[syzbot] [reiserfs?] general protection fault in reiserfs_xattr_set

[syzbot] [reiserfs?] general protection fault in reiserfs_xattr_set

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    453f5db0619e Merge tag 'trace-v6.7-rc7' of git://git.kerne..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=172207cee80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7bcb8f62f1e2c3e
dashboard link: https://syzkaller.appspot.com/bug?extid=74dce9511a59ad67a492
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1534af31e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1512b9a1e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d4df4c41f20/disk-453f5db0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e858c1c82b6d/vmlinux-453f5db0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/39c3d125719d/bzImage-453f5db0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/519b891d4149/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+74dce9511a59ad67a492@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
CPU: 0 PID: 6365 Comm: syz-executor145 Not tainted 6.7.0-rc7-syzkaller-00049-g453f5db0619e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
RIP: 0010:d_really_is_negative include/linux/dcache.h:467 [inline]
RIP: 0010:reiserfs_xattr_jcreate_nblocks fs/reiserfs/xattr.h:79 [inline]
RIP: 0010:reiserfs_xattr_set+0x2d4/0x5c0 fs/reiserfs/xattr.c:626
Code: e9 03 80 3c 11 00 0f 85 e0 02 00 00 4d 8b a4 24 a0 05 00 00 48 ba 00 00 00 00 00 fc ff df 49 8d 7c 24 68 48 89 f9 48 c1 e9 03 <80> 3c 11 00 0f 85 cc 02 00 00 49 83 7c 24 68 00 0f 84 eb 01 00 00
RSP: 0018:ffffc9000a22f8f0 EFLAGS: 00010212
RAX: 000000000000006c RBX: ffff88805d650190 RCX: 000000000000000d
RDX: dffffc0000000000 RSI: ffffffff822cd9af RDI: 0000000000000068
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
R13: ffff88801c4e0000 R14: ffff88805d6501b8 R15: 0000000000000036
FS:  00007fd868e9f6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd868e9fd58 CR3: 0000000079dbb000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 security_set+0x85/0xb0 fs/reiserfs/xattr_security.c:32
 __vfs_setxattr+0x173/0x1d0 fs/xattr.c:201
 __vfs_setxattr_noperm+0x127/0x5e0 fs/xattr.c:235
 __vfs_setxattr_locked+0x17e/0x250 fs/xattr.c:296
 vfs_setxattr+0x146/0x350 fs/xattr.c:322
 do_setxattr+0x142/0x170 fs/xattr.c:630
 setxattr+0x159/0x170 fs/xattr.c:653
 __do_sys_fsetxattr fs/xattr.c:709 [inline]
 __se_sys_fsetxattr fs/xattr.c:698 [inline]
 __x64_sys_fsetxattr+0x25e/0x310 fs/xattr.c:698
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fd868f03e99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd868e9f228 EFLAGS: 00000246 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 00007fd868f8c6d8 RCX: 00007fd868f03e99
RDX: 0000000020000400 RSI: 00000000200003c0 RDI: 0000000000000004
RBP: 00007fd868f8c6d0 R08: 0000000000000000 R09: 00007fd868e9f6c0
R10: 0000000000000002 R11: 0000000000000246 R12: 00007fd868f58073
R13: 00007fd868f5806b R14: 3404af7c435ebb98 R15: 00007ffd907624e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:d_really_is_negative include/linux/dcache.h:467 [inline]
RIP: 0010:reiserfs_xattr_jcreate_nblocks fs/reiserfs/xattr.h:79 [inline]
RIP: 0010:reiserfs_xattr_set+0x2d4/0x5c0 fs/reiserfs/xattr.c:626
Code: e9 03 80 3c 11 00 0f 85 e0 02 00 00 4d 8b a4 24 a0 05 00 00 48 ba 00 00 00 00 00 fc ff df 49 8d 7c 24 68 48 89 f9 48 c1 e9 03 <80> 3c 11 00 0f 85 cc 02 00 00 49 83 7c 24 68 00 0f 84 eb 01 00 00
RSP: 0018:ffffc9000a22f8f0 EFLAGS: 00010212
RAX: 000000000000006c RBX: ffff88805d650190 RCX: 000000000000000d
RDX: dffffc0000000000 RSI: ffffffff822cd9af RDI: 0000000000000068
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
R13: ffff88801c4e0000 R14: ffff88805d6501b8 R15: 0000000000000036
FS:  00007fd868e9f6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd860e9f000 CR3: 0000000079dbb000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	80 3c 11 00          	cmpb   $0x0,(%rcx,%rdx,1)
   4:	0f 85 e0 02 00 00    	jne    0x2ea
   a:	4d 8b a4 24 a0 05 00 	mov    0x5a0(%r12),%r12
  11:	00
  12:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  19:	fc ff df
  1c:	49 8d 7c 24 68       	lea    0x68(%r12),%rdi
  21:	48 89 f9             	mov    %rdi,%rcx
  24:	48 c1 e9 03          	shr    $0x3,%rcx
* 28:	80 3c 11 00          	cmpb   $0x0,(%rcx,%rdx,1) <-- trapping instruction
  2c:	0f 85 cc 02 00 00    	jne    0x2fe
  32:	49 83 7c 24 68 00    	cmpq   $0x0,0x68(%r12)
  38:	0f 84 eb 01 00 00    	je     0x229


---
This report is generated by a bot. It may contain errors.
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syzbot engineers can be reached at syzkaller@googlegroups.com.

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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:
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#syz undup

Re: [syzbot] [reiserfs?] general protection fault in reiserfs_xattr_set

[Edward Adam Davis]

please test null ptr deref in reiserfs_xattr_set

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 453f5db0619e

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 998035a6388e..00fd8f747394 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -618,6 +618,9 @@ int reiserfs_xattr_set(struct inode *inode, const char *name,
 	int error, error2;
 	size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
 
+	if (!reiserfs_xattrs_initialized(inode->i_sb))
+		return -EOPNOTSUPP;
+
 	/* Check before we start a transaction and then do nothing. */
 	if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
 		return -EOPNOTSUPP;

Re: [syzbot] [reiserfs?] general protection fault in reiserfs_xattr_set

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+74dce9511a59ad67a492@syzkaller.appspotmail.com

Tested on:

commit:         453f5db0 Merge tag 'trace-v6.7-rc7' of git://git.kerne..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=110b4145e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7bcb8f62f1e2c3e
dashboard link: https://syzkaller.appspot.com/bug?extid=74dce9511a59ad67a492
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17f34145e80000

Note: testing is done by a robot and is best-effort only.

[PATCH] reiserfs: fix null ptr deref in reiserfs_xattr_set

[Edward Adam Davis]

Before performing any xattr settings, it is necessary to first confirm that both
xattr_root and priv_root are valid.

Reported-and-tested-by: syzbot+74dce9511a59ad67a492@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com
---
 fs/reiserfs/xattr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 998035a6388e..00fd8f747394 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -618,6 +618,9 @@ int reiserfs_xattr_set(struct inode *inode, const char *name,
 	int error, error2;
 	size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
 
+	if (!reiserfs_xattrs_initialized(inode->i_sb))
+		return -EOPNOTSUPP;
+
 	/* Check before we start a transaction and then do nothing. */
 	if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
 		return -EOPNOTSUPP;
-- 
2.43.0

Re: [syzbot] [reiserfs?] general protection fault in reiserfs_xattr_set

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <jack@suse.cz>
Date:   Wed Nov 1 17:43:10 2023 +0000

    fs: Block writes to mounted block devices

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16fc31de180000
start commit:   453f5db0619e Merge tag 'trace-v6.7-rc7' of git://git.kerne..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7bcb8f62f1e2c3e
dashboard link: https://syzkaller.appspot.com/bug?extid=74dce9511a59ad67a492
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1534af31e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1512b9a1e80000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs: Block writes to mounted block devices

For information about bisection process see: https://goo.gl/tpsmEJ#bisection