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authorZhihao Cheng <chengzhihao1@huawei.com>2024-01-08 05:41:05 +0300
committerRichard Weinberger <richard@nod.at>2024-02-25 23:40:39 +0300
commit6379b44cdcd67f5f5d986b73953e99700591edfa (patch)
tree3fcdee9d64a5cd3b312ca626e70c7b53e2808e14 /fs/ubifs
parent31a9d5f3290c5483d41c6b5c8ebc0add130da770 (diff)
downloadlinux-6379b44cdcd67f5f5d986b73953e99700591edfa.tar.xz
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/ubifs')
-rw-r--r--fs/ubifs/dir.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index e413a9cf8ee3..6b3db00d9b12 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1134,6 +1134,8 @@ 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: