From: Steffen Klassert <steffen.klassert@secunet.com>
To: David Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Steffen Klassert <steffen.klassert@secunet.com>,
<netdev@vger.kernel.org>
Subject: [PATCH 3/5] xfrm4: Fix header checks in _decode_session4.
Date: Fri, 30 Oct 2015 07:16:28 +0100 [thread overview]
Message-ID: <1446185790-24214-4-git-send-email-steffen.klassert@secunet.com> (raw)
In-Reply-To: <1446185790-24214-1-git-send-email-steffen.klassert@secunet.com>
We skip the header informations if the data pointer points
already behind the header in question for some protocols.
This is because we call pskb_may_pull with a negative value
converted to unsigened int from pskb_may_pull in this case.
Skipping the header informations can lead to incorrect policy
lookups, so fix it by a check of the data pointer position
before we call pskb_may_pull.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/ipv4/xfrm4_policy.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 75e8d48..e4d533c 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -137,7 +137,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
case IPPROTO_ICMP:
- if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
+ if (xprth + 2 < skb->data ||
+ pskb_may_pull(skb, xprth + 2 - skb->data)) {
u8 *icmp = xprth;
fl4->fl4_icmp_type = icmp[0];
@@ -146,7 +147,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
case IPPROTO_ESP:
- if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
+ if (xprth + 4 < skb->data ||
+ pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be32 *ehdr = (__be32 *)xprth;
fl4->fl4_ipsec_spi = ehdr[0];
@@ -154,7 +156,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
case IPPROTO_AH:
- if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
+ if (xprth + 8 < skb->data ||
+ pskb_may_pull(skb, xprth + 8 - skb->data)) {
__be32 *ah_hdr = (__be32 *)xprth;
fl4->fl4_ipsec_spi = ah_hdr[1];
@@ -162,7 +165,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
case IPPROTO_COMP:
- if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
+ if (xprth + 4 < skb->data ||
+ pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ipcomp_hdr = (__be16 *)xprth;
fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
@@ -170,7 +174,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
case IPPROTO_GRE:
- if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
+ if (xprth + 12 < skb->data ||
+ pskb_may_pull(skb, xprth + 12 - skb->data)) {
__be16 *greflags = (__be16 *)xprth;
__be32 *gre_hdr = (__be32 *)xprth;
--
1.9.1
next prev parent reply other threads:[~2015-10-30 6:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 6:16 pull request (net-next): ipsec-next 2015-10-30 Steffen Klassert
2015-10-30 6:16 ` [PATCH 1/5] xfrm: Let the flowcache handle its size by default Steffen Klassert
2015-10-30 6:16 ` [PATCH 2/5] xfrm: Fix unaligned access to stats in copy_to_user_state() Steffen Klassert
2015-10-30 6:16 ` Steffen Klassert [this message]
2015-10-30 6:16 ` [PATCH 4/5] xfrm4: Reload skb header pointers after calling pskb_may_pull Steffen Klassert
2015-10-30 6:16 ` [PATCH 5/5] xfrm: Increment statistic counter on inner mode error Steffen Klassert
2015-10-30 11:53 ` pull request (net-next): ipsec-next 2015-10-30 David Miller
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