aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv6/route.c
diff options
context:
space:
mode:
authorIdo Schimmel <idosch@mellanox.com>2019-06-20 12:10:21 +0300
committerDavid S. Miller <davem@davemloft.net>2019-06-22 16:50:35 -0700
commit9eee3b4913d734b2c2496ddeea625d5b56583757 (patch)
treeb4eee41bc545c0bc3795cc48139680180fcc6dee /net/ipv6/route.c
parentfjes: no need to check return value of debugfs_create functions (diff)
downloadlinux-dev-9eee3b4913d734b2c2496ddeea625d5b56583757.tar.xz
linux-dev-9eee3b4913d734b2c2496ddeea625d5b56583757.zip
ipv6: Error when route does not have any valid nexthops
When user space sends invalid information in RTA_MULTIPATH, the nexthop list in ip6_route_multipath_add() is empty and 'rt_notif' is set to NULL. The code that emits the in-kernel notifications does not check for this condition, which results in a NULL pointer dereference [1]. Fix this by bailing earlier in the function if the parsed nexthop list is empty. This is consistent with the corresponding IPv4 code. v2: * Check if parsed nexthop list is empty and bail with extack set [1] 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: 0 PID: 9190 Comm: syz-executor149 Not tainted 5.2.0-rc5+ #38 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:call_fib6_multipath_entry_notifiers+0xd1/0x1a0 net/ipv6/ip6_fib.c:396 Code: 8b b5 30 ff ff ff 48 c7 85 68 ff ff ff 00 00 00 00 48 c7 85 70 ff ff ff 00 00 00 00 89 45 88 4c 89 e0 48 c1 e8 03 4c 89 65 80 <42> 80 3c 28 00 0f 85 9a 00 00 00 48 b8 00 00 00 00 00 fc ff df 4d RSP: 0018:ffff88809788f2c0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff11012f11e59 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88809788f390 R08: ffff88809788f8c0 R09: 000000000000000c R10: ffff88809788f5d8 R11: ffff88809788f527 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88809788f8c0 R15: ffffffff89541d80 FS: 000055555632c880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000080 CR3: 000000009ba7c000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip6_route_multipath_add+0xc55/0x1490 net/ipv6/route.c:5094 inet6_rtm_newroute+0xed/0x180 net/ipv6/route.c:5208 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5219 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5237 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 ___sys_sendmsg+0x803/0x920 net/socket.c:2286 __sys_sendmsg+0x105/0x1d0 net/socket.c:2324 __do_sys_sendmsg net/socket.c:2333 [inline] __se_sys_sendmsg net/socket.c:2331 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2331 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4401f9 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:00007ffc09fd0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401f9 RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a80 R13: 0000000000401b10 R14: 0000000000000000 R15: 0000000000000000 Reported-by: syzbot+382566d339d52cd1a204@syzkaller.appspotmail.com Fixes: ebee3cad835f ("ipv6: Add IPv6 multipath notifications for add / replace") Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/route.c')
-rw-r--r--net/ipv6/route.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index d72bcd8cffbd..4c5142a30808 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -5043,6 +5043,12 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
rtnh = rtnh_next(rtnh, &remaining);
}
+ if (list_empty(&rt6_nh_list)) {
+ NL_SET_ERR_MSG(extack,
+ "Invalid nexthop configuration - no valid nexthops");
+ return -EINVAL;
+ }
+
/* for add and replace send one notification with all nexthops.
* Skip the notification in fib6_add_rt2node and send one with
* the full route when done