[PATCH 3.16 086/254] ipv4: Use standard iovec primitive in raw_probe_proto_opt

Ben Hutchings
2018-02-28T16:10:03Z

From: Herbert Xu <herbert@gondor.apana.org.au>

commit 32b5913a931fd753faf3d4e1124b2bc2edb364da upstream.

The function raw_probe_proto_opt tries to extract the first two
bytes from the user input in order to seed the IPsec lookup for
ICMP packets. In doing so it's processing iovec by hand and
overcomplicating things.

This patch replaces the manual iovec processing with a call to
memcpy_fromiovecend.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/ipv4/raw.c | 50 +++++++++++---------------------------------------
1 file changed, 11 insertions(+), 39 deletions(-)

--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -417,48 +417,20 @@ error:

static int raw_probe_proto_opt(struct flowi4 *fl4, struct msghdr *msg)
{
- struct iovec *iov;
- u8 __user *type = NULL;
- u8 __user *code = NULL;
- int probed = 0;
- unsigned int i;
+ struct icmphdr icmph;
+ int err;

- if (!msg->msg_iov)
+ if (fl4->flowi4_proto != IPPROTO_ICMP)
return 0;

- for (i = 0; i < msg->msg_iovlen; i++) {
- iov = &msg->msg_iov[i];
- if (!iov)
- continue;
-
- switch (fl4->flowi4_proto) {
- case IPPROTO_ICMP:
- /* check if one-byte field is readable or not. */
- if (iov->iov_base && iov->iov_len < 1)
- break;
-
- if (!type) {
- type = iov->iov_base;
- /* check if code field is readable or not. */
- if (iov->iov_len > 1)
- code = type + 1;
- } else if (!code)
- code = iov->iov_base;
-
- if (type && code) {
- if (get_user(fl4->fl4_icmp_type, type) ||
- get_user(fl4->fl4_icmp_code, code))
- return -EFAULT;
- probed = 1;
- }
- break;
- default:
- probed = 1;
- break;
- }
- if (probed)
- break;
- }
+ /* We only need the first two bytes. */
+ err = memcpy_fromiovecend((void *)&icmph, msg->msg_iov, 0, 2);
+ if (err)
+ return err;
+
+ fl4->fl4_icmp_type = icmph.type;
+ fl4->fl4_icmp_code = icmph.code;
+
return 0;
}