[syzbot] KASAN: slab-out-of-bounds Read in sk_psock_get

From: syzbot
Date: Wed Aug 25 2021 - 14:42:29 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 12d125b4574b stmmac: Revert "stmmac: align RX buffers"
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=17c6e38d300000
kernel config: https://syzkaller.appspot.com/x/.config?x=96f0602203250753
dashboard link: https://syzkaller.appspot.com/bug?extid=1fa91bcd05206ff8cbb5
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12618c05300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e60d05300000

The issue was bisected to:

commit 130b392c6cd6b2aed1b7eb32253d4920babb4891
Author: Dave Watson <davejwatson@xxxxxx>
Date: Wed Jan 30 21:58:31 2019 +0000

net: tls: Add tls 1.3 support

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13694355300000
final oops: https://syzkaller.appspot.com/x/report.txt?x=10e94355300000
console output: https://syzkaller.appspot.com/x/log.txt?x=17694355300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1fa91bcd05206ff8cbb5@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 130b392c6cd6 ("net: tls: Add tls 1.3 support")

==================================================================
BUG: KASAN: slab-out-of-bounds in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: slab-out-of-bounds in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
BUG: KASAN: slab-out-of-bounds in refcount_read include/linux/refcount.h:147 [inline]
BUG: KASAN: slab-out-of-bounds in __refcount_add_not_zero include/linux/refcount.h:152 [inline]
BUG: KASAN: slab-out-of-bounds in __refcount_inc_not_zero include/linux/refcount.h:227 [inline]
BUG: KASAN: slab-out-of-bounds in refcount_inc_not_zero include/linux/refcount.h:245 [inline]
BUG: KASAN: slab-out-of-bounds in sk_psock_get+0x123/0x410 include/linux/skmsg.h:449
Read of size 4 at addr ffff888011d9c2b8 by task syz-executor654/8452

CPU: 0 PID: 8452 Comm: syz-executor654 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read include/linux/instrumented.h:71 [inline]
atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
refcount_read include/linux/refcount.h:147 [inline]
__refcount_add_not_zero include/linux/refcount.h:152 [inline]
__refcount_inc_not_zero include/linux/refcount.h:227 [inline]
refcount_inc_not_zero include/linux/refcount.h:245 [inline]
sk_psock_get+0x123/0x410 include/linux/skmsg.h:449
tls_sw_recvmsg+0x19e/0x1670 net/tls/tls_sw.c:1761
inet_recvmsg+0x11b/0x5e0 net/ipv4/af_inet.c:852
sock_recvmsg_nosec net/socket.c:943 [inline]
sock_recvmsg net/socket.c:961 [inline]
sock_recvmsg net/socket.c:957 [inline]
____sys_recvmsg+0x2c4/0x600 net/socket.c:2611
___sys_recvmsg+0x127/0x200 net/socket.c:2653
do_recvmmsg+0x24d/0x6d0 net/socket.c:2747
__sys_recvmmsg net/socket.c:2826 [inline]
__do_sys_recvmmsg net/socket.c:2849 [inline]
__se_sys_recvmmsg net/socket.c:2842 [inline]
__x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2842
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43f4f9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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:00007ffd2e991cd8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f4f9
RDX: 000000000000000a RSI: 00000000200030c0 RDI: 0000000000000005
RBP: 00000000004034e0 R08: 0000000000000000 R09: 0000000000400488
R10: 0000000000010000 R11: 0000000000000246 R12: 0000000000403570
R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488

Allocated by task 8452:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x84/0xa0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:2959 [inline]
slab_alloc mm/slub.c:2967 [inline]
kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2972
kmem_cache_zalloc include/linux/slab.h:711 [inline]
kcm_attach net/kcm/kcmsock.c:1404 [inline]
kcm_attach_ioctl net/kcm/kcmsock.c:1489 [inline]
kcm_ioctl+0x7f1/0x1180 net/kcm/kcmsock.c:1695
sock_do_ioctl+0xcb/0x2d0 net/socket.c:1094
sock_ioctl+0x477/0x6a0 net/socket.c:1221
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
insert_work+0x48/0x370 kernel/workqueue.c:1332
__queue_work+0x5c1/0xed0 kernel/workqueue.c:1498
queue_work_on+0xee/0x110 kernel/workqueue.c:1525
kcm_attach net/kcm/kcmsock.c:1465 [inline]
kcm_attach_ioctl net/kcm/kcmsock.c:1489 [inline]
kcm_ioctl+0xede/0x1180 net/kcm/kcmsock.c:1695
sock_do_ioctl+0xcb/0x2d0 net/socket.c:1094
sock_ioctl+0x477/0x6a0 net/socket.c:1221
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888011d9c000
which belongs to the cache kcm_psock_cache of size 568
The buggy address is located 128 bytes to the right of
568-byte region [ffff888011d9c000, ffff888011d9c238)
The buggy address belongs to the page:
page:ffffea0000476700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11d9c
head:ffffea0000476700 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff8881478543c0
raw: 0000000000000000 0000000080170017 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 8452, ts 72409999814, free_ts 72272935271
prep_new_page mm/page_alloc.c:2436 [inline]
get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244
alloc_slab_page mm/slub.c:1691 [inline]
allocate_slab+0x32e/0x4b0 mm/slub.c:1831
new_slab mm/slub.c:1894 [inline]
new_slab_objects mm/slub.c:2640 [inline]
___slab_alloc+0x4ba/0x820 mm/slub.c:2803
__slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2843
slab_alloc_node mm/slub.c:2925 [inline]
slab_alloc mm/slub.c:2967 [inline]
kmem_cache_alloc+0x3e1/0x4a0 mm/slub.c:2972
kmem_cache_zalloc include/linux/slab.h:711 [inline]
kcm_attach net/kcm/kcmsock.c:1404 [inline]
kcm_attach_ioctl net/kcm/kcmsock.c:1489 [inline]
kcm_ioctl+0x7f1/0x1180 net/kcm/kcmsock.c:1695
sock_do_ioctl+0xcb/0x2d0 net/socket.c:1094
sock_ioctl+0x477/0x6a0 net/socket.c:1221
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1346 [inline]
free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
free_unref_page_prepare mm/page_alloc.c:3332 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3411
__put_page+0xf9/0x3f0 mm/swap.c:127
put_page include/linux/mm.h:1246 [inline]
__skb_frag_unref include/linux/skbuff.h:3102 [inline]
skb_release_data+0x49d/0x790 net/core/skbuff.c:671
skb_release_all net/core/skbuff.c:741 [inline]
__kfree_skb net/core/skbuff.c:755 [inline]
consume_skb net/core/skbuff.c:911 [inline]
consume_skb+0xc2/0x160 net/core/skbuff.c:905
unix_stream_read_generic+0x15a2/0x19e0 net/unix/af_unix.c:2460
unix_stream_recvmsg+0xb1/0xf0 net/unix/af_unix.c:2518
sock_recvmsg_nosec net/socket.c:943 [inline]
sock_recvmsg net/socket.c:961 [inline]
sock_recvmsg net/socket.c:957 [inline]
sock_read_iter+0x33c/0x470 net/socket.c:1034
call_read_iter include/linux/fs.h:2108 [inline]
new_sync_read+0x5b7/0x6e0 fs/read_write.c:415
vfs_read+0x35c/0x570 fs/read_write.c:496
ksys_read+0x1ee/0x250 fs/read_write.c:634
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Memory state around the buggy address:
ffff888011d9c180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888011d9c200: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
>ffff888011d9c280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888011d9c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888011d9c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

Next message: Dave Hansen: "Re: [PATCH v2] x86/mm: fix kern_addr_valid to cope with existing but not present entries"
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