Zhihao Cheng 17be0ede8a ubifs: ubifs_symlink: Fix memleak of inode->i_link in error path
commit 1e022216dcd248326a5bb95609d12a6815bca4e2 upstream.

For error handling path in ubifs_symlink(), inode will be marked as
bad first, then iput() is invoked. If inode->i_link is initialized by
fscrypt_encrypt_symlink() in encryption scenario, inode->i_link won't
be freed by callchain ubifs_free_inode -> fscrypt_free_inode in error
handling path, because make_bad_inode() has changed 'inode->i_mode' as
'S_IFREG'.
Following kmemleak is easy to be reproduced by injecting error in
ubifs_jnl_update() when doing symlink in encryption scenario:
 unreferenced object 0xffff888103da3d98 (size 8):
  comm "ln", pid 1692, jiffies 4294914701 (age 12.045s)
  backtrace:
   kmemdup+0x32/0x70
   __fscrypt_encrypt_symlink+0xed/0x1c0
   ubifs_symlink+0x210/0x300 [ubifs]
   vfs_symlink+0x216/0x360
   do_symlinkat+0x11a/0x190
   do_syscall_64+0x3b/0xe0
There are two ways fixing it:
 1. Remove make_bad_inode() in error handling path. We can do that
    because ubifs_evict_inode() will do same processes for good
    symlink inode and bad symlink inode, for inode->i_nlink checking
    is before is_bad_inode().
 2. Free inode->i_link before marking inode bad.
Method 2 is picked, it has less influence, personally, I think.

Cc: stable@vger.kernel.org
Fixes: 2c58d548f570 ("fscrypt: cache decrypted symlink target in ->i_link")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-31 16:18:56 -08:00
..
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-28 11:39:14 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-28 09:31:32 -07:00
2023-08-28 11:04:18 -07:00
2023-08-28 10:17:14 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 17:45:22 -04:00
2023-08-29 20:21:42 -07:00
2024-01-15 18:57:06 +01:00
2023-08-31 12:07:34 -05:00
2023-08-29 20:21:42 -07:00
2023-10-19 09:10:18 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
\n
2023-08-30 12:10:50 -07:00
2023-08-29 20:21:42 -07:00
2023-08-28 09:31:32 -07:00
2023-08-28 11:59:52 -07:00
2023-08-28 10:17:14 -07:00
2023-06-28 20:35:21 -07:00
2023-06-26 09:50:21 -07:00
2023-07-26 14:56:07 +02:00
2023-08-08 19:36:51 +02:00
2023-08-28 10:17:14 -07:00
2023-08-21 13:46:25 -07:00
2023-08-14 18:48:02 +02:00
2023-08-29 20:21:42 -07:00
2023-08-29 20:21:42 -07:00
2023-08-19 12:12:12 +02:00
2023-08-31 15:32:18 -07:00
2023-08-02 09:13:09 -06:00
2023-07-13 10:28:04 +02:00
2023-08-15 08:32:45 +02:00
2023-08-31 12:47:15 +02:00