diff options
author | Eric Biggers <ebiggers@google.com> | 2022-11-05 02:38:00 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-11-10 20:14:25 +0300 |
commit | 29997a6fa60de1de2fa0de471e7652efa6e95868 (patch) | |
tree | b822e7c8561645012d9917a7268891425877ca52 | |
parent | 391cceee6d435e616f68631e68f5b32d480b1e67 (diff) | |
download | linux-29997a6fa60de1de2fa0de471e7652efa6e95868.tar.xz |
fscrypt: fix keyring memory leak on mount failure
commit ccd30a476f8e864732de220bd50e6f372f5ebcab upstream.
Commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for
fscrypt_master_key") moved the keyring destruction from __put_super() to
generic_shutdown_super() so that the filesystem's block device(s) are
still available. Unfortunately, this causes a memory leak in the case
where a mount is attempted with the test_dummy_encryption mount option,
but the mount fails after the option has already been processed.
To fix this, attempt the keyring destruction in both places.
Reported-by: syzbot+104c2a89561289cec13e@syzkaller.appspotmail.com
Fixes: d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20221011213838.209879-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | fs/crypto/keyring.c | 17 | ||||
-rw-r--r-- | fs/super.c | 3 | ||||
-rw-r--r-- | include/linux/fscrypt.h | 4 |
3 files changed, 15 insertions, 9 deletions
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index 175b071beaf8..02f8bf8bd54d 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -202,14 +202,19 @@ static int allocate_filesystem_keyring(struct super_block *sb) } /* - * This is called at unmount time to release all encryption keys that have been - * added to the filesystem, along with the keyring that contains them. + * Release all encryption keys that have been added to the filesystem, along + * with the keyring that contains them. * - * Note that besides clearing and freeing memory, this might need to evict keys - * from the keyslots of an inline crypto engine. Therefore, this must be called - * while the filesystem's underlying block device(s) are still available. + * This is called at unmount time. The filesystem's underlying block device(s) + * are still available at this time; this is important because after user file + * accesses have been allowed, this function may need to evict keys from the + * keyslots of an inline crypto engine, which requires the block device(s). + * + * This is also called when the super_block is being freed. This is needed to + * avoid a memory leak if mounting fails after the "test_dummy_encryption" + * option was processed, as in that case the unmount-time call isn't made. */ -void fscrypt_sb_delete(struct super_block *sb) +void fscrypt_destroy_keyring(struct super_block *sb) { struct fscrypt_keyring *keyring = sb->s_master_keys; size_t i; diff --git a/fs/super.c b/fs/super.c index beee3e1b4c29..7629f9dd031c 100644 --- a/fs/super.c +++ b/fs/super.c @@ -293,6 +293,7 @@ static void __put_super(struct super_block *s) WARN_ON(s->s_inode_lru.node); WARN_ON(!list_empty(&s->s_mounts)); security_sb_free(s); + fscrypt_destroy_keyring(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); call_rcu(&s->rcu, destroy_super_rcu); @@ -453,7 +454,7 @@ void generic_shutdown_super(struct super_block *sb) evict_inodes(sb); /* only nonzero refcount inodes can have marks */ fsnotify_sb_delete(sb); - fscrypt_sb_delete(sb); + fscrypt_destroy_keyring(sb); if (sb->s_dio_done_wq) { destroy_workqueue(sb->s_dio_done_wq); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 23d3ea47f764..d0bc66fae7e0 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -193,7 +193,7 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) } /* keyring.c */ -void fscrypt_sb_delete(struct super_block *sb); +void fscrypt_destroy_keyring(struct super_block *sb); int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg); int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg); @@ -380,7 +380,7 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) } /* keyring.c */ -static inline void fscrypt_sb_delete(struct super_block *sb) +static inline void fscrypt_destroy_keyring(struct super_block *sb) { } |