6.17-stable review patch. If anyone has any objections, please let me know.

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From: Stephen Smalley stephen.smalley.work@gmail.com

commit dde3a5d0f4dce1d1a6095e6b8eeb59b75d28fb3b upstream.

The avdcache is meant to be per-task; move it to a new task_security_struct that is duplicated per-task.

Cc: stable@vger.kernel.org Fixes: 5d7ddc59b3d89b724a5aa8f30d0db94ff8d2d93f ("selinux: reduce path walk overhead") Signed-off-by: Stephen Smalley stephen.smalley.work@gmail.com [PM: line length fixes] Signed-off-by: Paul Moore paul@paul-moore.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- security/selinux/hooks.c | 31 ++++++++++++++++++------------- security/selinux/include/objsec.h | 14 ++++++++++++-- 2 files changed, 30 insertions(+), 15 deletions(-)

--- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -215,7 +215,7 @@ static void cred_init_security(void) /* NOTE: the lsm framework zeros out the buffer on allocation */

tsec = selinux_cred(unrcu_pointer(current->real_cred)); - tsec->osid = tsec->sid = tsec->avdcache.sid = SECINITSID_KERNEL; + tsec->osid = tsec->sid = SECINITSID_KERNEL; }

/* @@ -3106,10 +3106,10 @@ static noinline int audit_inode_permissi * Clear the task's AVD cache in @tsec and reset it to the current policy's * and task's info. */ -static inline void task_avdcache_reset(struct cred_security_struct *tsec) +static inline void task_avdcache_reset(struct task_security_struct *tsec) { memset(&tsec->avdcache.dir, 0, sizeof(tsec->avdcache.dir)); - tsec->avdcache.sid = tsec->sid; + tsec->avdcache.sid = current_sid(); tsec->avdcache.seqno = avc_policy_seqno(); tsec->avdcache.dir_spot = TSEC_AVDC_DIR_SIZE - 1; } @@ -3123,7 +3123,7 @@ static inline void task_avdcache_reset(s * Search @tsec for a AVD cache entry that matches @isec and return it to the * caller via @avdc. Returns 0 if a match is found, negative values otherwise. */ -static inline int task_avdcache_search(struct cred_security_struct *tsec, +static inline int task_avdcache_search(struct task_security_struct *tsec, struct inode_security_struct *isec, struct avdc_entry **avdc) { @@ -3133,7 +3133,7 @@ static inline int task_avdcache_search(s if (isec->sclass != SECCLASS_DIR) return -ENOENT;

- if (unlikely(tsec->sid != tsec->avdcache.sid || + if (unlikely(current_sid() != tsec->avdcache.sid || tsec->avdcache.seqno != avc_policy_seqno())) { task_avdcache_reset(tsec); return -ENOENT; @@ -3163,7 +3163,7 @@ static inline int task_avdcache_search(s * Update the AVD cache in @tsec with the @avdc and @audited info associated * with @isec. */ -static inline void task_avdcache_update(struct cred_security_struct *tsec, +static inline void task_avdcache_update(struct task_security_struct *tsec, struct inode_security_struct *isec, struct av_decision *avd, u32 audited) @@ -3197,7 +3197,8 @@ static int selinux_inode_permission(stru { int mask; u32 perms; - struct cred_security_struct *tsec; + u32 sid = current_sid(); + struct task_security_struct *tsec; struct inode_security_struct *isec; struct avdc_entry *avdc; int rc, rc2; @@ -3209,8 +3210,8 @@ static int selinux_inode_permission(stru if (!mask) return 0;

- tsec = selinux_cred(current_cred()); - if (task_avdcache_permnoaudit(tsec)) + tsec = selinux_task(current); + if (task_avdcache_permnoaudit(tsec, sid)) return 0;

isec = inode_security_rcu(inode, requested & MAY_NOT_BLOCK); @@ -3230,7 +3231,7 @@ static int selinux_inode_permission(stru struct av_decision avd;

/* Cache miss. */ - rc = avc_has_perm_noaudit(tsec->sid, isec->sid, isec->sclass, + rc = avc_has_perm_noaudit(sid, isec->sid, isec->sclass, perms, 0, &avd); audited = avc_audit_required(perms, &avd, rc, (requested & MAY_ACCESS) ? FILE__AUDIT_ACCESS : 0, @@ -3279,11 +3280,11 @@ static int selinux_inode_setattr(struct

static int selinux_inode_getattr(const struct path *path) { - struct cred_security_struct *tsec; + struct task_security_struct *tsec;

- tsec = selinux_cred(current_cred()); + tsec = selinux_task(current);

- if (task_avdcache_permnoaudit(tsec)) + if (task_avdcache_permnoaudit(tsec, current_sid())) return 0;

return path_has_perm(current_cred(), path, FILE__GETATTR); @@ -4147,7 +4148,10 @@ static int selinux_task_alloc(struct tas unsigned long clone_flags) { u32 sid = current_sid(); + struct task_security_struct *old_tsec = selinux_task(current); + struct task_security_struct *new_tsec = selinux_task(task);

+ *new_tsec = *old_tsec; return avc_has_perm(sid, sid, SECCLASS_PROCESS, PROCESS__FORK, NULL); }

@@ -7170,6 +7174,7 @@ static void selinux_bpf_token_free(struc

struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = { .lbs_cred = sizeof(struct cred_security_struct), + .lbs_task = sizeof(struct task_security_struct), .lbs_file = sizeof(struct file_security_struct), .lbs_inode = sizeof(struct inode_security_struct), .lbs_ipc = sizeof(struct ipc_security_struct), --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -43,6 +43,9 @@ struct cred_security_struct { u32 create_sid; /* fscreate SID */ u32 keycreate_sid; /* keycreate SID */ u32 sockcreate_sid; /* fscreate SID */ +} __randomize_layout; + +struct task_security_struct { #define TSEC_AVDC_DIR_SIZE (1 << 2) struct { u32 sid; /* current SID for cached entries */ @@ -53,10 +56,11 @@ struct cred_security_struct { } avdcache; } __randomize_layout;

-static inline bool task_avdcache_permnoaudit(struct cred_security_struct *tsec) +static inline bool task_avdcache_permnoaudit(struct task_security_struct *tsec, + u32 sid) { return (tsec->avdcache.permissive_neveraudit && - tsec->sid == tsec->avdcache.sid && + sid == tsec->avdcache.sid && tsec->avdcache.seqno == avc_policy_seqno()); }

@@ -176,6 +180,12 @@ static inline struct cred_security_struc return cred->security + selinux_blob_sizes.lbs_cred; }

+static inline struct task_security_struct * +selinux_task(const struct task_struct *task) +{ + return task->security + selinux_blob_sizes.lbs_task; +} + static inline struct file_security_struct *selinux_file(const struct file *file) { return file->f_security + selinux_blob_sizes.lbs_file;