Re: [PATCH rdma-rc] RDMA/nldev: Check stat attribute before accessing it

[Jason Gunthorpe]

On Wed, Nov 17, 2021 at 02:27:04PM +0200, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxx>
> 
> The access to non-existent netlink attribute causes to the following
> kernel panic. Fix it by checking existence before trying to read it.
> 
> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 6744 Comm: syz-executor.0 Not tainted 5.15.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:nla_get_u32 include/net/netlink.h:1554 [inline]
> RIP: 0010:nldev_stat_set_mode_doit drivers/infiniband/core/nldev.c:1909 [inline]
> RIP: 0010:nldev_stat_set_doit+0x578/0x10d0 drivers/infiniband/core/nldev.c:2040
> Code: fa 4c 8b a4 24 f8 02 00 00 48 b8 00 00 00 00 00 fc ff df c7 84 24 80 00 00 00 00 00 00 00 49 8d 7c 24 04 48 89
> fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 02
> RSP: 0018:ffffc90004acf2e8 EFLAGS: 00010247
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90002b94000
> RDX: 0000000000000000 RSI: ffffffff8684c5ff RDI: 0000000000000004
> RBP: ffff88807cda4000 R08: 0000000000000000 R09: ffff888023fb8027
> R10: ffffffff8684c5d7 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000001 R14: ffff888041024280 R15: ffff888031ade780
> FS:  00007eff9dddd700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b2ef24000 CR3: 0000000036902000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  rdma_nl_rcv_msg+0x36d/0x690 drivers/infiniband/core/netlink.c:195
>  rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
>  rdma_nl_rcv+0x2ee/0x430 drivers/infiniband/core/netlink.c:259
>  netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345
>  netlink_sendmsg+0x86d/0xda0 net/netlink/af_netlink.c:1916
>  sock_sendmsg_nosec net/socket.c:704 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:724
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7effa0867ae9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007eff9dddd188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00007effa097af60 RCX: 00007effa0867ae9
> RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003
> RBP: 00007effa08c1f6d R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffc008a753f R14: 00007eff9dddd300 R15: 0000000000022000
>  </TASK>
> Modules linked in:
> ---[ end trace bacb470dc6c820de ]---
> RIP: 0010:nla_get_u32 include/net/netlink.h:1554 [inline]
> RIP: 0010:nldev_stat_set_mode_doit drivers/infiniband/core/nldev.c:1909 [inline]
> RIP: 0010:nldev_stat_set_doit+0x578/0x10d0 drivers/infiniband/core/nldev.c:2040
> Code: fa 4c 8b a4 24 f8 02 00 00 48 b8 00 00 00 00 00 fc ff df c7 84 24 80 00 00 00 00 00 00 00 49 8d 7c 24 04 48 89
> fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 02
> RSP: 0018:ffffc90004acf2e8 EFLAGS: 00010247
> RIP: 0010:nldev_stat_set_mode_doit drivers/infiniband/core/nldev.c:1909 [inline]
> RIP: 0010:nldev_stat_set_doit+0x578/0x10d0 drivers/infiniband/core/nldev.c:2040
> Code: fa 4c 8b a4 24 f8 02 00 00 48 b8 00 00 00 00 00 fc ff df c7 84 24 80 00 00 00 00 00 00 00 49 8d 7c 24 04 48 89
> fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 02
> RSP: 0018:ffffc90004acf2e8 EFLAGS: 00010247
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90002b94000
> RDX: 0000000000000000 RSI: ffffffff8684c5ff RDI: 0000000000000004
> RBP: ffff88807cda4000 R08: 0000000000000000 R09: ffff888023fb8027
> R10: ffffffff8684c5d7 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000001 R14: ffff888041024280 R15: ffff888031ade780
> FS:  00007eff9dddd700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b2ef24000 CR3: 0000000036902000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> 
> Fixes: 822cf785ac6d ("RDMA/nldev: Split nldev_stat_set_mode_doit out of nldev_stat_set_doit")
> Reported-by: syzbot+9111d2255a9710e87562@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> ---
>  drivers/infiniband/core/nldev.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied to for-rc, thanks

Jason