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| author | Zhihao Cheng <chengzhihao1@huawei.com> | 2023-12-22 09:54:46 +0100 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2024-01-06 23:34:56 +0100 |
| commit | 1e022216dcd248326a5bb95609d12a6815bca4e2 (patch) | |
| tree | b65775e229863584ec927b4fc0acb3cf020149f3 /fs | |
| parent | ubifs: Check @c->dirty_[n|p]n_cnt and @c->nroot state under @c->lp_mutex (diff) | |
| download | linux-1e022216dcd248326a5bb95609d12a6815bca4e2.tar.xz linux-1e022216dcd248326a5bb95609d12a6815bca4e2.zip | |
ubifs: ubifs_symlink: Fix memleak of inode->i_link in error path
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ubifs/dir.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 3b13c648d490..e413a9cf8ee3 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -1234,6 +1234,8 @@ out_cancel: dir_ui->ui_size = dir->i_size; mutex_unlock(&dir_ui->ui_mutex); out_inode: + /* Free inode->i_link before inode is marked as bad. */ + fscrypt_free_inode(inode); make_bad_inode(inode); iput(inode); out_fname: |