[syzbot] [bluetooth?] KASAN: slab-out-of-bounds Read in sco_sock_setsockopt

[syzbot]

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=17e823e3180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=b71011ec0a23f4d15625
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=12155aa9180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ace2a9180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f6c04726a2ae/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/09c26ce901ea/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/134acf7f5322/bzImage-fe46a7dd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b71011...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr include/linux/sockptr.h:55 [inline]
BUG: KASAN: slab-out-of-bounds in sco_sock_setsockopt+0xc0b/0xf90 net/bluetooth/sco.c:893
Read of size 4 at addr ffff8880296aeb83 by task syz-executor142/5061

CPU: 0 PID: 5061 Comm: syz-executor142 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
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
copy_from_sockptr include/linux/sockptr.h:55 [inline]
sco_sock_setsockopt+0xc0b/0xf90 net/bluetooth/sco.c:893
do_sock_setsockopt+0x3af/0x720 net/socket.c:2311
__sys_setsockopt+0x1ae/0x250 net/socket.c:2334
__do_sys_setsockopt net/socket.c:2343 [inline]
__se_sys_setsockopt net/socket.c:2340 [inline]
__x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fe1069a9d89
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb5d99c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe1069a9d89
RDX: 0000000000000010 RSI: 0000000000000112 RDI: 0000000000000007
RBP: 0000000000000006 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 0000555584ea7338
R13: 000000000000000e R14: 0000000000000000 R15: 0000000000000000
</TASK>

Allocated by task 5061:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slub.c:3966 [inline]
__kmalloc+0x233/0x4a0 mm/slub.c:3979
kmalloc include/linux/slab.h:632 [inline]
__cgroup_bpf_run_filter_setsockopt+0xd2f/0x1040 kernel/bpf/cgroup.c:1869
do_sock_setsockopt+0x6b4/0x720 net/socket.c:2293
__sys_setsockopt+0x1ae/0x250 net/socket.c:2334
__do_sys_setsockopt net/socket.c:2343 [inline]
__se_sys_setsockopt net/socket.c:2340 [inline]
__x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75

The buggy address belongs to the object at ffff8880296aeb80
which belongs to the cache kmalloc-8 of size 8
The buggy address is located 1 bytes to the right of
allocated 2-byte region [ffff8880296aeb80, ffff8880296aeb82)

The buggy address belongs to the physical page:
page:ffffea0000a5ab80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x296ae
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888014c41280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080800080 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 18614896584, free_ts 17708736389
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0x33ea/0x3580 mm/page_alloc.c:3311
__alloc_pages+0x256/0x680 mm/page_alloc.c:4569
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmalloc_trace+0x269/0x360 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
add_sysfs_param+0x541/0x7f0 kernel/params.c:646
kernel_add_sysfs_param+0xb4/0x130 kernel/params.c:817
param_sysfs_builtin+0x16e/0x1f0 kernel/params.c:856
param_sysfs_builtin_init+0x31/0x40 kernel/params.c:990
do_one_initcall+0x238/0x830 init/main.c:1241
do_initcall_level+0x157/0x210 init/main.c:1303
do_initcalls+0x3f/0x80 init/main.c:1319
kernel_init_freeable+0x435/0x5d0 init/main.c:1550
kernel_init+0x1d/0x2a0 init/main.c:1439
page last free pid 57 tgid 57 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x95d/0xa80 mm/page_alloc.c:2346
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
vfree+0x186/0x2e0 mm/vmalloc.c:2914
delayed_vfree_work+0x56/0x80 mm/vmalloc.c:2835
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

Memory state around the buggy address:
ffff8880296aea80: 00 fc fc fc 00 fc fc fc fa fc fc fc 07 fc fc fc
ffff8880296aeb00: 07 fc fc fc fa fc fc fc 00 fc fc fc 00 fc fc fc
>ffff8880296aeb80: 02 fc fc fc 04 fc fc fc 04 fc fc fc fa fc fc fc
^
ffff8880296aec00: fa fc fc fc fa fc fc fc fa fc fc fc 00 fc fc fc
ffff8880296aec80: 00 fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
==================================================================


---
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[Edward Adam Davis]

please test oob in rfcomm_sock_setsockopt

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fe46a7dd189e

diff --git a/net/socket.c b/net/socket.c
index e5f3af49a8b6..d5b2ab6c859c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2327,6 +2327,9 @@ int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
int err, fput_needed;
struct socket *sock;

+ if (optlen < 4)
+ return -EINVAL;
+
sock = sockfd_lookup_light(fd, &err, &fput_needed);
if (!sock)
return err;

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+b71011...@syzkaller.appspotmail.com

Tested on:

commit: fe46a7dd Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=141bdfc5180000

kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=b71011ec0a23f4d15625
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14167ead180000

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

[Edward Adam Davis]

If optlen < sizeof(u32) it will trigger oob, so take the min of them.

Reported-by: syzbot+b71011...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
net/bluetooth/sco.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 43daf965a01e..815646d9e72b 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -890,7 +890,7 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname,
break;

case BT_PKT_STATUS:
- if (copy_from_sockptr(&opt, optval, sizeof(u32))) {
+ if (copy_from_sockptr(&opt, optval, min_t(int, sizeof(u32), optlen))) {
err = -EFAULT;
break;
}
--
2.43.0

[Luiz Augusto von Dentz]

Hi Edward,

https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/commit/?id=289bfd91fcf22f7864f3817acff5d8ce9fe73307


--
Luiz Augusto von Dentz