[syzbot] KASAN: use-after-free Read in fw_load_sysfs_fallback

From: syzbot
Date: Fri Apr 02 2021 - 17:41:24 EST

Hello,

syzbot found the following issue on:

HEAD commit: 5ee96fa9 Merge tag 'irq-urgent-2021-03-21' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1028d621d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c51293a9ca630f6d
dashboard link: https://syzkaller.appspot.com/bug?extid=9b91d635e2b51efd6371
compiler: Debian clang version 11.0.1-2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1794dad6d00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f7afe6d00000

The issue was bisected to:

commit bcfbd3523f3c6eea51a74d217a8ebc5463bcb7f4
Author: Junyong Sun <sunjy516@xxxxxxxxx>
Date: Tue Mar 3 02:36:08 2020 +0000

firmware: fix a double abort case with fw_load_sysfs_fallback

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17e4778ad00000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1414778ad00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1014778ad00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9b91d635e2b51efd6371@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: bcfbd3523f3c ("firmware: fix a double abort case with fw_load_sysfs_fallback")

platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
==================================================================
BUG: KASAN: use-after-free in __list_add_valid+0x36/0xc0 lib/list_debug.c:23
Read of size 8 at addr ffff888014188ac8 by task syz-executor310/9819

CPU: 0 PID: 9819 Comm: syz-executor310 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x176/0x24e lib/dump_stack.c:120
print_address_description+0x5f/0x3a0 mm/kasan/report.c:232
__kasan_report mm/kasan/report.c:399 [inline]
kasan_report+0x15c/0x200 mm/kasan/report.c:416
__list_add_valid+0x36/0xc0 lib/list_debug.c:23
__list_add include/linux/list.h:67 [inline]
list_add include/linux/list.h:86 [inline]
fw_load_sysfs_fallback+0x110/0x720 drivers/base/firmware_loader/fallback.c:516
fw_load_from_user_helper+0x242/0x320 drivers/base/firmware_loader/fallback.c:581
_request_firmware+0x2c5/0x4c0 drivers/base/firmware_loader/main.c:831
request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:875
reg_reload_regdb+0x3a/0x1b0 net/wireless/reg.c:1095
genl_family_rcv_msg_doit net/netlink/genetlink.c:739 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
genl_rcv_msg+0xe4e/0x1280 net/netlink/genetlink.c:800
netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2502
genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg net/socket.c:674 [inline]
____sys_sendmsg+0x519/0x800 net/socket.c:2350
___sys_sendmsg net/socket.c:2404 [inline]
__sys_sendmsg+0x2bf/0x370 net/socket.c:2433
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x44ab59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 01 16 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:00007fa2b8ba9318 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004d62a8 RCX: 000000000044ab59
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000004d62a0 R08: 0000000000000099 R09: 0000000000000000
R10: 000000000000000c R11: 0000000000000246 R12: 0031313230386c6e
R13: 00007ffeeaba390f R14: 00007fa2b8ba9400 R15: 0000000000022000

Allocated by task 9818:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:427 [inline]
____kasan_kmalloc+0xc2/0xf0 mm/kasan/common.c:506
kasan_kmalloc include/linux/kasan.h:233 [inline]
kmem_cache_alloc_trace+0x21b/0x350 mm/slub.c:2934
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:684 [inline]
__allocate_fw_priv+0x98/0x340 drivers/base/firmware_loader/main.c:186
alloc_lookup_fw_priv+0x1c3/0x380 drivers/base/firmware_loader/main.c:250
_request_firmware_prepare+0x23c/0x5b0 drivers/base/firmware_loader/main.c:744
_request_firmware+0xd9/0x4c0 drivers/base/firmware_loader/main.c:806
request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:875
reg_reload_regdb+0x3a/0x1b0 net/wireless/reg.c:1095
genl_family_rcv_msg_doit net/netlink/genetlink.c:739 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
genl_rcv_msg+0xe4e/0x1280 net/netlink/genetlink.c:800
netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2502
genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg net/socket.c:674 [inline]
____sys_sendmsg+0x519/0x800 net/socket.c:2350
___sys_sendmsg net/socket.c:2404 [inline]
__sys_sendmsg+0x2bf/0x370 net/socket.c:2433
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 9815:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x3d/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:357
____kasan_slab_free+0x100/0x140 mm/kasan/common.c:360
kasan_slab_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:1562 [inline]
slab_free_freelist_hook+0x171/0x270 mm/slub.c:1600
slab_free mm/slub.c:3161 [inline]
kfree+0xcf/0x2d0 mm/slub.c:4213
kref_put include/linux/kref.h:65 [inline]
free_fw_priv drivers/base/firmware_loader/main.c:289 [inline]
firmware_free_data drivers/base/firmware_loader/main.c:584 [inline]
release_firmware+0x139/0x1b0 drivers/base/firmware_loader/main.c:1053
_request_firmware+0x3e1/0x4c0 drivers/base/firmware_loader/main.c:839
request_firmware+0x35/0x50 drivers/base/firmware_loader/main.c:875
reg_reload_regdb+0x3a/0x1b0 net/wireless/reg.c:1095
genl_family_rcv_msg_doit net/netlink/genetlink.c:739 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
genl_rcv_msg+0xe4e/0x1280 net/netlink/genetlink.c:800
netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2502
genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg net/socket.c:674 [inline]
____sys_sendmsg+0x519/0x800 net/socket.c:2350
___sys_sendmsg net/socket.c:2404 [inline]
__sys_sendmsg+0x2bf/0x370 net/socket.c:2433
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

Last potentially related work creation:
kasan_save_stack+0x27/0x50 mm/kasan/common.c:38
kasan_record_aux_stack+0xee/0x120 mm/kasan/generic.c:345
__call_rcu kernel/rcu/tree.c:3039 [inline]
call_rcu+0x130/0x8e0 kernel/rcu/tree.c:3114
fib6_info_release include/net/ip6_fib.h:337 [inline]
ip6_route_info_create+0xf84/0x17f0 net/ipv6/route.c:3736
ip6_route_add+0x22/0x120 net/ipv6/route.c:3746
addrconf_prefix_route net/ipv6/addrconf.c:2415 [inline]
inet6_addr_add+0x99e/0x11a0 net/ipv6/addrconf.c:2948
inet6_rtm_newaddr+0x754/0x2890 net/ipv6/addrconf.c:4869
rtnetlink_rcv_msg+0x895/0xd50 net/core/rtnetlink.c:5553
netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2502
netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1338
netlink_sendmsg+0x9ae/0xd50 net/netlink/af_netlink.c:1927
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg net/socket.c:674 [inline]
__sys_sendto+0x438/0x5c0 net/socket.c:1977
__do_sys_sendto net/socket.c:1989 [inline]
__se_sys_sendto net/socket.c:1985 [inline]
__x64_sys_sendto+0xda/0xf0 net/socket.c:1985
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888014188a00
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 200 bytes inside of
256-byte region [ffff888014188a00, ffff888014188b00)
The buggy address belongs to the page:
page:ffffea0000506200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14188
head:ffffea0000506200 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888010841b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888014188980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888014188a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888014188a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888014188b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888014188b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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