December 2020 - Linux-stable-mirror

FAILED: patch "[PATCH] ext4: prevent creating duplicate encrypted filenames" 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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 75d18cd1868c2aee43553723872c35d7908f240f Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:06 -0800 Subject: [PATCH] ext4: prevent creating duplicate encrypted filenames As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key. Fix this bug on ext4 by rejecting no-key dentries in ext4_add_entry(). Note that the duplicate check in ext4_find_dest_de() sometimes prevented this bug. However in many cases it didn't, since ext4_find_dest_de() doesn't examine every dentry. Fixes: 4461471107b7 ("ext4 crypto: enable filename encryption") Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-3-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 33509266f5a0..793fc7db9d28 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2195,6 +2195,9 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry, if (!dentry->d_name.len) return -EINVAL; + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + #ifdef CONFIG_UNICODE if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) && sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))

3 years, 10 months

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FAILED: patch "[PATCH] ubifs: prevent creating duplicate encrypted filenames" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 76786a0f083473de31678bdb259a3d4167cf756d Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:08 -0800 Subject: [PATCH] ubifs: prevent creating duplicate encrypted filenames As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key. Fix this bug on ubifs by rejecting no-key dentries in ubifs_create(), ubifs_mkdir(), ubifs_mknod(), and ubifs_symlink(). Note that ubifs doesn't actually report the duplicate filenames from readdir, but rather it seems to replace the original dentry with a new one (which is still wrong, just a different effect from ext4). On ubifs, this fixes xfstest generic/595 as well as the new xfstest I wrote specifically for this bug. Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames") Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 155521e51ac5..08fde777c324 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -270,6 +270,15 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry, return d_splice_alias(inode, dentry); } +static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry, + struct fscrypt_name *nm) +{ + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + + return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm); +} + static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { @@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry, return err; } - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) { kfree(dev); goto out_budg; @@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg;

3 years, 10 months

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FAILED: patch "[PATCH] ubifs: prevent creating duplicate encrypted filenames" 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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 76786a0f083473de31678bdb259a3d4167cf756d Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:08 -0800 Subject: [PATCH] ubifs: prevent creating duplicate encrypted filenames As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key. Fix this bug on ubifs by rejecting no-key dentries in ubifs_create(), ubifs_mkdir(), ubifs_mknod(), and ubifs_symlink(). Note that ubifs doesn't actually report the duplicate filenames from readdir, but rather it seems to replace the original dentry with a new one (which is still wrong, just a different effect from ext4). On ubifs, this fixes xfstest generic/595 as well as the new xfstest I wrote specifically for this bug. Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames") Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 155521e51ac5..08fde777c324 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -270,6 +270,15 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry, return d_splice_alias(inode, dentry); } +static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry, + struct fscrypt_name *nm) +{ + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + + return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm); +} + static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { @@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry, return err; } - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) { kfree(dev); goto out_budg; @@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg;

3 years, 10 months

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FAILED: patch "[PATCH] ubifs: prevent creating duplicate encrypted filenames" 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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 76786a0f083473de31678bdb259a3d4167cf756d Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:08 -0800 Subject: [PATCH] ubifs: prevent creating duplicate encrypted filenames As described in "fscrypt: add fscrypt_is_nokey_name()", it's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the directory's encryption key. Fix this bug on ubifs by rejecting no-key dentries in ubifs_create(), ubifs_mkdir(), ubifs_mknod(), and ubifs_symlink(). Note that ubifs doesn't actually report the duplicate filenames from readdir, but rather it seems to replace the original dentry with a new one (which is still wrong, just a different effect from ext4). On ubifs, this fixes xfstest generic/595 as well as the new xfstest I wrote specifically for this bug. Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames") Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 155521e51ac5..08fde777c324 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -270,6 +270,15 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry, return d_splice_alias(inode, dentry); } +static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry, + struct fscrypt_name *nm) +{ + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + + return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm); +} + static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { @@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry, return err; } - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) { kfree(dev); goto out_budg; @@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg;

3 years, 10 months

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FAILED: patch "[PATCH] fscrypt: add fscrypt_is_nokey_name()" failed to apply to 4.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.4-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 159e1de201b6fca10bfec50405a3b53a561096a8 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:05 -0800 Subject: [PATCH] fscrypt: add fscrypt_is_nokey_name() It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..061418be4b08 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,7 +86,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; if (old_dir != new_dir) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..8e1d31c959bf 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) dentry->d_flags &= ~DCACHE_NOKEY_NAME; } +/** + * fscrypt_is_nokey_name() - test whether a dentry is a no-key name + * @dentry: the dentry to check + * + * This returns true if the dentry is a no-key dentry. A no-key dentry is a + * dentry that was created in an encrypted directory that hasn't had its + * encryption key added yet. Such dentries may be either positive or negative. + * + * When a filesystem is asked to create a new filename in an encrypted directory + * and the new filename's dentry is a no-key dentry, it must fail the operation + * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), + * ->rename(), and ->link(). (However, ->rename() and ->link() are already + * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) + * + * This is necessary because creating a filename requires the directory's + * encryption key, but just checking for the key on the directory inode during + * the final filesystem operation doesn't guarantee that the key was available + * during the preceding dentry lookup. And the key must have already been + * available during the dentry lookup in order for it to have been checked + * whether the filename already exists in the directory and for the new file's + * dentry not to be invalidated due to it incorrectly having the no-key flag. + * + * Return: %true if the dentry is a no-key name + */ +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NOKEY_NAME; +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -244,6 +273,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) { } +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return false; +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {

3 years, 10 months

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FAILED: patch "[PATCH] fscrypt: add fscrypt_is_nokey_name()" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 159e1de201b6fca10bfec50405a3b53a561096a8 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:05 -0800 Subject: [PATCH] fscrypt: add fscrypt_is_nokey_name() It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..061418be4b08 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,7 +86,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; if (old_dir != new_dir) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..8e1d31c959bf 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) dentry->d_flags &= ~DCACHE_NOKEY_NAME; } +/** + * fscrypt_is_nokey_name() - test whether a dentry is a no-key name + * @dentry: the dentry to check + * + * This returns true if the dentry is a no-key dentry. A no-key dentry is a + * dentry that was created in an encrypted directory that hasn't had its + * encryption key added yet. Such dentries may be either positive or negative. + * + * When a filesystem is asked to create a new filename in an encrypted directory + * and the new filename's dentry is a no-key dentry, it must fail the operation + * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), + * ->rename(), and ->link(). (However, ->rename() and ->link() are already + * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) + * + * This is necessary because creating a filename requires the directory's + * encryption key, but just checking for the key on the directory inode during + * the final filesystem operation doesn't guarantee that the key was available + * during the preceding dentry lookup. And the key must have already been + * available during the dentry lookup in order for it to have been checked + * whether the filename already exists in the directory and for the new file's + * dentry not to be invalidated due to it incorrectly having the no-key flag. + * + * Return: %true if the dentry is a no-key name + */ +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NOKEY_NAME; +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -244,6 +273,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) { } +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return false; +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {

3 years, 10 months

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FAILED: patch "[PATCH] fscrypt: add fscrypt_is_nokey_name()" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 159e1de201b6fca10bfec50405a3b53a561096a8 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:05 -0800 Subject: [PATCH] fscrypt: add fscrypt_is_nokey_name() It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..061418be4b08 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,7 +86,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; if (old_dir != new_dir) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..8e1d31c959bf 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) dentry->d_flags &= ~DCACHE_NOKEY_NAME; } +/** + * fscrypt_is_nokey_name() - test whether a dentry is a no-key name + * @dentry: the dentry to check + * + * This returns true if the dentry is a no-key dentry. A no-key dentry is a + * dentry that was created in an encrypted directory that hasn't had its + * encryption key added yet. Such dentries may be either positive or negative. + * + * When a filesystem is asked to create a new filename in an encrypted directory + * and the new filename's dentry is a no-key dentry, it must fail the operation + * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), + * ->rename(), and ->link(). (However, ->rename() and ->link() are already + * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) + * + * This is necessary because creating a filename requires the directory's + * encryption key, but just checking for the key on the directory inode during + * the final filesystem operation doesn't guarantee that the key was available + * during the preceding dentry lookup. And the key must have already been + * available during the dentry lookup in order for it to have been checked + * whether the filename already exists in the directory and for the new file's + * dentry not to be invalidated due to it incorrectly having the no-key flag. + * + * Return: %true if the dentry is a no-key name + */ +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NOKEY_NAME; +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -244,6 +273,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) { } +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return false; +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {

3 years, 10 months

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FAILED: patch "[PATCH] fscrypt: add fscrypt_is_nokey_name()" 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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 159e1de201b6fca10bfec50405a3b53a561096a8 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:05 -0800 Subject: [PATCH] fscrypt: add fscrypt_is_nokey_name() It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..061418be4b08 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,7 +86,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; if (old_dir != new_dir) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..8e1d31c959bf 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) dentry->d_flags &= ~DCACHE_NOKEY_NAME; } +/** + * fscrypt_is_nokey_name() - test whether a dentry is a no-key name + * @dentry: the dentry to check + * + * This returns true if the dentry is a no-key dentry. A no-key dentry is a + * dentry that was created in an encrypted directory that hasn't had its + * encryption key added yet. Such dentries may be either positive or negative. + * + * When a filesystem is asked to create a new filename in an encrypted directory + * and the new filename's dentry is a no-key dentry, it must fail the operation + * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), + * ->rename(), and ->link(). (However, ->rename() and ->link() are already + * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) + * + * This is necessary because creating a filename requires the directory's + * encryption key, but just checking for the key on the directory inode during + * the final filesystem operation doesn't guarantee that the key was available + * during the preceding dentry lookup. And the key must have already been + * available during the dentry lookup in order for it to have been checked + * whether the filename already exists in the directory and for the new file's + * dentry not to be invalidated due to it incorrectly having the no-key flag. + * + * Return: %true if the dentry is a no-key name + */ +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NOKEY_NAME; +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -244,6 +273,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) { } +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return false; +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {

3 years, 10 months

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FAILED: patch "[PATCH] fscrypt: add fscrypt_is_nokey_name()" 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>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 159e1de201b6fca10bfec50405a3b53a561096a8 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers(a)google.com> Date: Tue, 17 Nov 2020 23:56:05 -0800 Subject: [PATCH] fscrypt: add fscrypt_is_nokey_name() It's possible to create a duplicate filename in an encrypted directory by creating a file concurrently with adding the encryption key. Specifically, sys_open(O_CREAT) (or sys_mkdir(), sys_mknod(), or sys_symlink()) can lookup the target filename while the directory's encryption key hasn't been added yet, resulting in a negative no-key dentry. The VFS then calls ->create() (or ->mkdir(), ->mknod(), or ->symlink()) because the dentry is negative. Normally, ->create() would return -ENOKEY due to the directory's key being unavailable. However, if the key was added between the dentry lookup and ->create(), then the filesystem will go ahead and try to create the file. If the target filename happens to already exist as a normal name (not a no-key name), a duplicate filename may be added to the directory. In order to fix this, we need to fix the filesystems to prevent ->create(), ->mkdir(), ->mknod(), and ->symlink() on no-key names. (->rename() and ->link() need it too, but those are already handled correctly by fscrypt_prepare_rename() and fscrypt_prepare_link().) In preparation for this, add a helper function fscrypt_is_nokey_name() that filesystems can use to do this check. Use this helper function for the existing checks that fs/crypto/ does for rename and link. Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20201118075609.120337-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..061418be4b08 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -61,7 +61,7 @@ int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, return err; /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; if (!fscrypt_has_permitted_context(dir, inode)) @@ -86,7 +86,8 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return err; /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; if (old_dir != new_dir) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..8e1d31c959bf 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -111,6 +111,35 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) dentry->d_flags &= ~DCACHE_NOKEY_NAME; } +/** + * fscrypt_is_nokey_name() - test whether a dentry is a no-key name + * @dentry: the dentry to check + * + * This returns true if the dentry is a no-key dentry. A no-key dentry is a + * dentry that was created in an encrypted directory that hasn't had its + * encryption key added yet. Such dentries may be either positive or negative. + * + * When a filesystem is asked to create a new filename in an encrypted directory + * and the new filename's dentry is a no-key dentry, it must fail the operation + * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), + * ->rename(), and ->link(). (However, ->rename() and ->link() are already + * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) + * + * This is necessary because creating a filename requires the directory's + * encryption key, but just checking for the key on the directory inode during + * the final filesystem operation doesn't guarantee that the key was available + * during the preceding dentry lookup. And the key must have already been + * available during the dentry lookup in order for it to have been checked + * whether the filename already exists in the directory and for the new file's + * dentry not to be invalidated due to it incorrectly having the no-key flag. + * + * Return: %true if the dentry is a no-key name + */ +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return dentry->d_flags & DCACHE_NOKEY_NAME; +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -244,6 +273,11 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry) { } +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) +{ + return false; +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) {

3 years, 10 months

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[PATCH AUTOSEL 4.4 01/38] locks: Fix UBSAN undefined behaviour in flock64_to_posix_lock

by Sasha Levin

From: Luo Meng <luomeng12(a)huawei.com> [ Upstream commit 16238415eb9886328a89fe7a3cb0b88c7335fe16 ] When the sum of fl->fl_start and l->l_len overflows, UBSAN shows the following warning: UBSAN: Undefined behaviour in fs/locks.c:482:29 signed integer overflow: 2 + 9223372036854775806 cannot be represented in type 'long long int' Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xe4/0x14e lib/dump_stack.c:118 ubsan_epilogue+0xe/0x81 lib/ubsan.c:161 handle_overflow+0x193/0x1e2 lib/ubsan.c:192 flock64_to_posix_lock fs/locks.c:482 [inline] flock_to_posix_lock+0x595/0x690 fs/locks.c:515 fcntl_setlk+0xf3/0xa90 fs/locks.c:2262 do_fcntl+0x456/0xf60 fs/fcntl.c:387 __do_sys_fcntl fs/fcntl.c:483 [inline] __se_sys_fcntl fs/fcntl.c:468 [inline] __x64_sys_fcntl+0x12d/0x180 fs/fcntl.c:468 do_syscall_64+0xc8/0x5a0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix it by parenthesizing 'l->l_len - 1'. Signed-off-by: Luo Meng <luomeng12(a)huawei.com> Signed-off-by: Jeff Layton <jlayton(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/locks.c b/fs/locks.c index 2c8e1e429cf7e..5cb012e4a2fc4 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -434,7 +434,7 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, if (l->l_len > 0) { if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) return -EOVERFLOW; - fl->fl_end = fl->fl_start + l->l_len - 1; + fl->fl_end = fl->fl_start + (l->l_len - 1); } else if (l->l_len < 0) { if (fl->fl_start + l->l_len < 0) -- 2.27.0

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Linux-stable-mirror December 2020