From 127500d724f8c43f452610c9080444eedb5eaa6c Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Thu, 15 Oct 2015 14:25:03 +0200 Subject: [PATCH] net: add length argument to skb_copy_and_csum_datagram_iovec Without this length argument, we can read past the end of the iovec in memcpy_toiovec because we have no way of knowing the total length of the iovec's buffers. This is needed for stable kernels where 89c22d8c3b27 ("net: Fix skb csum races when peeking") has been backported but that don't have the ioviter conversion, which is almost all the stable trees <= 3.18. This also fixes a kernel crash for NFS servers when the client uses -onfsvers=3,proto=udp to mount the export. Signed-off-by: Sabrina Dubroca Reviewed-by: Hannes Frederic Sowa [bwh: Backported to 3.2: adjust context in include/linux/skbuff.h] Signed-off-by: Ben Hutchings --- include/linux/skbuff.h | 3 ++- net/core/datagram.c | 6 +++++- net/ipv4/tcp_input.c | 2 +- net/ipv4/udp.c | 2 +- net/ipv6/raw.c | 2 +- net/ipv6/udp.c | 3 ++- net/rxrpc/ar-recvmsg.c | 3 ++- 7 files changed, 14 insertions(+), 7 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1b4ea29d3943d..d38c2eebf1be8 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2131,7 +2131,8 @@ extern int skb_copy_datagram_iovec(const struct sk_buff *from, int size); extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen, - struct iovec *iov); + struct iovec *iov, + int len); extern int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, const struct iovec *from, diff --git a/net/core/datagram.c b/net/core/datagram.c index a4963138bf434..6616bfb33fa4a 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -709,6 +709,7 @@ EXPORT_SYMBOL(__skb_checksum_complete); * @skb: skbuff * @hlen: hardware length * @iov: io vector + * @len: amount of data to copy from skb to iov * * Caller _must_ check that skb will fit to this iovec. * @@ -718,11 +719,14 @@ EXPORT_SYMBOL(__skb_checksum_complete); * can be modified! */ int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, - int hlen, struct iovec *iov) + int hlen, struct iovec *iov, int len) { __wsum csum; int chunk = skb->len - hlen; + if (chunk > len) + chunk = len; + if (!chunk) return 0; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index afe688670f9ca..f8b58997c38e7 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5198,7 +5198,7 @@ static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen) err = skb_copy_datagram_iovec(skb, hlen, tp->ucopy.iov, chunk); else err = skb_copy_and_csum_datagram_iovec(skb, hlen, - tp->ucopy.iov); + tp->ucopy.iov, chunk); if (!err) { tp->ucopy.len -= chunk; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 5e920439a89ae..b1112217c76a6 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1207,7 +1207,7 @@ try_again: else { err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), - msg->msg_iov); + msg->msg_iov, copied); if (err == -EINVAL) goto csum_copy_err; diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 9287f3ea68324..240c102fda346 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -479,7 +479,7 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk, goto csum_copy_err; err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied); } else { - err = skb_copy_and_csum_datagram_iovec(skb, 0, msg->msg_iov); + err = skb_copy_and_csum_datagram_iovec(skb, 0, msg->msg_iov, copied); if (err == -EINVAL) goto csum_copy_err; } diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index dc08afd79bc5a..888892e441cea 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -383,7 +383,8 @@ try_again: err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov, copied ); else { - err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov); + err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), + msg->msg_iov, copied); if (err == -EINVAL) goto csum_copy_err; } diff --git a/net/rxrpc/ar-recvmsg.c b/net/rxrpc/ar-recvmsg.c index 5cc2da5d295d7..c67f5d3f6e619 100644 --- a/net/rxrpc/ar-recvmsg.c +++ b/net/rxrpc/ar-recvmsg.c @@ -185,7 +185,8 @@ int rxrpc_recvmsg(struct kiocb *iocb, struct socket *sock, msg->msg_iov, copy); } else { ret = skb_copy_and_csum_datagram_iovec(skb, offset, - msg->msg_iov); + msg->msg_iov, + copy); if (ret == -EINVAL) goto csum_copy_error; } -- 2.47.2