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xfrm4: Reload skb header pointers after calling pskb_may_pull.
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A call to pskb_may_pull may change the pointers into the packet,
so reload the pointers after the call.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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Steffen Klassert committed Oct 23, 2015
1 parent 1a14f1e commit ea673a4
Showing 1 changed file with 26 additions and 7 deletions.
33 changes: 26 additions & 7 deletions net/ipv4/xfrm4_policy.c
Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,10 @@ _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;

xprth = skb_network_header(skb) + iph->ihl * 4;
ports = (__be16 *)xprth;

fl4->fl4_sport = ports[!!reverse];
fl4->fl4_dport = ports[!reverse];
Expand All @@ -139,7 +142,10 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_ICMP:
if (xprth + 2 < skb->data ||
pskb_may_pull(skb, xprth + 2 - skb->data)) {
u8 *icmp = xprth;
u8 *icmp;

xprth = skb_network_header(skb) + iph->ihl * 4;
icmp = xprth;

fl4->fl4_icmp_type = icmp[0];
fl4->fl4_icmp_code = icmp[1];
Expand All @@ -149,7 +155,10 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_ESP:
if (xprth + 4 < skb->data ||
pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be32 *ehdr = (__be32 *)xprth;
__be32 *ehdr;

xprth = skb_network_header(skb) + iph->ihl * 4;
ehdr = (__be32 *)xprth;

fl4->fl4_ipsec_spi = ehdr[0];
}
Expand All @@ -158,7 +167,10 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_AH:
if (xprth + 8 < skb->data ||
pskb_may_pull(skb, xprth + 8 - skb->data)) {
__be32 *ah_hdr = (__be32 *)xprth;
__be32 *ah_hdr;

xprth = skb_network_header(skb) + iph->ihl * 4;
ah_hdr = (__be32 *)xprth;

fl4->fl4_ipsec_spi = ah_hdr[1];
}
Expand All @@ -167,7 +179,10 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_COMP:
if (xprth + 4 < skb->data ||
pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ipcomp_hdr = (__be16 *)xprth;
__be16 *ipcomp_hdr;

xprth = skb_network_header(skb) + iph->ihl * 4;
ipcomp_hdr = (__be16 *)xprth;

fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
}
Expand All @@ -176,8 +191,12 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
case IPPROTO_GRE:
if (xprth + 12 < skb->data ||
pskb_may_pull(skb, xprth + 12 - skb->data)) {
__be16 *greflags = (__be16 *)xprth;
__be32 *gre_hdr = (__be32 *)xprth;
__be16 *greflags;
__be32 *gre_hdr;

xprth = skb_network_header(skb) + iph->ihl * 4;
greflags = (__be16 *)xprth;
gre_hdr = (__be32 *)xprth;

if (greflags[0] & GRE_KEY) {
if (greflags[0] & GRE_CSUM)
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