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 <sd@xxxxxxxxxxxxxxx>
Reviewed-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
---
Note: this is based on 3.14.54, as 3.18 doesn't need the hunk for
net/rxrpc/ar-recvmsg.c, but all older stable kernels do.
include/linux/skbuff.h | 2 +-
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, 13 insertions(+), 7 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ab3133797ff7..220454f32509 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2431,7 +2431,7 @@ unsigned int datagram_poll(struct file *file, struct socket *sock,
int skb_copy_datagram_iovec(const struct sk_buff *from, int offset,
struct iovec *to, int size);
int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen,
- struct iovec *iov);
+ struct iovec *iov, int len);
int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset,
const struct iovec *from, int from_offset,
int len);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 13bc7dad7990..3437762668af 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -796,6 +796,7 @@ 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.
*
@@ -805,11 +806,14 @@ 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 9fbd69efa999..cf6168b897c3 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4934,7 +4934,7 @@ 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 6970e36ad7b8..8395cf5ec487 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1268,7 +1268,7 @@ 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 1f29996e368a..e6c9b4a7ee3c 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -492,7 +492,7 @@ 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 38625a91ec94..4011ccad6c9f 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -428,7 +428,8 @@ 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 4949f753686c..83484ebf691d 100644
--- a/net/rxrpc/ar-recvmsg.c
+++ b/net/rxrpc/ar-recvmsg.c
@@ -186,7 +186,8 @@ 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;
}
--
2.6.1
--
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