netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c
@ 2014-10-20  8:49 roy.qing.li
  2014-10-20  8:49 ` [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c roy.qing.li
  2014-10-22  1:42 ` [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c David Miller
  0 siblings, 2 replies; 4+ messages in thread
From: roy.qing.li @ 2014-10-20  8:49 UTC (permalink / raw)
  To: netdev; +Cc: steffen.klassert

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

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c
  2014-10-20  8:49 [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c roy.qing.li
@ 2014-10-20  8:49 ` 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
  1 sibling, 1 reply; 4+ messages in thread
From: roy.qing.li @ 2014-10-20  8:49 UTC (permalink / raw)
  To: netdev; +Cc: steffen.klassert

From: Li RongQing <roy.qing.li@gmail.com>

pskb_may_pull() maybe change skb->data and make nh and exthdr pointer
oboslete, so recompute the nd and exthdr

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
---
 net/ipv6/xfrm6_policy.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index ac49f84..115fd3b 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -170,8 +170,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 		case IPPROTO_DCCP:
 			if (!onlyproto && (nh + offset + 4 < skb->data ||
 			     pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
-				__be16 *ports = (__be16 *)exthdr;
+				__be16 *ports;
 
+				nh = skb_network_header(skb);
+				ports = (__be16*)(nh + offset);
 				fl6->fl6_sport = ports[!!reverse];
 				fl6->fl6_dport = ports[!reverse];
 			}
@@ -180,8 +182,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 
 		case IPPROTO_ICMPV6:
 			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
-				u8 *icmp = (u8 *)exthdr;
+				u8 *icmp;
 
+				nh = skb_network_header(skb);
+				icmp = (u8*)(nh + offset);
 				fl6->fl6_icmp_type = icmp[0];
 				fl6->fl6_icmp_code = icmp[1];
 			}
@@ -192,8 +196,9 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 		case IPPROTO_MH:
 			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 				struct ip6_mh *mh;
-				mh = (struct ip6_mh *)exthdr;
 
+				nh = skb_network_header(skb);
+				mh = (struct ip6_mh*)(nh + offset);
 				fl6->fl6_mh_type = mh->ip6mh_type;
 			}
 			fl6->flowi6_proto = nexthdr;
-- 
1.7.10.4

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c
  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
  0 siblings, 0 replies; 4+ messages in thread
From: Sergei Shtylyov @ 2014-10-20 10:36 UTC (permalink / raw)
  To: roy.qing.li, netdev; +Cc: steffen.klassert

Hello.

On 10/20/2014 12:49 PM, roy.qing.li@gmail.com wrote:

> From: Li RongQing <roy.qing.li@gmail.com>

> pskb_may_pull() maybe change skb->data and make nh and exthdr pointer
> oboslete, so recompute the nd and exthdr

> Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
> ---
>   net/ipv6/xfrm6_policy.c |   11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)

> diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
> index ac49f84..115fd3b 100644
> --- a/net/ipv6/xfrm6_policy.c
> +++ b/net/ipv6/xfrm6_policy.c
> @@ -170,8 +170,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
>   		case IPPROTO_DCCP:
>   			if (!onlyproto && (nh + offset + 4 < skb->data ||
>   			     pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
> -				__be16 *ports = (__be16 *)exthdr;
> +				__be16 *ports;
>
> +				nh = skb_network_header(skb);
> +				ports = (__be16*)(nh + offset);

    Please insert a space between '__be16' and * like it was done in the 
deleted assignment.

[...]
> @@ -180,8 +182,10 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
>
>   		case IPPROTO_ICMPV6:
>   			if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
> -				u8 *icmp = (u8 *)exthdr;
> +				u8 *icmp;
>
> +				nh = skb_network_header(skb);
> +				icmp = (u8*)(nh + offset);

    Likewise.

[...]
> @@ -192,8 +196,9 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
>   		case IPPROTO_MH:
>   			if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
>   				struct ip6_mh *mh;
> -				mh = (struct ip6_mh *)exthdr;
>
> +				nh = skb_network_header(skb);
> +				mh = (struct ip6_mh*)(nh + offset);

    Likewise.

[...]

WBR, Sergei

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c
  2014-10-20  8:49 [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c roy.qing.li
  2014-10-20  8:49 ` [PATCH 2/2] xfrm6: fix a potential use after free in xfrm6_policy.c roy.qing.li
@ 2014-10-22  1:42 ` David Miller
  1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2014-10-22  1:42 UTC (permalink / raw)
  To: roy.qing.li; +Cc: netdev, steffen.klassert

From: roy.qing.li@gmail.com
Date: Mon, 20 Oct 2014 16:49:13 +0800

> 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>

Please don't use macros that hide uses of local variables.

That is almost as bad as hiding control flow inside of
a macro.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2014-10-22  1:42 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-10-20  8:49 [PATCH 1/2] xfrm: fix a potential use after free in xfrm4_policy.c roy.qing.li
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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).