[syzbot] [bluetooth?] KASAN: slab-use-after-free Read in sco_sock_connect

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 228a1157fb9f Merge tag '6.13-rc-part1-SMB3-client-fixes' o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=173469c0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2406be795e8a5f4
dashboard link: https://syzkaller.appspot.com/bug?extid=489f78df4709ac2bfdd3
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=179db6e8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/02a2c8cad502/disk-228a1157.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ad0cba81ae3f/vmlinux-228a1157.xz
kernel image: https://storage.googleapis.com/syzbot-assets/325bd791039e/bzImage-228a1157.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+489f78...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x2d90/0x3c40 kernel/locking/lockdep.c:5089
Read of size 8 at addr ffff88802e36fc20 by task syz.4.5353/17208

CPU: 0 UID: 0 PID: 17208 Comm: syz.4.5353 Not tainted 6.12.0-syzkaller-08446-g228a1157fb9f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
__lock_acquire+0x2d90/0x3c40 kernel/locking/lockdep.c:5089
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
sco_chan_add net/bluetooth/sco.c:292 [inline]
sco_connect net/bluetooth/sco.c:345 [inline]
sco_sock_connect+0x351/0xbd0 net/bluetooth/sco.c:645
__sys_connect_file+0x13e/0x1a0 net/socket.c:2055
__sys_connect+0x14f/0x170 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ec497e819
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0ec5705038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f0ec4b35fa0 RCX: 00007f0ec497e819
RDX: 0000000000000008 RSI: 0000000020000040 RDI: 0000000000000004
RBP: 00007f0ec49f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0ec4b35fa0 R15: 00007fffedcfae08
</TASK>

Allocated by task 17048:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
kmalloc_noprof include/linux/slab.h:879 [inline]
kzalloc_noprof include/linux/slab.h:1015 [inline]
sco_conn_add net/bluetooth/sco.c:199 [inline]
sco_conn_add+0xc8/0x410 net/bluetooth/sco.c:184
sco_connect net/bluetooth/sco.c:336 [inline]
sco_sock_connect+0x325/0xbd0 net/bluetooth/sco.c:645
__sys_connect_file+0x13e/0x1a0 net/socket.c:2055
__sys_connect+0x14f/0x170 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 17208:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2342 [inline]
slab_free mm/slub.c:4579 [inline]
kfree+0x14f/0x4b0 mm/slub.c:4727
sco_conn_free net/bluetooth/sco.c:97 [inline]
kref_put include/linux/kref.h:65 [inline]
sco_conn_put+0x2cd/0x4c0 net/bluetooth/sco.c:107
sco_conn_add+0x7b/0x410 net/bluetooth/sco.c:195
sco_connect net/bluetooth/sco.c:336 [inline]
sco_sock_connect+0x325/0xbd0 net/bluetooth/sco.c:645
__sys_connect_file+0x13e/0x1a0 net/socket.c:2055
__sys_connect+0x14f/0x170 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x72/0xb0 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802e36fc00
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 32 bytes inside of
freed 256-byte region [ffff88802e36fc00, ffff88802e36fd00)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2e36e
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b041b40 ffffea0001f05700 dead000000000003
raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801b041b40 ffffea0001f05700 dead000000000003
head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 00fff00000000001 ffffea0000b8db81 ffffffffffffffff 0000000000000000
head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 8168075657, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
__alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
alloc_slab_page mm/slub.c:2412 [inline]
allocate_slab mm/slub.c:2578 [inline]
new_slab+0x2c9/0x410 mm/slub.c:2631
___slab_alloc+0xdac/0x1880 mm/slub.c:3818
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
__do_kmalloc_node mm/slub.c:4263 [inline]
__kmalloc_node_noprof+0x357/0x430 mm/slub.c:4270
__kvmalloc_node_noprof+0xad/0x1a0 mm/util.c:658
v4l2_ctrl_new+0x99a/0x2090 drivers/media/v4l2-core/v4l2-ctrls-core.c:1931
v4l2_ctrl_new_std+0x1b3/0x280 drivers/media/v4l2-core/v4l2-ctrls-core.c:2068
handler_new_ref+0x828/0xc60 drivers/media/v4l2-core/v4l2-ctrls-core.c:1689
v4l2_ctrl_add_handler drivers/media/v4l2-core/v4l2-ctrls-core.c:2212 [inline]
v4l2_ctrl_add_handler+0x22a/0x310 drivers/media/v4l2-core/v4l2-ctrls-core.c:2186
vivid_create_controls+0x2eaf/0x3e00 drivers/media/test-drivers/vivid/vivid-ctrls.c:1993
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1931 [inline]
vivid_probe drivers/media/test-drivers/vivid/vivid-core.c:2093 [inline]
vivid_probe+0x47df/0xae90 drivers/media/test-drivers/vivid/vivid-core.c:2078
platform_probe+0xff/0x1f0 drivers/base/platform.c:1404
page_owner free stack trace missing

Memory state around the buggy address:
ffff88802e36fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802e36fb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802e36fc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802e36fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802e36fd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[Edward Adam Davis]

add conn should not put. timeout handler miss a put when !hcon.

#syz test

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 1b8e468d24cf..78f7bca24487 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -143,6 +143,7 @@ static void sco_sock_timeout(struct work_struct *work)
sco_conn_lock(conn);
if (!conn->hcon) {
sco_conn_unlock(conn);
+ sco_conn_put(conn);
return;
}
sk = sco_sock_hold(conn);
@@ -192,7 +193,6 @@ static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
conn->hcon = hcon;
sco_conn_unlock(conn);
}
- sco_conn_put(conn);
return conn;
}

[syzbot]

Hello,

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

Reported-by: syzbot+489f78...@syzkaller.appspotmail.com
Tested-by: syzbot+489f78...@syzkaller.appspotmail.com

Tested on:

commit: 9f16d5e6 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=101b775f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7393f07275e8e571

dashboard link: https://syzkaller.appspot.com/bug?extid=489f78df4709ac2bfdd3
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=119edee8580000

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

[Edward Adam Davis]

When adding conn, it is necessary to increase and retain the conn reference
count at the same time.

Another problem was fixed along the way, conn_put is missing when hcon is NULL
in the timeout routine.

Fixes: e6720779ae61 ("Bluetooth: SCO: Use kref to track lifetime of sco_conn")
Reported-and-tested-by: syzbot+489f78...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=489f78df4709ac2bfdd3
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 1b8e468d24cf..78f7bca24487 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -143,6 +143,7 @@ static void sco_sock_timeout(struct work_struct *work)
sco_conn_lock(conn);
if (!conn->hcon) {
sco_conn_unlock(conn);
+ sco_conn_put(conn);
return;
}
sk = sco_sock_hold(conn);
@@ -192,7 +193,6 @@ static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
conn->hcon = hcon;
sco_conn_unlock(conn);
}
- sco_conn_put(conn);
return conn;
}

--
2.43.0

[patchwork-b...@kernel.org]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.vo...@intel.com>:

On Tue, 26 Nov 2024 07:58:43 +0800 you wrote:
> When adding conn, it is necessary to increase and retain the conn reference
> count at the same time.
>
> Another problem was fixed along the way, conn_put is missing when hcon is NULL
> in the timeout routine.
>
> Fixes: e6720779ae61 ("Bluetooth: SCO: Use kref to track lifetime of sco_conn")
> Reported-and-tested-by: syzbot+489f78...@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=489f78df4709ac2bfdd3
> Signed-off-by: Edward Adam Davis <ead...@qq.com>
>

> [...]

Here is the summary with links:
- Bluetooth: SCO: remove the redundant sco_conn_put
https://git.kernel.org/bluetooth/bluetooth-next/c/ad0d88dc33bb

You are awesome, thank you!
--
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