* [syzbot] [nilfs?] UBSAN: array-index-out-of-bounds in nilfs_add_link
@ 2024-04-15 10:09 syzbot
2024-04-15 18:20 ` [PATCH] nilfs2: Fix OOB in nilfs_set_de_type Ryusuke Konishi
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2024-04-15 10:09 UTC (permalink / raw
To: konishi.ryusuke, linux-fsdevel, linux-kernel, linux-nilfs,
syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1777792b180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=2e22057de05b9f3b30d8
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1176600b180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15141b43180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/72ab73815344/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d6d6b0d7071/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48e275e5478b/bzImage-fe46a7dd.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/de3bc2f4acaf/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e22057de05b9f3b30d8@syzkaller.appspotmail.com
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/nilfs2/dir.c:257:18
index 15 is out of range for type 'unsigned char[15]'
CPU: 0 PID: 5057 Comm: syz-executor165 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:415
nilfs_set_de_type fs/nilfs2/dir.c:257 [inline]
nilfs_add_link+0xb39/0xb80 fs/nilfs2/dir.c:501
nilfs_link+0x136/0x220 fs/nilfs2/namei.c:192
vfs_link+0x4f5/0x690 fs/namei.c:4608
do_linkat+0x356/0x760 fs/namei.c:4679
__do_sys_linkat fs/namei.c:4707 [inline]
__se_sys_linkat fs/namei.c:4704 [inline]
__x64_sys_linkat+0xdd/0xf0 fs/namei.c:4704
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f0624efc679
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff6dc40a98 EFLAGS: 00000246 ORIG_RAX: 0000000000000109
RAX: ffffffffffffffda RBX: 00007fff6dc40c68 RCX: 00007f0624efc679
RDX: 0000000000000004 RSI: 0000000020000180 RDI: 0000000000000004
RBP: 00007f0624f70610 R08: 0000000000000000 R09: 00007fff6dc40c68
R10: 0000000020000640 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff6dc40c58 R14: 0000000000000001 R15: 0000000000000001
</TASK>
---[ end trace ]---
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH] nilfs2: Fix OOB in nilfs_set_de_type
2024-04-15 10:09 [syzbot] [nilfs?] UBSAN: array-index-out-of-bounds in nilfs_add_link syzbot
@ 2024-04-15 18:20 ` Ryusuke Konishi
0 siblings, 0 replies; 2+ messages in thread
From: Ryusuke Konishi @ 2024-04-15 18:20 UTC (permalink / raw
To: Andrew Morton
Cc: linux-nilfs, syzbot, syzkaller-bugs, Jeongjun Park, linux-kernel,
linux-fsdevel
From: Jeongjun Park <aha310510@gmail.com>
The size of the nilfs_type_by_mode array in the fs/nilfs2/dir.c file is
defined as "S_IFMT >> S_SHIFT", but the nilfs_set_de_type() function,
which uses this array, specifies the index to read from the array in the
same way as "(mode & S_IFMT) >> S_SHIFT".
static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode
*inode)
{
umode_t mode = inode->i_mode;
de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; // oob
}
However, when the index is determined this way, an out-of-bounds (OOB)
error occurs by referring to an index that is 1 larger than the array
size when the condition "mode & S_IFMT == S_IFMT" is satisfied.
Therefore, a patch to resize the nilfs_type_by_mode array should be
applied to prevent OOB errors.
Reported-by: syzbot+2e22057de05b9f3b30d8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2e22057de05b9f3b30d8
Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: stable@vger.kernel.org
---
Hi Andrew, please apply this as a bugfix.
This patch from Jeongjun fixes an array out-of-bounds access reported
by syzbot that can occur for filesystem images containing corrupted
directory inodes.
Thanks,
Ryusuke Konishi
fs/nilfs2/dir.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
index bc846b904b68..aee40db7a036 100644
--- a/fs/nilfs2/dir.c
+++ b/fs/nilfs2/dir.c
@@ -240,7 +240,7 @@ nilfs_filetype_table[NILFS_FT_MAX] = {
#define S_SHIFT 12
static unsigned char
-nilfs_type_by_mode[S_IFMT >> S_SHIFT] = {
+nilfs_type_by_mode[(S_IFMT >> S_SHIFT) + 1] = {
[S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = NILFS_FT_DIR,
[S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV,
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2024-04-15 18:20 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-04-15 10:09 [syzbot] [nilfs?] UBSAN: array-index-out-of-bounds in nilfs_add_link syzbot
2024-04-15 18:20 ` [PATCH] nilfs2: Fix OOB in nilfs_set_de_type Ryusuke Konishi
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).