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

[Eric Dumazet]

On Mon, Apr 8, 2024 at 7:37 AM syzbot
<syzbot+ecd7e07b4be038658c9f@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> 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: syzbot+ecd7e07b4be038658c9f@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> ==================================================================
> 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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>
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Probably caused by

commit 948dbafc15da900b13c2bc9e244b9e109303907b
Author: Hangbin Liu <liuhangbin@xxxxxxxxx>
Date:   Mon Apr 1 11:10:03 2024 +0800

    net: team: use policy generated by YAML spec

    generated with:

     $ ./tools/net/ynl/ynl-gen-c.py --mode kernel \
     > --spec Documentation/netlink/specs/team.yaml --source \
     > -o drivers/net/team/team_nl.c
     $ ./tools/net/ynl/ynl-gen-c.py --mode kernel \
     > --spec Documentation/netlink/specs/team.yaml --header \
     > -o drivers/net/team/team_nl.h

    The TEAM_ATTR_LIST_PORT in team_nl_policy is removed as it is only in the
    port list reply attributes.

    Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
    Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240401031004.1159713-4-liuhangbin@xxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>