Re: [syzbot] [crypto?] KASAN: slab-out-of-bounds Read in arc4_crypt

From: syzbot
Date: Wed Dec 20 2023 - 09:11:18 EST


Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-out-of-bounds Read in arc4_crypt

"syz-executor.0" (5486) uses obsolete ecb(arc4) skcipher
0, _skcipher_recvmsg
==================================================================
BUG: KASAN: slab-out-of-bounds in arc4_crypt+0x31c/0x4e0 lib/crypto/arc4.c:46
Read of size 4 at addr ffff8880221f66e0 by task syz-executor.0/5486

CPU: 0 PID: 5486 Comm: syz-executor.0 Not tainted 6.7.0-rc5-next-20231215-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
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
arc4_crypt+0x31c/0x4e0 lib/crypto/arc4.c:46
crypto_arc4_crypt+0x61/0x70 crypto/arc4.c:37
crypto_lskcipher_crypt_sg+0x28c/0x460 crypto/lskcipher.c:229
crypto_skcipher_decrypt+0xda/0x160 crypto/skcipher.c:692
_skcipher_recvmsg crypto/algif_skcipher.c:204 [inline]
skcipher_recvmsg+0xcd6/0x1100 crypto/algif_skcipher.c:226
sock_recvmsg_nosec net/socket.c:1044 [inline]
sock_recvmsg+0xe2/0x170 net/socket.c:1066
____sys_recvmsg+0x21f/0x5c0 net/socket.c:2801
___sys_recvmsg+0x115/0x1a0 net/socket.c:2843
__sys_recvmsg+0x114/0x1e0 net/socket.c:2873
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x62/0x6a
RIP: 0033:0x7fa471e7cba9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa472b000c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007fa471f9bf80 RCX: 00007fa471e7cba9
RDX: 0000000000000000 RSI: 00000000200005c0 RDI: 0000000000000004
RBP: 00007fa471ec847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa471f9bf80 R15: 00007ffec9ceddb8
</TASK>

Allocated by task 78:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
kasan_set_track+0x24/0x30 mm/kasan/common.c:61
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:590 [inline]
kzalloc include/linux/slab.h:711 [inline]
mpls_add_dev net/mpls/af_mpls.c:1461 [inline]
mpls_dev_notify+0x339/0xa00 net/mpls/af_mpls.c:1618
notifier_call_chain+0xb6/0x3d0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xbe/0x130 net/core/dev.c:1966
call_netdevice_notifiers_extack net/core/dev.c:2004 [inline]
call_netdevice_notifiers net/core/dev.c:2018 [inline]
register_netdevice+0x16e2/0x1da0 net/core/dev.c:10288
lowpan_newlink+0x30b/0x5c0 net/ieee802154/6lowpan/core.c:174
rtnl_newlink_create net/core/rtnetlink.c:3521 [inline]
__rtnl_newlink+0x118a/0x1940 net/core/rtnetlink.c:3741
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3754
rtnetlink_rcv_msg+0x3c7/0xe00 net/core/rtnetlink.c:6566
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2544
netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]
netlink_unicast+0x53b/0x810 net/netlink/af_netlink.c:1367
netlink_sendmsg+0x8b4/0xd70 net/netlink/af_netlink.c:1909
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0xd5/0x180 net/socket.c:745
__sys_sendto+0x225/0x310 net/socket.c:2189
__do_sys_sendto net/socket.c:2201 [inline]
__se_sys_sendto net/socket.c:2197 [inline]
__x64_sys_sendto+0xe0/0x1b0 net/socket.c:2197
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x62/0x6a

Last potentially related work creation:
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1540
prep_new_page mm/page_alloc.c:1547 [inline]
get_page_from_freelist+0xa19/0x3740 mm/page_alloc.c:3355
__alloc_pages+0x22e/0x2410 mm/page_alloc.c:4611
alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
alloc_slab_page mm/slub.c:2191 [inline]
allocate_slab mm/slub.c:2358 [inline]
new_slab+0x283/0x3c0 mm/slub.c:2411
___slab_alloc+0x4ab/0x1990 mm/slub.c:3544
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3629
__slab_alloc_node mm/slub.c:3682 [inline]
slab_alloc_node mm/slub.c:3854 [inline]
kmalloc_trace+0x2ff/0x330 mm/slub.c:4011
kmalloc include/linux/slab.h:590 [inline]
kzalloc include/linux/slab.h:711 [inline]
acpi_os_allocate_zeroed include/acpi/platform/aclinuxex.h:57 [inline]
acpi_ut_evaluate_object+0x80/0x490 drivers/acpi/acpica/uteval.c:50
acpi_ut_execute_CID+0x9a/0x780 drivers/acpi/acpica/utids.c:214
acpi_ns_get_device_callback+0x2ee/0x510 drivers/acpi/acpica/nsxfeval.c:694
acpi_ns_walk_namespace+0x3fe/0x5a0 drivers/acpi/acpica/nswalk.c:233
acpi_get_devices+0x135/0x160 drivers/acpi/acpica/nsxfeval.c:805
acpi_early_processor_control_setup+0x5a/0xb0 drivers/acpi/acpi_processor.c:601
acpi_bus_init drivers/acpi/bus.c:1366 [inline]
acpi_init+0x2c0/0xb70 drivers/acpi/bus.c:1430
do_one_initcall+0x128/0x680 init/main.c:1236

Second to last potentially related work creation:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:47
kasan_set_track+0x24/0x30 mm/kasan/common.c:61
__kasan_slab_alloc+0x81/0x90 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook mm/slub.c:3817 [inline]
slab_alloc_node mm/slub.c:3864 [inline]
kmem_cache_alloc+0x136/0x320 mm/slub.c:3871
kmem_cache_zalloc include/linux/slab.h:701 [inline]
acpi_os_acquire_object include/acpi/platform/aclinuxex.h:67 [inline]
acpi_ns_create_node+0x68/0x100 drivers/acpi/acpica/nsalloc.c:35
acpi_ns_search_and_enter+0x2ec/0x810 drivers/acpi/acpica/nssearch.c:373
acpi_ns_lookup+0x71e/0xce0 drivers/acpi/acpica/nsaccess.c:589
acpi_ds_create_buffer_field+0x2dc/0x610 drivers/acpi/acpica/dsfield.c:176
acpi_ds_load2_end_op+0x5d8/0x1070 drivers/acpi/acpica/dswload2.c:475
acpi_ds_exec_end_op+0xbb7/0x1460 drivers/acpi/acpica/dswexec.c:542
acpi_ps_parse_loop+0x429/0x1ce0 drivers/acpi/acpica/psloop.c:525
acpi_ps_parse_aml+0x3c1/0xca0 drivers/acpi/acpica/psparse.c:475
acpi_ps_execute_table+0x37b/0x4c0 drivers/acpi/acpica/psxface.c:295
acpi_ns_execute_table+0x3ee/0x550 drivers/acpi/acpica/nsparse.c:116
acpi_ns_load_table+0x5b/0x130 drivers/acpi/acpica/nsload.c:71
acpi_tb_load_namespace+0x435/0x700 drivers/acpi/acpica/tbxfload.c:186
acpi_load_tables+0x2c/0x110 drivers/acpi/acpica/tbxfload.c:59
acpi_bus_init drivers/acpi/bus.c:1321 [inline]
acpi_init+0x123/0xb70 drivers/acpi/bus.c:1430
do_one_initcall+0x128/0x680 init/main.c:1236
do_initcall_level init/main.c:1298 [inline]
do_initcalls init/main.c:1314 [inline]
do_basic_setup init/main.c:1333 [inline]
kernel_init_freeable+0x692/0xc30 init/main.c:1551
kernel_init+0x1c/0x2a0 init/main.c:1441
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

The buggy address belongs to the object at ffff8880221f6000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 1024 bytes to the right of
allocated 736-byte region [ffff8880221f6000, ffff8880221f62e0)

The buggy address belongs to the physical page:
page:ffffea0000887c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x221f0
head:ffffea0000887c00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888013041dc0 ffffea0000a19000 0000000000000003
raw: 0000000000000000 0000000080100010 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 0x1d2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 12, tgid 12 (kworker/u4:1), ts 88321977785, free_ts 88105026975
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1540
prep_new_page mm/page_alloc.c:1547 [inline]
get_page_from_freelist+0xa19/0x3740 mm/page_alloc.c:3355
__alloc_pages+0x22e/0x2410 mm/page_alloc.c:4611
alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
alloc_slab_page mm/slub.c:2191 [inline]
allocate_slab mm/slub.c:2358 [inline]
new_slab+0x283/0x3c0 mm/slub.c:2411
___slab_alloc+0x4ab/0x1990 mm/slub.c:3544
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3629
__slab_alloc_node mm/slub.c:3682 [inline]
slab_alloc_node mm/slub.c:3854 [inline]
__do_kmalloc_node mm/slub.c:3984 [inline]
__kmalloc_node_track_caller+0x367/0x470 mm/slub.c:4005
kmalloc_reserve+0xef/0x260 net/core/skbuff.c:582
__alloc_skb+0x12b/0x330 net/core/skbuff.c:651
alloc_skb include/linux/skbuff.h:1298 [inline]
nlmsg_new include/net/netlink.h:1010 [inline]
inet6_rt_notify+0xf0/0x2b0 net/ipv6/route.c:6171
fib6_del_route net/ipv6/ip6_fib.c:1999 [inline]
fib6_del+0xfae/0x17a0 net/ipv6/ip6_fib.c:2034
fib6_clean_node+0x41f/0x5b0 net/ipv6/ip6_fib.c:2196
fib6_walk_continue+0x44c/0x8c0 net/ipv6/ip6_fib.c:2118
fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2166
fib6_clean_tree+0xd7/0x110 net/ipv6/ip6_fib.c:2246
page last free pid 5144 tgid 5144 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+0x51f/0xb10 mm/page_alloc.c:2390
free_unref_page+0x33/0x3b0 mm/page_alloc.c:2530
__put_partials+0x14c/0x160 mm/slub.c:2926
qlink_free mm/kasan/quarantine.c:178 [inline]
qlist_free_all+0xc1/0x1e0 mm/kasan/quarantine.c:194
kasan_quarantine_reduce+0x18e/0x1d0 mm/kasan/quarantine.c:301
__kasan_slab_alloc+0x65/0x90 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook mm/slub.c:3817 [inline]
slab_alloc_node mm/slub.c:3864 [inline]
kmem_cache_alloc+0x136/0x320 mm/slub.c:3871
vm_area_alloc+0x1f/0x220 kernel/fork.c:463
do_brk_flags+0x2e1/0x1e30 mm/mmap.c:3166
__do_sys_brk+0x6ec/0xb40 mm/mmap.c:259
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x62/0x6a

Memory state around the buggy address:
ffff8880221f6580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880221f6600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880221f6680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8880221f6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880221f6780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit: 17cb8a20 Add linux-next specific files for 20231215
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12e6ec26e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ec104439b5dbc583
dashboard link: https://syzkaller.appspot.com/bug?extid=8ffb0839a24e9c6bfa76
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=14d429d6e80000