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authorEric Dumazet <edumazet@google.com>2013-04-12 11:07:47 -0700
committerDavid S. Miller <davem@davemloft.net>2013-04-12 15:25:41 -0400
commitd14a489a411937fb9420fe2b05168ee9e1e06c9c (patch)
tree1284608cf158d4b47a9aa877c8ee6a450fa502a0 /net/sched/act_csum.c
parent3619eb8541a6548f6e27b75aaa96cd53c4d9f3ef (diff)
downloadlinux-d14a489a411937fb9420fe2b05168ee9e1e06c9c.tar.bz2
act_csum: fix possible use after free
tcf_csum_skb_nextlayer() / pskb_may_pull() can change skb->head, so we must be careful not keeping pointers to previous headers. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Grégoire Baron <baronchon@n7mm.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/act_csum.c')
-rw-r--r--net/sched/act_csum.c39
1 files changed, 25 insertions, 14 deletions
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 08fa1e8a4ca4..3a4c0caa1f7d 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -166,15 +166,17 @@ static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
return 1;
}
-static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
unsigned int ihl, unsigned int ipl)
{
struct icmp6hdr *icmp6h;
+ const struct ipv6hdr *ip6h;
icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
if (icmp6h == NULL)
return 0;
+ ip6h = ipv6_hdr(skb);
icmp6h->icmp6_cksum = 0;
skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
@@ -186,15 +188,17 @@ static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
return 1;
}
-static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
+static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
unsigned int ihl, unsigned int ipl)
{
struct tcphdr *tcph;
+ const struct iphdr *iph;
tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
if (tcph == NULL)
return 0;
+ iph = ip_hdr(skb);
tcph->check = 0;
skb->csum = csum_partial(tcph, ipl - ihl, 0);
tcph->check = tcp_v4_check(ipl - ihl,
@@ -205,15 +209,17 @@ static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
return 1;
}
-static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
unsigned int ihl, unsigned int ipl)
{
struct tcphdr *tcph;
+ const struct ipv6hdr *ip6h;
tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
if (tcph == NULL)
return 0;
+ ip6h = ipv6_hdr(skb);
tcph->check = 0;
skb->csum = csum_partial(tcph, ipl - ihl, 0);
tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
@@ -225,10 +231,11 @@ static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
return 1;
}
-static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
+static int tcf_csum_ipv4_udp(struct sk_buff *skb,
unsigned int ihl, unsigned int ipl, int udplite)
{
struct udphdr *udph;
+ const struct iphdr *iph;
u16 ul;
/*
@@ -242,6 +249,7 @@ static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
if (udph == NULL)
return 0;
+ iph = ip_hdr(skb);
ul = ntohs(udph->len);
if (udplite || udph->check) {
@@ -276,10 +284,11 @@ ignore_obscure_skb:
return 1;
}
-static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+static int tcf_csum_ipv6_udp(struct sk_buff *skb,
unsigned int ihl, unsigned int ipl, int udplite)
{
struct udphdr *udph;
+ const struct ipv6hdr *ip6h;
u16 ul;
/*
@@ -293,6 +302,7 @@ static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
if (udph == NULL)
return 0;
+ ip6h = ipv6_hdr(skb);
ul = ntohs(udph->len);
udph->check = 0;
@@ -328,7 +338,7 @@ ignore_obscure_skb:
static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
{
- struct iphdr *iph;
+ const struct iphdr *iph;
int ntkoff;
ntkoff = skb_network_offset(skb);
@@ -353,19 +363,19 @@ static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
break;
case IPPROTO_TCP:
if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
- if (!tcf_csum_ipv4_tcp(skb, iph, iph->ihl * 4,
+ if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
ntohs(iph->tot_len)))
goto fail;
break;
case IPPROTO_UDP:
if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
- if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
+ if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
ntohs(iph->tot_len), 0))
goto fail;
break;
case IPPROTO_UDPLITE:
if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
- if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
+ if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
ntohs(iph->tot_len), 1))
goto fail;
break;
@@ -377,7 +387,7 @@ static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
goto fail;
- ip_send_check(iph);
+ ip_send_check(ip_hdr(skb));
}
return 1;
@@ -456,6 +466,7 @@ static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
ixhl = ipv6_optlen(ip6xh);
if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
goto fail;
+ ip6xh = (void *)(skb_network_header(skb) + hl);
if ((nexthdr == NEXTHDR_HOP) &&
!(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
goto fail;
@@ -464,25 +475,25 @@ static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
break;
case IPPROTO_ICMPV6:
if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
- if (!tcf_csum_ipv6_icmp(skb, ip6h,
+ if (!tcf_csum_ipv6_icmp(skb,
hl, pl + sizeof(*ip6h)))
goto fail;
goto done;
case IPPROTO_TCP:
if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
- if (!tcf_csum_ipv6_tcp(skb, ip6h,
+ if (!tcf_csum_ipv6_tcp(skb,
hl, pl + sizeof(*ip6h)))
goto fail;
goto done;
case IPPROTO_UDP:
if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
- if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
+ if (!tcf_csum_ipv6_udp(skb, hl,
pl + sizeof(*ip6h), 0))
goto fail;
goto done;
case IPPROTO_UDPLITE:
if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
- if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
+ if (!tcf_csum_ipv6_udp(skb, hl,
pl + sizeof(*ip6h), 1))
goto fail;
goto done;