ACK: [SRU][M/J/F][PATCH 0/1] CVE-2023-52603

Manuel Diewald manuel.diewald at canonical.com
Wed Mar 27 18:29:24 UTC 2024


On Wed, Mar 27, 2024 at 12:40:27PM -0500, Bethany Jamison wrote:
> [Impact]
> 
>  In the Linux kernel, the following vulnerability has been resolved:
> 
>  UBSAN: array-index-out-of-bounds in dtSplitRoot
> 
>  Syzkaller reported the following issue:
> 
>  oop0: detected capacity change from 0 to 32768
> 
>  UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1971:9
>  index -2 is out of range for type 'struct dtslot [128]'
>  CPU: 0 PID: 3613 Comm: syz-executor270 Not tainted
>  6.0.0-syzkaller-09423-g493ffd6605b2 #0
>  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>  Google 09/22/2022
>  Call Trace:
>   <TASK>
>   __dump_stack lib/dump_stack.c:88 [inline]
>   dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
>   ubsan_epilogue lib/ubsan.c:151 [inline]
>   __ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:283
>   dtSplitRoot+0x8d8/0x1900 fs/jfs/jfs_dtree.c:1971
>   dtSplitUp fs/jfs/jfs_dtree.c:985 [inline]
>   dtInsert+0x1189/0x6b80 fs/jfs/jfs_dtree.c:863
>   jfs_mkdir+0x757/0xb00 fs/jfs/namei.c:270
>   vfs_mkdir+0x3b3/0x590 fs/namei.c:4013
>   do_mkdirat+0x279/0x550 fs/namei.c:4038
>   __do_sys_mkdirat fs/namei.c:4053 [inline]
>   __se_sys_mkdirat fs/namei.c:4051 [inline]
>   __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4051
>   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>   do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
>  RIP: 0033:0x7fcdc0113fd9
>  Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 c0 ff ff ff f7 d8 64 89 01 48
>  RSP: 002b:00007ffeb8bc67d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
>  RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcdc0113fd9
>  RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003
>  RBP: 00007fcdc00d37a0 R08: 0000000000000000 R09: 00007fcdc00d37a0
>  R10: 00005555559a72c0 R11: 0000000000000246 R12: 00000000f8008000
>  R13: 0000000000000000 R14: 00083878000000f8 R15: 0000000000000000
>   </TASK>
> 
>  The issue is caused when the value of fsi becomes less than -1.
>  The check to break the loop when fsi value becomes -1 is present
>  but syzbot was able to produce value less than -1 which cause the error.
>  This patch simply add the change for the values less than 0.
> 
>  The patch is tested via syzbot.
> 
> [Fix]
> 
> Mantic:	Clean cherry-pick
> Jammy:	Mantic patch applied cleanly
> Focal:	Mantic patch applied cleanly
> Bionic:	fix sent to esm ML
> Xenial:	fix sent to esm ML
> Trusty:	not going to be fixed by us
> 
> [Test Case]
> 
> Compile and boot tested.
> 
> [Where problems could occur]
> 
> This affects those who use jfs, issues could occur when spliting
> the decision tree from the root resulting in overwritting the tree, 
> but this fix is low risk since the change is very simple.
> 
> Osama Muhammad (1):
>   UBSAN: array-index-out-of-bounds in dtSplitRoot
> 
>  fs/jfs/jfs_dtree.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> -- 
> 2.34.1
> 
> 
> -- 
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> kernel-team at lists.ubuntu.com
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Acked-by: Manuel Diewald <manuel.diewald at canonical.com>

-- 
 Manuel



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