BUG: unable to handle kernel paging request in dummy_set_vf_rss_query

BUG: unable to handle kernel paging request in dummy_set_vf_rss_query_en
Status: fixed on 2019/12/13 05:27
Reported-by: syzbot+278ff3551a1ad38e065e@syzkaller.appspotmail.com
Fix commit: 9ed49fc95f37 net: rtnetlink: prevent underflows in do_setvfinfo()
First crash: 1032d, last: 941d

Fix bisection: fixed by (bisect log) :
commit 9ed49fc95f37a457d940324c033c20d85cefb930
Author: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed Nov 20 12:34:38 2019 +0000

net: rtnetlink: prevent underflows in do_setvfinfo()

Sample crash report:

random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1563668704.928:36): avc:  denied  { map } for  pid=6942 comm="syz-executor865" path="/root/syz-executor865560153" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
BUG: unable to handle kernel paging request at fffffffbc96800d1
IP: dummy_set_vf_rss_query_en+0x7a/0xb0 /drivers/net/dummy.c:231
PGD 766d067 P4D 766d067 PUD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 6942 Comm: syz-executor865 Not tainted 4.14.133 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888081d8c380 task.stack: ffff888091960000
RIP: 0010:dummy_set_vf_rss_query_en+0x7a/0xb0 /drivers/net/dummy.c:231
RSP: 0018:ffff8880919672b0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: fffffffbc96800c0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 00000000d30f0008 RDI: fffffffbc96800d1
RBP: ffff8880919672c8 R08: 1ffff1101232ce99 R09: ffff8880919674c8
R10: ffffed101232cea5 R11: ffff88809196752f R12: ffff8880a1a3a600
R13: 0000000000000001 R14: ffff888091967610 R15: ffff8880909c85a8
FS:  0000000002050880(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffbc96800d1 CR3: 00000000884db000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_setvfinfo /net/core/rtnetlink.c:1878 [inline]
 do_setlink+0x19e9/0x2d50 /net/core/rtnetlink.c:2135
 rtnl_setlink+0x225/0x320 /net/core/rtnetlink.c:2303
 rtnetlink_rcv_msg+0x3eb/0xb70 /net/core/rtnetlink.c:4285
 netlink_rcv_skb+0x14f/0x3c0 /net/netlink/af_netlink.c:2432
 rtnetlink_rcv+0x1d/0x30 /net/core/rtnetlink.c:4297
 netlink_unicast_kernel /net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x45d/0x780 /net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 /net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec /net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 /net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 /net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 /net/socket.c:2096
 SYSC_sendmsg /net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 /net/socket.c:2103
 do_syscall_64+0x1e8/0x640 /arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4402e9
RSP: 002b:00007fff6d9dd958 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402e9
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401b70
R13: 0000000000401c00 R14: 0000000000000000 R15: 0000000000000000
Code: 48 8d 1c d0 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 11 48 89 fa 48 c1 ea 03 0f b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 16 <44> 88 6b 11 45 31 e4 e8 8a ac b8 fd 44 89 e0 5b 41 5c 41 5d 5d 
RIP: dummy_set_vf_rss_query_en+0x7a/0xb0 /drivers/net/dummy.c:231 RSP: ffff8880919672b0
CR2: fffffffbc96800d1
---[ end trace 12629820e7b7dd1b ]---

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci2-linux-4-14	2019/07/21 00:28	linux-4.14.y	aea8526edf59	1656845f	.config	log	report	syz	C
ci2-linux-4-14	2019/10/20 02:10	linux-4.14.y	b98aebd29824	8c88c9c1	.config	log	report
ci2-linux-4-14	2019/10/14 05:51	linux-4.14.y	e132c8d7b58d	2f661ec4	.config	log	report
ci2-linux-4-14	2019/08/15 09:11	linux-4.14.y	3ffe1e79c174	0d298d6b	.config	log	report
ci2-linux-4-14	2019/07/21 00:10	linux-4.14.y	aea8526edf59	1656845f	.config	log	report