diff options
| author | Willem de Bruijn <willemb@google.com> | 2018-04-30 15:58:36 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-05-01 14:20:14 -0400 |
| commit | a8c744a8b43733509b5625e65fee1985fbb901d7 (patch) | |
| tree | 718ee5ccc5242b7d269cfe359858441a442337f1 /net/ipv4/udp.c | |
| parent | 05cd271fd61a0bb64fc20c46c9c87b8272fb980c (diff) | |
| download | linux-a8c744a8b43733509b5625e65fee1985fbb901d7.tar.bz2 | |
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')
| -rw-r--r-- | net/ipv4/udp.c | 4 |
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 */ +csum_partial: udp4_hwcsum(skb, fl4->saddr, fl4->daddr); goto send; |