From: roy.qing.li@gmail.com
To: netdev@vger.kernel.org
Subject: [PATCH 1/2 v2] xfrm: fix a potential use after free in xfrm4_policy.c
Date: Wed, 22 Oct 2014 17:09:52 +0800 [thread overview]
Message-ID: <1413968993-13528-1-git-send-email-roy.qing.li@gmail.com> (raw)
From: Li RongQing <roy.qing.li@gmail.com>
pskb_may_pull() maybe change skb->data and make xprth pointer oboslete,
so recompute the xprth
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
---
Diff with v1: NEXT_HEAD add a length parameter, which hide on v1
net/ipv4/xfrm4_policy.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 6156f68..d7b33c5 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -98,11 +98,14 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
return 0;
}
+#define NEXT_HEAD(skb, length) (skb_network_header(skb) + length)
+
static void
_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
{
const struct iphdr *iph = ip_hdr(skb);
- u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
+ int ihl = iph->ihl * 4;
+ u8 *xprth = NEXT_HEAD(skb, ihl);
struct flowi4 *fl4 = &fl->u.ip4;
int oif = 0;
@@ -122,7 +125,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_DCCP:
if (xprth + 4 < skb->data ||
pskb_may_pull(skb, xprth + 4 - skb->data)) {
- __be16 *ports = (__be16 *)xprth;
+ __be16 *ports = (__be16 *)NEXT_HEAD(skb, ihl);
fl4->fl4_sport = ports[!!reverse];
fl4->fl4_dport = ports[!reverse];
@@ -131,7 +134,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_ICMP:
if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
- u8 *icmp = xprth;
+ u8 *icmp = NEXT_HEAD(skb, ihl);
fl4->fl4_icmp_type = icmp[0];
fl4->fl4_icmp_code = icmp[1];
@@ -140,7 +143,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_ESP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
- __be32 *ehdr = (__be32 *)xprth;
+ __be32 *ehdr = (__be32 *)NEXT_HEAD(skb, ihl);
fl4->fl4_ipsec_spi = ehdr[0];
}
@@ -148,7 +151,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_AH:
if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
- __be32 *ah_hdr = (__be32 *)xprth;
+ __be32 *ah_hdr = (__be32 *)NEXT_HEAD(skb, ihl);
fl4->fl4_ipsec_spi = ah_hdr[1];
}
@@ -156,17 +159,19 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_COMP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
- __be16 *ipcomp_hdr = (__be16 *)xprth;
+ __be16 *ipcomp_hdr;
+ ipcomp_hdr = (__be16 *)NEXT_HEAD(skb, ihl);
fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
}
break;
case IPPROTO_GRE:
if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
- __be16 *greflags = (__be16 *)xprth;
- __be32 *gre_hdr = (__be32 *)xprth;
+ __be16 *greflags;
+ __be32 *gre_hdr = (__be32 *)NEXT_HEAD(skb, ihl);
+ greflags = (__be16 *)NEXT_HEAD(skb, ihl);
if (greflags[0] & GRE_KEY) {
if (greflags[0] & GRE_CSUM)
gre_hdr++;
--
1.7.10.4
next reply other threads:[~2014-10-22 9:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-22 9:09 roy.qing.li [this message]
2014-10-22 9:09 ` [PATCH 2/2 v2] xfrm6: fix a potential use after free in xfrm6_policy.c roy.qing.li
2014-10-22 19:39 ` David Miller
2014-10-22 19:35 ` [PATCH 1/2 v2] xfrm: fix a potential use after free in xfrm4_policy.c David Miller
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