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authorEric Dumazet <edumazet@google.com>2018-03-26 08:08:07 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-13 19:50:24 +0200
commitae1ed37bae9cc34821a06c3920bb041e94e0fe2d (patch)
treed8282105c83936b777871ee53af9f6d12b8e9ba7 /net
parent451495e016614a116c7b8b26e940062acfcbde93 (diff)
net: fix possible out-of-bound read in skb_network_protocol()
[ Upstream commit 1dfe82ebd7d8fd43dba9948fdfb31f145014baa0 ] skb mac header is not necessarily set at the time skb_network_protocol() is called. Use skb->data instead. BUG: KASAN: slab-out-of-bounds in skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739 Read of size 2 at addr ffff8801b3097a0b by task syz-executor5/14242 CPU: 1 PID: 14242 Comm: syz-executor5 Not tainted 4.16.0-rc6+ #280 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443 skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739 harmonize_features net/core/dev.c:2924 [inline] netif_skb_features+0x509/0x9b0 net/core/dev.c:3011 validate_xmit_skb+0x81/0xb00 net/core/dev.c:3084 validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3142 packet_direct_xmit+0x117/0x790 net/packet/af_packet.c:256 packet_snd net/packet/af_packet.c:2944 [inline] packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2969 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2047 __sys_sendmsg+0xe5/0x210 net/socket.c:2081 Fixes: 19acc327258a ("gso: Handle Trans-Ether-Bridging protocol in skb_network_protocol()") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Pravin B Shelar <pshelar@ovn.org> Reported-by: Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index b2f589012c6b..ebf75524d252 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2515,7 +2515,7 @@ __be16 skb_network_protocol(struct sk_buff *skb, int *depth)
if (unlikely(!pskb_may_pull(skb, sizeof(struct ethhdr))))
return 0;
- eth = (struct ethhdr *)skb_mac_header(skb);
+ eth = (struct ethhdr *)skb->data;
type = eth->h_proto;
}