* Note: many cpus could find this condition true. + * Then later icmp_global_consume() could consume more credits, + * this is an acceptable race. */ - if (!READ_ONCE(icmp_global.credit)) { - delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ); - if (delta < HZ / 50) - return false; - } + if (atomic_read(&icmp_global.credit) > 0) + return true; - spin_lock(&icmp_global.lock); - delta = min_t(u32, now - icmp_global.stamp, HZ); - if (delta >= HZ / 50) { - incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; - if (incr) - WRITE_ONCE(icmp_global.stamp, now); + now = jiffies; + oldstamp = READ_ONCE(icmp_global.stamp); + delta = min_t(u32, now - oldstamp, HZ); + if (delta < HZ / 50) + return false; + + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; + if (!incr) + return false; + + if (cmpxchg(&icmp_global.stamp, oldstamp, now) == oldstamp) { + old = atomic_read(&icmp_global.credit); + do { + new = min(old + incr, READ_ONCE(sysctl_icmp_msgs_burst)); + } while (!atomic_try_cmpxchg(&icmp_global.credit, &old, new)); } - credit = min_t(u32, icmp_global.credit + incr, - READ_ONCE(sysctl_icmp_msgs_burst)); - if (credit) { - /* We want to use a credit of one in average, but need to randomize - * it for security reasons. - */ - credit = max_t(int, credit - get_random_u32_below(3), 0); - rc = true; - } - WRITE_ONCE(icmp_global.credit, credit); - spin_unlock(&icmp_global.lock); - return rc; + return true; } EXPORT_SYMBOL(icmp_global_allow); +void icmp_global_consume(void) +{ + int credits = get_random_u32_below(3); + + /* Note: this might make icmp_global.credit negative. */ + if (credits) + atomic_sub(credits, &icmp_global.credit); +} +EXPORT_SYMBOL(icmp_global_consume); + static bool icmpv4_mask_allow(struct net *net, int type, int code) { if (type > NR_ICMP_TYPES) @@ -291,14 +293,16 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code) return false; } -static bool icmpv4_global_allow(struct net *net, int type, int code) +static bool icmpv4_global_allow(struct net *net, int type, int code, + bool *apply_ratelimit) { if (icmpv4_mask_allow(net, type, code)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -308,15 +312,16 @@ static bool icmpv4_global_allow(struct net *net, int type, int code) */ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, - struct flowi4 *fl4, int type, int code) + struct flowi4 *fl4, int type, int code, + bool apply_ratelimit) { struct dst_entry *dst = &rt->dst; struct inet_peer *peer; bool rc = true; int vif; - if (icmpv4_mask_allow(net, type, code)) - goto out; + if (!apply_ratelimit) + return true; /* No rate limit on loopback */ if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) @@ -331,6 +336,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); + else + icmp_global_consume(); return rc; } @@ -402,6 +409,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); struct net *net = dev_net(rt->dst.dev); + bool apply_ratelimit = false; struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; @@ -413,11 +421,11 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb)) return; - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); - /* global icmp_msgs_per_sec */ - if (!icmpv4_global_allow(net, type, code)) + /* is global icmp_msgs_per_sec exhausted ? */ + if (!icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -450,7 +458,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) goto out_unlock; - if (icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt); ip_rt_put(rt); out_unlock: @@ -596,6 +604,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, int room; struct icmp_bxm icmp_param; struct rtable *rt = skb_rtable(skb_in); + bool apply_ratelimit = false; struct ipcm_cookie ipc; struct flowi4 fl4; __be32 saddr; @@ -677,7 +686,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, } } - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless @@ -685,7 +694,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow) */ if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) && - !icmpv4_global_allow(net, type, code)) + !icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -744,7 +753,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, goto out_unlock; /* peer icmp_ratelimit */ - if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) goto ende; /* RFC says return as much as we can without exceeding 576 bytes. */ diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 7b31674644ef..46f70e4a8351 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -175,14 +175,16 @@ static bool icmpv6_mask_allow(struct net *net, int type) return false; } -static bool icmpv6_global_allow(struct net *net, int type) +static bool icmpv6_global_allow(struct net *net, int type, + bool *apply_ratelimit) { if (icmpv6_mask_allow(net, type)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -191,13 +193,13 @@ static bool icmpv6_global_allow(struct net *net, int type) * Check the ICMP output rate limit */ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, - struct flowi6 *fl6) + struct flowi6 *fl6, bool apply_ratelimit) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; - if (icmpv6_mask_allow(net, type)) + if (!apply_ratelimit) return true; /* @@ -228,6 +230,8 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, if (!res) __ICMP6_INC_STATS(net, ip6_dst_idev(dst), ICMP6_MIB_RATELIMITHOST); + else + icmp_global_consume(); dst_release(dst); return res; } @@ -452,6 +456,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, struct net *net; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; + bool apply_ratelimit = false; struct dst_entry *dst; struct icmp6hdr tmp_hdr; struct flowi6 fl6; @@ -533,11 +538,12 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, return; } - /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ + /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit */ - if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) + if (!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, type, &apply_ratelimit)) goto out_bh_enable; mip6_addr_swap(skb, parm); @@ -575,7 +581,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, np = inet6_sk(sk); - if (!icmpv6_xrlim_allow(sk, type, &fl6)) + if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit)) goto out; tmp_hdr.icmp6_type = type; @@ -717,6 +723,7 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; struct icmp6hdr *icmph = icmp6_hdr(skb); + bool apply_ratelimit = false; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; @@ -781,8 +788,9 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) goto out; /* Check the ratelimit */ - if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) || - !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) + if ((!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) || + !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit)) goto out_dst_release; idev = __in6_dev_get(skb->dev);

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FAILED: patch "[PATCH] icmp: change the order of rate limits" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 8c2bd38b95f75f3d2a08c93e35303e26d480d24e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100129-cottage-pushiness-6e12@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: 8c2bd38b95f7 ("icmp: change the order of rate limits") d0941130c935 ("icmp: Add counters for rate limits") 8032bf1233a7 ("treewide: use get_random_u32_below() instead of deprecated function") c5f0a1728874 ("rhashtable: make test actually random") 197173db990c ("treewide: use get_random_bytes() when possible") a251c17aa558 ("treewide: use get_random_u32() when possible") 7e3cf0843fe5 ("treewide: use get_random_{u8,u16}() when possible, part 1") 8b3ccbc1f1f9 ("treewide: use prandom_u32_max() when possible, part 2") 81895a65ec63 ("treewide: use prandom_u32_max() when possible, part 1") 27bc50fc9064 ("Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8c2bd38b95f75f3d2a08c93e35303e26d480d24e Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet(a)google.com> Date: Thu, 29 Aug 2024 14:46:39 +0000 Subject: [PATCH] icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation. Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited") Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Reported-by: Keyu Man <keyu.man(a)email.ucr.edu> Signed-off-by: Eric Dumazet <edumazet(a)google.com> Reviewed-by: David Ahern <dsahern(a)kernel.org> Cc: Jesper Dangaard Brouer <hawk(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/include/net/ip.h b/include/net/ip.h index c5606cadb1a5..82248813619e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -795,6 +795,8 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb) } bool icmp_global_allow(void); +void icmp_global_consume(void); + extern int sysctl_icmp_msgs_per_sec; extern int sysctl_icmp_msgs_burst; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index b8f56d03fcbb..0078e8fb2e86 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -224,57 +224,59 @@ int sysctl_icmp_msgs_per_sec __read_mostly = 1000; int sysctl_icmp_msgs_burst __read_mostly = 50; static struct { - spinlock_t lock; - u32 credit; + atomic_t credit; u32 stamp; -} icmp_global = { - .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), -}; +} icmp_global; /** * icmp_global_allow - Are we allowed to send one more ICMP message ? * * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec. * Returns false if we reached the limit and can not send another packet. - * Note: called with BH disabled + * Works in tandem with icmp_global_consume(). */ bool icmp_global_allow(void) { - u32 credit, delta, incr = 0, now = (u32)jiffies; - bool rc = false; + u32 delta, now, oldstamp; + int incr, new, old; - /* Check if token bucket is empty and cannot be refilled - * without taking the spinlock. The READ_ONCE() are paired - * with the following WRITE_ONCE() in this same function. + /* Note: many cpus could find this condition true. + * Then later icmp_global_consume() could consume more credits, + * this is an acceptable race. */ - if (!READ_ONCE(icmp_global.credit)) { - delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ); - if (delta < HZ / 50) - return false; - } + if (atomic_read(&icmp_global.credit) > 0) + return true; - spin_lock(&icmp_global.lock); - delta = min_t(u32, now - icmp_global.stamp, HZ); - if (delta >= HZ / 50) { - incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; - if (incr) - WRITE_ONCE(icmp_global.stamp, now); + now = jiffies; + oldstamp = READ_ONCE(icmp_global.stamp); + delta = min_t(u32, now - oldstamp, HZ); + if (delta < HZ / 50) + return false; + + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; + if (!incr) + return false; + + if (cmpxchg(&icmp_global.stamp, oldstamp, now) == oldstamp) { + old = atomic_read(&icmp_global.credit); + do { + new = min(old + incr, READ_ONCE(sysctl_icmp_msgs_burst)); + } while (!atomic_try_cmpxchg(&icmp_global.credit, &old, new)); } - credit = min_t(u32, icmp_global.credit + incr, - READ_ONCE(sysctl_icmp_msgs_burst)); - if (credit) { - /* We want to use a credit of one in average, but need to randomize - * it for security reasons. - */ - credit = max_t(int, credit - get_random_u32_below(3), 0); - rc = true; - } - WRITE_ONCE(icmp_global.credit, credit); - spin_unlock(&icmp_global.lock); - return rc; + return true; } EXPORT_SYMBOL(icmp_global_allow); +void icmp_global_consume(void) +{ + int credits = get_random_u32_below(3); + + /* Note: this might make icmp_global.credit negative. */ + if (credits) + atomic_sub(credits, &icmp_global.credit); +} +EXPORT_SYMBOL(icmp_global_consume); + static bool icmpv4_mask_allow(struct net *net, int type, int code) { if (type > NR_ICMP_TYPES) @@ -291,14 +293,16 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code) return false; } -static bool icmpv4_global_allow(struct net *net, int type, int code) +static bool icmpv4_global_allow(struct net *net, int type, int code, + bool *apply_ratelimit) { if (icmpv4_mask_allow(net, type, code)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -308,15 +312,16 @@ static bool icmpv4_global_allow(struct net *net, int type, int code) */ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, - struct flowi4 *fl4, int type, int code) + struct flowi4 *fl4, int type, int code, + bool apply_ratelimit) { struct dst_entry *dst = &rt->dst; struct inet_peer *peer; bool rc = true; int vif; - if (icmpv4_mask_allow(net, type, code)) - goto out; + if (!apply_ratelimit) + return true; /* No rate limit on loopback */ if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) @@ -331,6 +336,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); + else + icmp_global_consume(); return rc; } @@ -402,6 +409,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); struct net *net = dev_net(rt->dst.dev); + bool apply_ratelimit = false; struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; @@ -413,11 +421,11 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb)) return; - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); - /* global icmp_msgs_per_sec */ - if (!icmpv4_global_allow(net, type, code)) + /* is global icmp_msgs_per_sec exhausted ? */ + if (!icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -450,7 +458,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) goto out_unlock; - if (icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt); ip_rt_put(rt); out_unlock: @@ -596,6 +604,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, int room; struct icmp_bxm icmp_param; struct rtable *rt = skb_rtable(skb_in); + bool apply_ratelimit = false; struct ipcm_cookie ipc; struct flowi4 fl4; __be32 saddr; @@ -677,7 +686,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, } } - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless @@ -685,7 +694,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow) */ if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) && - !icmpv4_global_allow(net, type, code)) + !icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -744,7 +753,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, goto out_unlock; /* peer icmp_ratelimit */ - if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) goto ende; /* RFC says return as much as we can without exceeding 576 bytes. */ diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 7b31674644ef..46f70e4a8351 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -175,14 +175,16 @@ static bool icmpv6_mask_allow(struct net *net, int type) return false; } -static bool icmpv6_global_allow(struct net *net, int type) +static bool icmpv6_global_allow(struct net *net, int type, + bool *apply_ratelimit) { if (icmpv6_mask_allow(net, type)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -191,13 +193,13 @@ static bool icmpv6_global_allow(struct net *net, int type) * Check the ICMP output rate limit */ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, - struct flowi6 *fl6) + struct flowi6 *fl6, bool apply_ratelimit) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; - if (icmpv6_mask_allow(net, type)) + if (!apply_ratelimit) return true; /* @@ -228,6 +230,8 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, if (!res) __ICMP6_INC_STATS(net, ip6_dst_idev(dst), ICMP6_MIB_RATELIMITHOST); + else + icmp_global_consume(); dst_release(dst); return res; } @@ -452,6 +456,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, struct net *net; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; + bool apply_ratelimit = false; struct dst_entry *dst; struct icmp6hdr tmp_hdr; struct flowi6 fl6; @@ -533,11 +538,12 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, return; } - /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ + /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit */ - if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) + if (!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, type, &apply_ratelimit)) goto out_bh_enable; mip6_addr_swap(skb, parm); @@ -575,7 +581,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, np = inet6_sk(sk); - if (!icmpv6_xrlim_allow(sk, type, &fl6)) + if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit)) goto out; tmp_hdr.icmp6_type = type; @@ -717,6 +723,7 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; struct icmp6hdr *icmph = icmp6_hdr(skb); + bool apply_ratelimit = false; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; @@ -781,8 +788,9 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) goto out; /* Check the ratelimit */ - if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) || - !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) + if ((!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) || + !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit)) goto out_dst_release; idev = __in6_dev_get(skb->dev);

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FAILED: patch "[PATCH] icmp: change the order of rate limits" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 8c2bd38b95f75f3d2a08c93e35303e26d480d24e # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024100128-unsealed-flakily-f407@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: 8c2bd38b95f7 ("icmp: change the order of rate limits") d0941130c935 ("icmp: Add counters for rate limits") 8032bf1233a7 ("treewide: use get_random_u32_below() instead of deprecated function") c5f0a1728874 ("rhashtable: make test actually random") 197173db990c ("treewide: use get_random_bytes() when possible") a251c17aa558 ("treewide: use get_random_u32() when possible") 7e3cf0843fe5 ("treewide: use get_random_{u8,u16}() when possible, part 1") 8b3ccbc1f1f9 ("treewide: use prandom_u32_max() when possible, part 2") 81895a65ec63 ("treewide: use prandom_u32_max() when possible, part 1") 27bc50fc9064 ("Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8c2bd38b95f75f3d2a08c93e35303e26d480d24e Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet(a)google.com> Date: Thu, 29 Aug 2024 14:46:39 +0000 Subject: [PATCH] icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation. Fixes: c0303efeab73 ("net: reduce cycles spend on ICMP replies that gets rate limited") Fixes: 4cdf507d5452 ("icmp: add a global rate limitation") Reported-by: Keyu Man <keyu.man(a)email.ucr.edu> Signed-off-by: Eric Dumazet <edumazet(a)google.com> Reviewed-by: David Ahern <dsahern(a)kernel.org> Cc: Jesper Dangaard Brouer <hawk(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/20240829144641.3880376-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> diff --git a/include/net/ip.h b/include/net/ip.h index c5606cadb1a5..82248813619e 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -795,6 +795,8 @@ static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb) } bool icmp_global_allow(void); +void icmp_global_consume(void); + extern int sysctl_icmp_msgs_per_sec; extern int sysctl_icmp_msgs_burst; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index b8f56d03fcbb..0078e8fb2e86 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -224,57 +224,59 @@ int sysctl_icmp_msgs_per_sec __read_mostly = 1000; int sysctl_icmp_msgs_burst __read_mostly = 50; static struct { - spinlock_t lock; - u32 credit; + atomic_t credit; u32 stamp; -} icmp_global = { - .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock), -}; +} icmp_global; /** * icmp_global_allow - Are we allowed to send one more ICMP message ? * * Uses a token bucket to limit our ICMP messages to ~sysctl_icmp_msgs_per_sec. * Returns false if we reached the limit and can not send another packet. - * Note: called with BH disabled + * Works in tandem with icmp_global_consume(). */ bool icmp_global_allow(void) { - u32 credit, delta, incr = 0, now = (u32)jiffies; - bool rc = false; + u32 delta, now, oldstamp; + int incr, new, old; - /* Check if token bucket is empty and cannot be refilled - * without taking the spinlock. The READ_ONCE() are paired - * with the following WRITE_ONCE() in this same function. + /* Note: many cpus could find this condition true. + * Then later icmp_global_consume() could consume more credits, + * this is an acceptable race. */ - if (!READ_ONCE(icmp_global.credit)) { - delta = min_t(u32, now - READ_ONCE(icmp_global.stamp), HZ); - if (delta < HZ / 50) - return false; - } + if (atomic_read(&icmp_global.credit) > 0) + return true; - spin_lock(&icmp_global.lock); - delta = min_t(u32, now - icmp_global.stamp, HZ); - if (delta >= HZ / 50) { - incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; - if (incr) - WRITE_ONCE(icmp_global.stamp, now); + now = jiffies; + oldstamp = READ_ONCE(icmp_global.stamp); + delta = min_t(u32, now - oldstamp, HZ); + if (delta < HZ / 50) + return false; + + incr = READ_ONCE(sysctl_icmp_msgs_per_sec) * delta / HZ; + if (!incr) + return false; + + if (cmpxchg(&icmp_global.stamp, oldstamp, now) == oldstamp) { + old = atomic_read(&icmp_global.credit); + do { + new = min(old + incr, READ_ONCE(sysctl_icmp_msgs_burst)); + } while (!atomic_try_cmpxchg(&icmp_global.credit, &old, new)); } - credit = min_t(u32, icmp_global.credit + incr, - READ_ONCE(sysctl_icmp_msgs_burst)); - if (credit) { - /* We want to use a credit of one in average, but need to randomize - * it for security reasons. - */ - credit = max_t(int, credit - get_random_u32_below(3), 0); - rc = true; - } - WRITE_ONCE(icmp_global.credit, credit); - spin_unlock(&icmp_global.lock); - return rc; + return true; } EXPORT_SYMBOL(icmp_global_allow); +void icmp_global_consume(void) +{ + int credits = get_random_u32_below(3); + + /* Note: this might make icmp_global.credit negative. */ + if (credits) + atomic_sub(credits, &icmp_global.credit); +} +EXPORT_SYMBOL(icmp_global_consume); + static bool icmpv4_mask_allow(struct net *net, int type, int code) { if (type > NR_ICMP_TYPES) @@ -291,14 +293,16 @@ static bool icmpv4_mask_allow(struct net *net, int type, int code) return false; } -static bool icmpv4_global_allow(struct net *net, int type, int code) +static bool icmpv4_global_allow(struct net *net, int type, int code, + bool *apply_ratelimit) { if (icmpv4_mask_allow(net, type, code)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -308,15 +312,16 @@ static bool icmpv4_global_allow(struct net *net, int type, int code) */ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, - struct flowi4 *fl4, int type, int code) + struct flowi4 *fl4, int type, int code, + bool apply_ratelimit) { struct dst_entry *dst = &rt->dst; struct inet_peer *peer; bool rc = true; int vif; - if (icmpv4_mask_allow(net, type, code)) - goto out; + if (!apply_ratelimit) + return true; /* No rate limit on loopback */ if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) @@ -331,6 +336,8 @@ static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt, out: if (!rc) __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITHOST); + else + icmp_global_consume(); return rc; } @@ -402,6 +409,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) struct ipcm_cookie ipc; struct rtable *rt = skb_rtable(skb); struct net *net = dev_net(rt->dst.dev); + bool apply_ratelimit = false; struct flowi4 fl4; struct sock *sk; struct inet_sock *inet; @@ -413,11 +421,11 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) if (ip_options_echo(net, &icmp_param->replyopts.opt.opt, skb)) return; - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); - /* global icmp_msgs_per_sec */ - if (!icmpv4_global_allow(net, type, code)) + /* is global icmp_msgs_per_sec exhausted ? */ + if (!icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -450,7 +458,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) goto out_unlock; - if (icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt); ip_rt_put(rt); out_unlock: @@ -596,6 +604,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, int room; struct icmp_bxm icmp_param; struct rtable *rt = skb_rtable(skb_in); + bool apply_ratelimit = false; struct ipcm_cookie ipc; struct flowi4 fl4; __be32 saddr; @@ -677,7 +686,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, } } - /* Needed by both icmp_global_allow and icmp_xmit_lock */ + /* Needed by both icmpv4_global_allow and icmp_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit, unless @@ -685,7 +694,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, * loopback, then peer ratelimit still work (in icmpv4_xrlim_allow) */ if (!(skb_in->dev && (skb_in->dev->flags&IFF_LOOPBACK)) && - !icmpv4_global_allow(net, type, code)) + !icmpv4_global_allow(net, type, code, &apply_ratelimit)) goto out_bh_enable; sk = icmp_xmit_lock(net); @@ -744,7 +753,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, goto out_unlock; /* peer icmp_ratelimit */ - if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code)) + if (!icmpv4_xrlim_allow(net, rt, &fl4, type, code, apply_ratelimit)) goto ende; /* RFC says return as much as we can without exceeding 576 bytes. */ diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index 7b31674644ef..46f70e4a8351 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -175,14 +175,16 @@ static bool icmpv6_mask_allow(struct net *net, int type) return false; } -static bool icmpv6_global_allow(struct net *net, int type) +static bool icmpv6_global_allow(struct net *net, int type, + bool *apply_ratelimit) { if (icmpv6_mask_allow(net, type)) return true; - if (icmp_global_allow()) + if (icmp_global_allow()) { + *apply_ratelimit = true; return true; - + } __ICMP_INC_STATS(net, ICMP_MIB_RATELIMITGLOBAL); return false; } @@ -191,13 +193,13 @@ static bool icmpv6_global_allow(struct net *net, int type) * Check the ICMP output rate limit */ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, - struct flowi6 *fl6) + struct flowi6 *fl6, bool apply_ratelimit) { struct net *net = sock_net(sk); struct dst_entry *dst; bool res = false; - if (icmpv6_mask_allow(net, type)) + if (!apply_ratelimit) return true; /* @@ -228,6 +230,8 @@ static bool icmpv6_xrlim_allow(struct sock *sk, u8 type, if (!res) __ICMP6_INC_STATS(net, ip6_dst_idev(dst), ICMP6_MIB_RATELIMITHOST); + else + icmp_global_consume(); dst_release(dst); return res; } @@ -452,6 +456,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, struct net *net; struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; + bool apply_ratelimit = false; struct dst_entry *dst; struct icmp6hdr tmp_hdr; struct flowi6 fl6; @@ -533,11 +538,12 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, return; } - /* Needed by both icmp_global_allow and icmpv6_xmit_lock */ + /* Needed by both icmpv6_global_allow and icmpv6_xmit_lock */ local_bh_disable(); /* Check global sysctl_icmp_msgs_per_sec ratelimit */ - if (!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, type)) + if (!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, type, &apply_ratelimit)) goto out_bh_enable; mip6_addr_swap(skb, parm); @@ -575,7 +581,7 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, np = inet6_sk(sk); - if (!icmpv6_xrlim_allow(sk, type, &fl6)) + if (!icmpv6_xrlim_allow(sk, type, &fl6, apply_ratelimit)) goto out; tmp_hdr.icmp6_type = type; @@ -717,6 +723,7 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) struct ipv6_pinfo *np; const struct in6_addr *saddr = NULL; struct icmp6hdr *icmph = icmp6_hdr(skb); + bool apply_ratelimit = false; struct icmp6hdr tmp_hdr; struct flowi6 fl6; struct icmpv6_msg msg; @@ -781,8 +788,9 @@ static enum skb_drop_reason icmpv6_echo_reply(struct sk_buff *skb) goto out; /* Check the ratelimit */ - if ((!(skb->dev->flags & IFF_LOOPBACK) && !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY)) || - !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6)) + if ((!(skb->dev->flags & IFF_LOOPBACK) && + !icmpv6_global_allow(net, ICMPV6_ECHO_REPLY, &apply_ratelimit)) || + !icmpv6_xrlim_allow(sk, ICMPV6_ECHO_REPLY, &fl6, apply_ratelimit)) goto out_dst_release; idev = __in6_dev_get(skb->dev);

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Linux-stable-mirror October 2024