| Message ID | 20190309224338.60907-1-edumazet@google.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] ip: fix ip_mc_may_pull() return value | expand |
From: Eric Dumazet <edumazet@google.com> Date: Sat, 9 Mar 2019 14:43:38 -0800 > ip_mc_may_pull() must return 0 if there is a problem, not an errno. > > syzbot reported : ... > Fixes: ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Cc: Linus Lüssing <linus.luessing@c0d3.blue> Applied, thanks Eric.
diff --git a/include/linux/igmp.h b/include/linux/igmp.h index cc85f4524dbfab28d03723c2fcb65c23730dee54..9c94b2ea789ceb9a06d9da0d8b07d28801732930 100644 --- a/include/linux/igmp.h +++ b/include/linux/igmp.h @@ -110,7 +110,7 @@ struct ip_mc_list { static inline int ip_mc_may_pull(struct sk_buff *skb, unsigned int len) { if (skb_transport_offset(skb) + ip_transport_len(skb) < len) - return -EINVAL; + return 0; return pskb_may_pull(skb, len); }
ip_mc_may_pull() must return 0 if there is a problem, not an errno. syzbot reported : BUG: KASAN: use-after-free in br_ip4_multicast_igmp3_report net/bridge/br_multicast.c:947 [inline] BUG: KASAN: use-after-free in br_multicast_ipv4_rcv net/bridge/br_multicast.c:1631 [inline] BUG: KASAN: use-after-free in br_multicast_rcv+0x3cd8/0x4440 net/bridge/br_multicast.c:1741 Read of size 4 at addr ffff88820a4084ee by task syz-executor.2/11183 CPU: 1 PID: 11183 Comm: syz-executor.2 Not tainted 5.0.0+ #14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 br_ip4_multicast_igmp3_report net/bridge/br_multicast.c:947 [inline] br_multicast_ipv4_rcv net/bridge/br_multicast.c:1631 [inline] br_multicast_rcv+0x3cd8/0x4440 net/bridge/br_multicast.c:1741 br_handle_frame_finish+0xa3a/0x14c0 net/bridge/br_input.c:108 br_nf_hook_thresh+0x2ec/0x380 net/bridge/br_netfilter_hooks.c:1005 br_nf_pre_routing_finish+0x8e2/0x1750 net/bridge/br_netfilter_hooks.c:410 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] br_nf_pre_routing+0x7e7/0x13a0 net/bridge/br_netfilter_hooks.c:506 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline] nf_hook_slow+0xbf/0x1f0 net/netfilter/core.c:511 nf_hook include/linux/netfilter.h:244 [inline] NF_HOOK include/linux/netfilter.h:287 [inline] br_handle_frame+0x95b/0x1450 net/bridge/br_input.c:305 __netif_receive_skb_core+0xa96/0x3040 net/core/dev.c:4902 __netif_receive_skb_one_core+0xa8/0x1a0 net/core/dev.c:4971 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5083 netif_receive_skb_internal+0x117/0x660 net/core/dev.c:5186 netif_receive_skb+0x6e/0x5a0 net/core/dev.c:5261 Fixes: ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Linus Lüssing <linus.luessing@c0d3.blue> --- include/linux/igmp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)