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udp: fix IP_CHECKSUM handling 

First bug was added in commit ad6f939ab1 ("ip: Add offset parameter to
ip_cmsg_recv") : Tom missed that ipv4 udp messages could be received on
AF_INET6 socket. ip_cmsg_recv(msg, skb) should have been replaced by
ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));

Then commit e6afc8ace6 ("udp: remove headers from UDP packets before
queueing") forgot to adjust the offsets now UDP headers are pulled
before skb are put in receive queue.

Fixes: ad6f939ab1 ("ip: Add offset parameter to ip_cmsg_recv")
Fixes: e6afc8ace6 ("udp: remove headers from UDP packets before queueing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sam Kumar <samanthakumar@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Eric Dumazet 2016-10-23 18:03:06 -07:00 committed by David S. Miller
parent ecc515d723
commit 10df8e6152
4 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/ip.h
View File

@ -578,7 +578,7 @@ int ip_options_rcv_srr(struct sk_buff *skb);
*/
void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int offset);
void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb, int tlen, int offset);
int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
struct ipcm_cookie *ipc, bool allow_ipv6);
int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
@ -600,7 +600,7 @@ void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
{
ip_cmsg_recv_offset(msg, skb, 0);
ip_cmsg_recv_offset(msg, skb, 0, 0);
}
bool icmp_global_allow(void);

11
net/ipv4/ip_sockglue.c
View File

@ -98,7 +98,7 @@ static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
}
static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
int offset)
int tlen, int offset)
{
__wsum csum = skb->csum;
@ -106,8 +106,9 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
return;
if (offset != 0)
csum = csum_sub(csum, csum_partial(skb_transport_header(skb),
offset, 0));
csum = csum_sub(csum,
csum_partial(skb_transport_header(skb) + tlen,
offset, 0));
put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
}
@ -153,7 +154,7 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
}
void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
int offset)
int tlen, int offset)
{
struct inet_sock *inet = inet_sk(skb->sk);
unsigned int flags = inet->cmsg_flags;
@ -216,7 +217,7 @@ void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
}
if (flags & IP_CMSG_CHECKSUM)
ip_cmsg_recv_checksum(msg, skb, offset);
ip_cmsg_recv_checksum(msg, skb, tlen, offset);
}
EXPORT_SYMBOL(ip_cmsg_recv_offset);

2
net/ipv4/udp.c
View File

@ -1322,7 +1322,7 @@ try_again:
*addr_len = sizeof(*sin);
}
if (inet->cmsg_flags)
ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr) + off);
ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr), off);
err = copied;
if (flags & MSG_TRUNC)

3
net/ipv6/udp.c
View File

@ -427,7 +427,8 @@ try_again:
if (is_udp4) {
if (inet->cmsg_flags)
ip_cmsg_recv(msg, skb);
ip_cmsg_recv_offset(msg, skb,
sizeof(struct udphdr), off);
} else {
if (np->rxopt.all)
ip6_datagram_recv_specific_ctl(sk, msg, skb);