[syzbot] [crypto?] KASAN: slab-out-of-bounds Write in crypto_sha3_final (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ae230642190a Merge branch 'af_unix-followup-fixes-for-so_p..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11d7cc7f280000
kernel config: https://syzkaller.appspot.com/x/.config?x=c9bf1936936ca698
dashboard link: https://syzkaller.appspot.com/bug?extid=e436ef6c393283630f64
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8c060db03f09/disk-ae230642.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1b9b937ece91/vmlinux-ae230642.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0c7eb1c82bf0/bzImage-ae230642.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e436ef...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in crypto_sha3_final+0x5e3/0x650 crypto/sha3_generic.c:220
Write of size 1 at addr ffff88802edbd4e3 by task syz-executor.4/14380

CPU: 0 PID: 14380 Comm: syz-executor.4 Not tainted 6.4.0-rc7-syzkaller-01948-gae230642190a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
crypto_sha3_final+0x5e3/0x650 crypto/sha3_generic.c:220
shash_final_unaligned+0x154/0x220 crypto/shash.c:157
shash_finup_unaligned+0x5b/0x70 crypto/shash.c:191
crypto_shash_finup+0xdc/0x160 crypto/shash.c:212
shash_ahash_finup+0xdf/0x3a0 crypto/shash.c:333
crypto_ahash_op crypto/ahash.c:303 [inline]
crypto_ahash_op crypto/ahash.c:292 [inline]
crypto_ahash_finup+0xed/0x1e0 crypto/ahash.c:332
hash_sendmsg+0x9d0/0x1150 crypto/algif_hash.c:149
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:747
sock_write_iter+0x295/0x3d0 net/socket.c:1128
call_write_iter include/linux/fs.h:1868 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x945/0xd50 fs/read_write.c:584
ksys_write+0x1ec/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f81fd88c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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:00007f81fe5e8168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f81fd9ac120 RCX: 00007f81fd88c389
RDX: 000000000000010f RSI: 0000000020000300 RDI: 0000000000000006
RBP: 00007f81fd8d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff1397ccff R14: 00007f81fe5e8300 R15: 0000000000022000
</TASK>

Allocated by task 14377:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
____kasan_kmalloc mm/kasan/common.c:333 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:196 [inline]
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x5e/0x190 mm/slab_common.c:979
kmalloc include/linux/slab.h:563 [inline]
sock_kmalloc+0xb2/0x100 net/core/sock.c:2683
hash_accept_parent_nokey+0x54/0x2e0 crypto/algif_hash.c:416
hash_accept_parent+0x60/0x80 crypto/algif_hash.c:443
af_alg_accept+0x172/0x5d0 crypto/af_alg.c:436
do_accept+0x380/0x510 net/socket.c:1871
__sys_accept4_file net/socket.c:1912 [inline]
__sys_accept4+0x9a/0x120 net/socket.c:1942
__do_sys_accept net/socket.c:1959 [inline]
__se_sys_accept net/socket.c:1956 [inline]
__x64_sys_accept+0x75/0xb0 net/socket.c:1956
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:491
__call_rcu_common.constprop.0+0x99/0x7e0 kernel/rcu/tree.c:2627
netlink_release+0xcde/0x1e40 net/netlink/af_netlink.c:828
__sock_release+0xcd/0x290 net/socket.c:653
sock_close+0x1c/0x20 net/socket.c:1385
__fput+0x27c/0xa90 fs/file_table.c:321
task_work_run+0x16f/0x270 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xaa3/0x29b0 kernel/exit.c:874
do_group_exit+0xd4/0x2a0 kernel/exit.c:1024
__do_sys_exit_group kernel/exit.c:1035 [inline]
__se_sys_exit_group kernel/exit.c:1033 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1033
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
__kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:491
__call_rcu_common.constprop.0+0x99/0x7e0 kernel/rcu/tree.c:2627
netlink_release+0xcde/0x1e40 net/netlink/af_netlink.c:828
__sock_release+0xcd/0x290 net/socket.c:653
sock_close+0x1c/0x20 net/socket.c:1385
__fput+0x27c/0xa90 fs/file_table.c:321
task_work_run+0x16f/0x270 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xaa3/0x29b0 kernel/exit.c:874
do_group_exit+0xd4/0x2a0 kernel/exit.c:1024
__do_sys_exit_group kernel/exit.c:1035 [inline]
__se_sys_exit_group kernel/exit.c:1033 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1033
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88802edbd000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 123 bytes to the right of
allocated 1128-byte region [ffff88802edbd000, ffff88802edbd468)

The buggy address belongs to the physical page:
page:ffffea0000bb6e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88802edb9000 pfn:0x2edb8
head:ffffea0000bb6e00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000010200 ffff888012442000 ffffea0001df1e00 dead000000000002
raw: ffff88802edb9000 0000000080080007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5043, tgid 5043 (syz-executor.4), ts 168507470584, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1731
prep_new_page mm/page_alloc.c:1738 [inline]
get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3502
__alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4768
alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279
alloc_slab_page mm/slub.c:1851 [inline]
allocate_slab+0x25f/0x390 mm/slub.c:1998
new_slab mm/slub.c:2051 [inline]
___slab_alloc+0xa91/0x1400 mm/slub.c:3192
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3291
__slab_alloc_node mm/slub.c:3344 [inline]
slab_alloc_node mm/slub.c:3441 [inline]
__kmem_cache_alloc_node+0x136/0x320 mm/slub.c:3490
__do_kmalloc_node mm/slab_common.c:965 [inline]
__kmalloc+0x4e/0x190 mm/slab_common.c:979
kmalloc include/linux/slab.h:563 [inline]
sk_prot_alloc+0x140/0x290 net/core/sock.c:2077
sk_alloc+0x3a/0x7f0 net/core/sock.c:2130
__netlink_create+0x63/0x380 net/netlink/af_netlink.c:649
netlink_create+0x3b1/0x5f0 net/netlink/af_netlink.c:712
__sock_create+0x380/0x850 net/socket.c:1535
sock_create net/socket.c:1586 [inline]
__sys_socket_create net/socket.c:1623 [inline]
__sys_socket_create net/socket.c:1608 [inline]
__sys_socket+0x133/0x250 net/socket.c:1651
__do_sys_socket net/socket.c:1664 [inline]
__se_sys_socket net/socket.c:1662 [inline]
__x64_sys_socket+0x73/0xb0 net/socket.c:1662
page_owner free stack trace missing

Memory state around the buggy address:
ffff88802edbd380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802edbd400: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
>ffff88802edbd480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88802edbd500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802edbd580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[Herbert Xu]

On Mon, Jul 03, 2023 at 10:36:40PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: ae230642190a Merge branch 'af_unix-followup-fixes-for-so_p..
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11d7cc7f280000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c9bf1936936ca698
> dashboard link: https://syzkaller.appspot.com/bug?extid=e436ef6c393283630f64
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.

Adding David Howell to the cc.

Thanks,
--
Email: Herbert Xu <her...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[David Howells]

I'm pretty certain this is the same as:

https://syzkaller.appspot.com/bug?extid=689ec3afb1ef07b766b2

as I sometimes see the same trace when running the reproducer from there.
---

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

crypto: algif/hash: Fix race between MORE and non-MORE sends

The 'MSG_MORE' state of the previous sendmsg() is fetched without the
socket lock held, so two sendmsg calls can race. This can be seen with a
large sendfile() as that now does a series of sendmsg() calls, and if a
write() comes in on the same socket at an inopportune time, it can flip the
state.

Fix this by moving the fetch of ctx->more inside the socket lock.

Fixes: c662b043cdca ("crypto: af_alg/hash: Support MSG_SPLICE_PAGES")
Reported-by: syzbot+689ec3...@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/00000000000055...@google.com/
Signed-off-by: David Howells <dhow...@redhat.com>
cc: Herbert Xu <her...@gondor.apana.org.au>
cc: Paolo Abeni <pab...@redhat.com>
cc: "David S. Miller" <da...@davemloft.net>
cc: Eric Dumazet <edum...@google.com>
cc: Jakub Kicinski <ku...@kernel.org>
cc: linux-...@vger.kernel.org
cc: net...@vger.kernel.org

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 0ab43e149f0e..82c44d4899b9 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -68,13 +68,15 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
struct hash_ctx *ctx = ask->private;
ssize_t copied = 0;
size_t len, max_pages, npages;
- bool continuing = ctx->more, need_init = false;
+ bool continuing, need_init = false;
int err;

max_pages = min_t(size_t, ALG_MAX_PAGES,
DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE));

lock_sock(sk);
+ continuing = ctx->more;
+
if (!continuing) {
/* Discard a previous request that wasn't marked MSG_MORE. */
hash_free_result(sk, ctx);

[syzbot]

> I'm pretty certain this is the same as:
>
> https://syzkaller.appspot.com/bug?extid=689ec3afb1ef07b766b2
>
> as I sometimes see the same trace when running the reproducer from there.
> ---
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

This crash does not have a reproducer. I cannot test it.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.