Commit 10df8e61 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

udp: fix IP_CHECKSUM handling 



First bug was added in commit ad6f939a ("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 ip_cmsg_recv(msg, skb) should have been replaced by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 e6afc8ac ("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: ad6f939a ("ip: Add offset parameter to ip_cmsg_recv")
Fixes: e6afc8ac ("udp: remove headers from UDP packets before queueing")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Sam Kumar <samanthakumar@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ecc515d7

include/net/ip.h

+2 −2
Original line number Diff line number Diff line
@@ -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);

net/ipv4/ip_sockglue.c

+6 −5
Original line number Diff line number Diff line
@@ -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;
@@ -106,7 +106,8 @@ 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),

		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);

net/ipv4/udp.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

net/ipv6/udp.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

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