From: roy.qing.li@gmail.com
To: netdev@vger.kernel.org
Cc: steffen.klassert@secunet.com
Subject: [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c
Date: Mon, 20 Oct 2014 16:49:13 +0800 [thread overview]
Message-ID: <1413794954-16967-1-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>
---
net/ipv4/xfrm4_policy.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 6156f68..a4d8177 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) (skb_network_header(skb) + ihl)
+
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);
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);
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);
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);
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);
fl4->fl4_ipsec_spi = ah_hdr[1];
}
@@ -156,7 +159,7 @@ _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 = (__be16 *)NEXT_HEAD(skb);
fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
}
@@ -164,8 +167,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_GRE:
if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
- __be16 *greflags = (__be16 *)xprth;
- __be32 *gre_hdr = (__be32 *)xprth;
+ __be16 *greflags = (__be16 *)NEXT_HEAD(skb);
+ __be32 *gre_hdr = (__be32 *)NEXT_HEAD(skb);
if (greflags[0] & GRE_KEY) {
if (greflags[0] & GRE_CSUM)
--
1.7.10.4
next reply other threads:[~2014-10-20 8:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-20 8:49 roy.qing.li [this message]
2014-10-20 8:49 ` [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c roy.qing.li
2014-10-20 10:36 ` Sergei Shtylyov
2014-10-22 1:42 ` [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c David Miller
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