Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
jfs: reject on-disk inodes of an unsupported type
Syzbot has reported the following BUG:
kernel BUG at fs/inode.c:668!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 3 UID: 0 PID: 139 Comm: jfsCommit Not tainted 6.12.0-rc4-syzkaller-00085-g4e46774408d9 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
RIP: 0010:clear_inode+0x168/0x190
Code: 4c 89 f7 e8 ba fe e5 ff e9 61 ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 7c c1 4c 89 f7 e8 90 ff e5 ff eb b7
0b e8 01 5d 7f ff 90 0f 0b e8 f9 5c 7f ff 90 0f 0b e8 f1 5c 7f
RSP: 0018:ffffc900027dfae8 EFLAGS: 00010093
RAX: ffffffff82157a87 RBX: 0000000000000001 RCX: ffff888104d4b980
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900027dfc90 R08: ffffffff82157977 R09: fffff520004fbf38
R10: dffffc0000000000 R11: fffff520004fbf38 R12: dffffc0000000000
R13: ffff88811315bc00 R14: ffff88811315bda8 R15: ffff88811315bb80
FS: 0000000000000000(0000) GS:ffff888135f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005565222e0578 CR3: 0000000026ef0000 CR4: 00000000000006f0
Call Trace:
This happens when ‘clear_inode()’ makes an attempt to finalize an underlying JFS inode of unknown type. According to JFS layout description from https://jfs.sourceforge.net/project/pub/jfslayout.pdf, inode types from 5 to 15 are reserved for future extensions and should not be encountered on a valid filesystem. So add an extra check for valid inode type in ‘copy_from_dinode()’.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux-hwe @ 4.15.0 (+13 more)
In the Linux kernel, the following vulnerability has been resolved:
jfs: reject on-disk inodes of an unsupported type
Syzbot has reported the following BUG:
kernel BUG at fs/inode.c:668!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 3 UID: 0 PID: 139 Comm: jfsCommit Not tainted 6.12.0-rc4-syzkaller-00085-g4e46774408d9 #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
RIP: 0010:clear_inode+0x168/0x190
Code: 4c 89 f7 e8 ba fe e5 ff e9 61 ff ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 7c c1 4c 89 f7 e8 90 ff e5 ff eb b7
0b e8 01 5d 7f ff 90 0f 0b e8 f9 5c 7f ff 90 0f 0b e8 f1 5c 7f
RSP: 0018:ffffc900027dfae8 EFLAGS: 00010093
RAX: ffffffff82157a87 RBX: 0000000000000001 RCX: ffff888104d4b980
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900027dfc90 R08: ffffffff82157977 R09: fffff520004fbf38
R10: dffffc0000000000 R11: fffff520004fbf38 R12: dffffc0000000000
R13: ffff88811315bc00 R14: ffff88811315bda8 R15: ffff88811315bb80
FS: 0000000000000000(0000) GS:ffff888135f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005565222e0578 CR3: 0000000026ef0000 CR4: 00000000000006f0
Call Trace:
This happens when ‘clear_inode()’ makes an attempt to finalize an underlying JFS inode of unknown type. According to JFS layout description from https://jfs.sourceforge.net/project/pub/jfslayout.pdf, inode types from 5 to 15 are reserved for future extensions and should not be encountered on a valid filesystem. So add an extra check for valid inode type in ‘copy_from_dinode()’.