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authorSteffen Klassert <steffen.klassert@secunet.com>2019-02-26 07:04:50 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-25 18:23:41 +0200
commita654a73de29fe95b463fdbf792c681b67fb31780 (patch)
treea27109bed5939fb825e15ec1544706ed5c030542
parent6faa620606247d641201cf80c4521d252dc342c6 (diff)
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xfrm4: Fix uninitialized memory read in _decode_session4
[ Upstream commit 8742dc86d0c7a9628117a989c11f04a9b6b898f3 ] We currently don't reload pointers pointing into skb header after doing pskb_may_pull() in _decode_session4(). So in case pskb_may_pull() changed the pointers, we read from random memory. Fix this by putting all the needed infos on the stack, so that we don't need to access the header pointers after doing pskb_may_pull(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--net/ipv4/xfrm4_policy.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index d73a6d6652f6..2b144b92ae46 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -111,7 +111,8 @@ 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;
+ u8 *xprth = skb_network_header(skb) + ihl * 4;
struct flowi4 *fl4 = &fl->u.ip4;
int oif = 0;
@@ -122,6 +123,11 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
fl4->flowi4_mark = skb->mark;
fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
+ fl4->flowi4_proto = iph->protocol;
+ fl4->daddr = reverse ? iph->saddr : iph->daddr;
+ fl4->saddr = reverse ? iph->daddr : iph->saddr;
+ fl4->flowi4_tos = iph->tos;
+
if (!ip_is_fragment(iph)) {
switch (iph->protocol) {
case IPPROTO_UDP:
@@ -133,7 +139,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ports;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
ports = (__be16 *)xprth;
fl4->fl4_sport = ports[!!reverse];
@@ -146,7 +152,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
pskb_may_pull(skb, xprth + 2 - skb->data)) {
u8 *icmp;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
icmp = xprth;
fl4->fl4_icmp_type = icmp[0];
@@ -159,7 +165,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be32 *ehdr;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
ehdr = (__be32 *)xprth;
fl4->fl4_ipsec_spi = ehdr[0];
@@ -171,7 +177,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
pskb_may_pull(skb, xprth + 8 - skb->data)) {
__be32 *ah_hdr;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
ah_hdr = (__be32 *)xprth;
fl4->fl4_ipsec_spi = ah_hdr[1];
@@ -183,7 +189,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ipcomp_hdr;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
ipcomp_hdr = (__be16 *)xprth;
fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
@@ -196,7 +202,7 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
__be16 *greflags;
__be32 *gre_hdr;
- xprth = skb_network_header(skb) + iph->ihl * 4;
+ xprth = skb_network_header(skb) + ihl * 4;
greflags = (__be16 *)xprth;
gre_hdr = (__be32 *)xprth;
@@ -213,10 +219,6 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
break;
}
}
- fl4->flowi4_proto = iph->protocol;
- fl4->daddr = reverse ? iph->saddr : iph->daddr;
- fl4->saddr = reverse ? iph->daddr : iph->saddr;
- fl4->flowi4_tos = iph->tos;
}
static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,