[IPV4] raw: Strengthen check on validity of iph->ihl
We currently check that iph->ihl is bounded by the real length and that
the real length is greater than the minimum IP header length. However,
we did not check the caes where iph->ihl is less than the minimum IP
header length.
This breaks because some ip_fast_csum implementations assume that which
is quite reasonable.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 66b42f5..e7050f8 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -271,6 +271,7 @@
int hh_len;
struct iphdr *iph;
struct sk_buff *skb;
+ unsigned int iphlen;
int err;
if (length > rt->u.dst.dev->mtu) {
@@ -304,7 +305,8 @@
goto error_fault;
/* We don't modify invalid header */
- if (length >= sizeof(*iph) && iph->ihl * 4U <= length) {
+ iphlen = iph->ihl * 4;
+ if (iphlen >= sizeof(*iph) && iphlen <= length) {
if (!iph->saddr)
iph->saddr = rt->rt_src;
iph->check = 0;
