Subject: [syzbot] [net?] KASAN: global-out-of-bounds Read in __nla_validate_parse

From: syzbot <[email-masked]>
Date: Sun, 07 Apr 2024 22:37:33 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    8568bb2ccc27 Add linux-next specific files for 20240405
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16446339180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=48ca5acf8d2eb3bc
dashboard link: https://syzkaller.appspot.com/bug?extid=ecd7e07b4be038658c9f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=134f60bd180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1043b303180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d120b5e779c/disk-8568bb2c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a89e3589a585/vmlinux-8568bb2c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/045e657c0e0d/bzImage-8568bb2c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

==================================================================
BUG: KASAN: global-out-of-bounds in validate_nla lib/nlattr.c:411 [inline]
BUG: KASAN: global-out-of-bounds in __nla_validate_parse+0x1f1c/0x2f70 lib/nlattr.c:635
Read of size 1 at addr ffffffff8c55d030 by task syz-executor361/5080

CPU: 1 PID: 5080 Comm: syz-executor361 Not tainted 6.9.0-rc2-next-20240405-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 validate_nla lib/nlattr.c:411 [inline]
 __nla_validate_parse+0x1f1c/0x2f70 lib/nlattr.c:635
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 __nlmsg_parse include/net/netlink.h:760 [inline]
 genl_family_rcv_msg_attrs_parse+0x1d1/0x290 net/netlink/genetlink.c:945
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1093 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x802/0xec0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x72/0x7a
RIP: 0033:0x7f831a5c23a9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcd752ec88 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffcd752ee58 RCX: 00007f831a5c23a9
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00007f831a635610 R08: 00007f831a5fda23 R09: 00007ffcd752ee58
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffcd752ee48 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

The buggy address belongs to the variable:
 team_nl_policy+0x30/0x60

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xc55d
flags: 0xfff80000002000(reserved|node=0|zone=1|lastcpupid=0xfff)
raw: 00fff80000002000 ffffea0000315748 ffffea0000315748 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff8c55cf00: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00
 ffffffff8c55cf80: 00 00 00 00 f9 f9 f9 f9 00 00 00 00 f9 f9 f9 f9
>ffffffff8c55d000: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00
                                     ^
 ffffffff8c55d080: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 00 00 00 00
 ffffffff8c55d100: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 00 02 f9 f9
==================================================================

---
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