This is a note to let you know that I've just added the patch titled
f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
f2fs-fix-to-do-sanity-check-on-last-xattr-entry-in-__f2fs_setxattr.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5598b24efaf4892741c798b425d543e4bed357a1 Mon Sep 17 00:00:00 2001
From: Chao Yu <chao@xxxxxxxxxx>
Date: Sun, 12 Dec 2021 17:16:30 +0800
Subject: f2fs: fix to do sanity check on last xattr entry in __f2fs_setxattr()
From: Chao Yu <chao@xxxxxxxxxx>
commit 5598b24efaf4892741c798b425d543e4bed357a1 upstream.
As Wenqing Liu reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215235
- Overview
page fault in f2fs_setxattr() when mount and operate on corrupted image
- Reproduce
tested on kernel 5.16-rc3, 5.15.X under root
1. unzip tmp7.zip
2. ./single.sh f2fs 7
Sometimes need to run the script several times
- Kernel dump
loop0: detected capacity change from 0 to 131072
F2FS-fs (loop0): Found nat_bits in checkpoint
F2FS-fs (loop0): Mounted with checkpoint version = 7548c2ee
BUG: unable to handle page fault for address: ffffe47bc7123f48
RIP: 0010:kfree+0x66/0x320
Call Trace:
__f2fs_setxattr+0x2aa/0xc00 [f2fs]
f2fs_setxattr+0xfa/0x480 [f2fs]
__f2fs_set_acl+0x19b/0x330 [f2fs]
__vfs_removexattr+0x52/0x70
__vfs_removexattr_locked+0xb1/0x140
vfs_removexattr+0x56/0x100
removexattr+0x57/0x80
path_removexattr+0xa3/0xc0
__x64_sys_removexattr+0x17/0x20
do_syscall_64+0x37/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is in __f2fs_setxattr(), we missed to do sanity check on
last xattr entry, result in out-of-bound memory access during updating
inconsistent xattr data of target inode.
After the fix, it can detect such xattr inconsistency as below:
F2FS-fs (loop11): inode (7) has invalid last xattr entry, entry_size: 60676
F2FS-fs (loop11): inode (8) has corrupted xattr
F2FS-fs (loop11): inode (8) has corrupted xattr
F2FS-fs (loop11): inode (8) has invalid last xattr entry, entry_size: 47736
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Wenqing Liu <wenqingliu0120@xxxxxxxxx>
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/f2fs/xattr.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -684,8 +684,17 @@ static int __f2fs_setxattr(struct inode
}
last = here;
- while (!IS_XATTR_LAST_ENTRY(last))
+ while (!IS_XATTR_LAST_ENTRY(last)) {
+ if ((void *)(last) + sizeof(__u32) > last_base_addr ||
+ (void *)XATTR_NEXT_ENTRY(last) > last_base_addr) {
+ f2fs_err(F2FS_I_SB(inode), "inode (%lu) has invalid last xattr entry, entry_size: %zu",
+ inode->i_ino, ENTRY_SIZE(last));
+ set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_FSCK);
+ error = -EFSCORRUPTED;
+ goto exit;
+ }
last = XATTR_NEXT_ENTRY(last);
+ }
newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
Patches currently in stable-queue which might be from chao@xxxxxxxxxx are
queue-5.15/f2fs-fix-to-do-sanity-check-on-last-xattr-entry-in-__f2fs_setxattr.patch
