path: root/net/ipv4/udp.c
diff options
authorWillem de Bruijn <willemb@google.com>2018-04-30 15:58:36 -0400
committerDavid S. Miller <davem@davemloft.net>2018-05-01 14:20:14 -0400
commita8c744a8b43733509b5625e65fee1985fbb901d7 (patch)
tree718ee5ccc5242b7d269cfe359858441a442337f1 /net/ipv4/udp.c
parentcls_flower: Support multiple masks per priority (diff)
udp: disable gso with no_check_tx
Syzbot managed to send a udp gso packet without checksum offload into the gso stack by disabling tx checksum (UDP_NO_CHECK6_TX). This triggered the skb_warn_bad_offload. RIP: 0010:skb_warn_bad_offload+0x2bc/0x600 net/core/dev.c:2658 skb_gso_segment include/linux/netdevice.h:4038 [inline] validate_xmit_skb+0x54d/0xd90 net/core/dev.c:3120 __dev_queue_xmit+0xbf8/0x34c0 net/core/dev.c:3577 dev_queue_xmit+0x17/0x20 net/core/dev.c:3618 UDP_NO_CHECK6_TX sets skb->ip_summed to CHECKSUM_NONE just after the udp gso integrity checks in udp_(v6_)send_skb. Extend those checks to catch and fail in this case. After the integrity checks jump directly to the CHECKSUM_PARTIAL case to avoid reading the no_check_tx flags again (a TOCTTOU race). Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp.c')
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 794aeafeb782..dd3102a37ef9 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -786,11 +786,14 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
return -EINVAL;
if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS)
return -EINVAL;
+ if (sk->sk_no_check_tx)
+ return -EINVAL;
if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite)
return -EIO;
skb_shinfo(skb)->gso_size = cork->gso_size;
skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
+ goto csum_partial;
if (is_udplite) /* UDP-Lite */
@@ -802,6 +805,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
goto send;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
goto send;