[ Upstream commit efcc9bcaf77c07df01371a7c34e50424c291f3ac ]
Fix a possible NULL pointer dereference in ip6erspan_set_version checking nlattr data pointer
kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 7549 Comm: syz-executor432 Not tainted 5.0.0-rc6-next-20190218 #37 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:ip6erspan_set_version+0x5c/0x350 net/ipv6/ip6_gre.c:1726 Code: 07 38 d0 7f 08 84 c0 0f 85 9f 02 00 00 49 8d bc 24 b0 00 00 00 c6 43 54 01 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 9a 02 00 00 4d 8b ac 24 b0 00 00 00 4d 85 ed 0f RSP: 0018:ffff888089ed7168 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8880869d6e58 RCX: 0000000000000000 RDX: 0000000000000016 RSI: ffffffff862736b4 RDI: 00000000000000b0 RBP: ffff888089ed7180 R08: 1ffff11010d3adcb R09: ffff8880869d6e58 R10: ffffed1010d3add5 R11: ffff8880869d6eaf R12: 0000000000000000 R13: ffffffff8931f8c0 R14: ffffffff862825d0 R15: ffff8880869d6e58 FS: 0000000000b3d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000184 CR3: 0000000092cc5000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip6erspan_newlink+0x66/0x7b0 net/ipv6/ip6_gre.c:2210 __rtnl_newlink+0x107b/0x16c0 net/core/rtnetlink.c:3176 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3234 rtnetlink_rcv_msg+0x465/0xb00 net/core/rtnetlink.c:5192 netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2485 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5210 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1925 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x806/0x930 net/socket.c:2136 __sys_sendmsg+0x105/0x1d0 net/socket.c:2174 __do_sys_sendmsg net/socket.c:2183 [inline] __se_sys_sendmsg net/socket.c:2181 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2181 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440159 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffa69156e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440159 RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000001 R09: 00000000004002c8 R10: 0000000000000011 R11: 0000000000000246 R12: 00000000004019e0 R13: 0000000000401a70 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace 09f8a7d13b4faaa1 ]--- RIP: 0010:ip6erspan_set_version+0x5c/0x350 net/ipv6/ip6_gre.c:1726 Code: 07 38 d0 7f 08 84 c0 0f 85 9f 02 00 00 49 8d bc 24 b0 00 00 00 c6 43 54 01 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 9a 02 00 00 4d 8b ac 24 b0 00 00 00 4d 85 ed 0f RSP: 0018:ffff888089ed7168 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8880869d6e58 RCX: 0000000000000000 RDX: 0000000000000016 RSI: ffffffff862736b4 RDI: 00000000000000b0 RBP: ffff888089ed7180 R08: 1ffff11010d3adcb R09: ffff8880869d6e58 R10: ffffed1010d3add5 R11: ffff8880869d6eaf R12: 0000000000000000 R13: ffffffff8931f8c0 R14: ffffffff862825d0 R15: ffff8880869d6e58 FS: 0000000000b3d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000184 CR3: 0000000092cc5000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: 4974d5f678ab ("net: ip6_gre: initialize erspan_ver just for erspan tunnels") Reported-and-tested-by: syzbot+30191cf1057abd3064af@syzkaller.appspotmail.com Signed-off-by: Lorenzo Bianconi lorenzo.bianconi@redhat.com Reviewed-by: Greg Rose gvrose8192@gmail.com Signed-off-by: David S. Miller davem@davemloft.net
Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv6/ip6_gre.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index c4a7db62658e..01ecd510014f 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1743,6 +1743,9 @@ static int ip6erspan_tap_validate(struct nlattr *tb[], struct nlattr *data[], static void ip6erspan_set_version(struct nlattr *data[], struct __ip6_tnl_parm *parms) { + if (!data) + return; + parms->erspan_ver = 1; if (data[IFLA_GRE_ERSPAN_VER]) parms->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);