[NET]: skb_trim audit

I found a few more spots where pskb_trim_rcsum could be used but were not.
This patch changes them to use it.

Also, sk_filter can get paged skb data.  Therefore we must use pskb_trim
instead of skb_trim.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 7 insertions, 22 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 75b0e97ed93d..96565ff0de6a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -873,10 +873,7 @@ static inline int sk_filter(struct sock *sk, struct sk_buff *skb, int needlock)
                 if (filter) {
                         unsigned int pkt_len = sk_run_filter(skb, filter->insns,
                                                              filter->len);
-                        if (!pkt_len)
-                                err = -EPERM;
-                        else
-                                skb_trim(skb, pkt_len);
+                        err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
                 }
 
                 if (needlock)
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 3da9264449f7..3e41f9d6d51c 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -407,12 +407,8 @@ static unsigned int br_nf_pre_routing_ipv6(unsigned int hook,
         if (pkt_len || hdr->nexthdr != NEXTHDR_HOP) {
                 if (pkt_len + sizeof(struct ipv6hdr) > skb->len)
                         goto inhdr_error;
-                if (pkt_len + sizeof(struct ipv6hdr) < skb->len) {
-                        if (__pskb_trim(skb, pkt_len + sizeof(struct ipv6hdr)))
-                                goto inhdr_error;
-                        if (skb->ip_summed == CHECKSUM_HW)
-                                skb->ip_summed = CHECKSUM_NONE;
-                }
+                if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
+                        goto inhdr_error;
         }
         if (hdr->nexthdr == NEXTHDR_HOP && check_hbh_len(skb))
                 goto inhdr_error;
@@ -495,11 +491,7 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
         if (skb->len < len || len < 4 * iph->ihl)
                 goto inhdr_error;
 
-        if (skb->len > len) {
-                __pskb_trim(skb, len);
-                if (skb->ip_summed == CHECKSUM_HW)
-                        skb->ip_summed = CHECKSUM_NONE;
-        }
+        pskb_trim_rcsum(skb, len);
 
         nf_bridge_put(skb->nf_bridge);
         if (!nf_bridge_alloc(skb))
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 3e319035f82d..c32a029e43f0 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -456,13 +456,9 @@ static int nf_ct_frag6_queue(struct nf_ct_frag6_queue *fq, struct sk_buff *skb,
                 DEBUGP("queue: message is too short.\n");
                 goto err;
         }
-        if (end-offset < skb->len) {
-                if (pskb_trim(skb, end - offset)) {
-                        DEBUGP("Can't trim\n");
-                        goto err;
-                }
-                if (skb->ip_summed != CHECKSUM_UNNECESSARY)
-                        skb->ip_summed = CHECKSUM_NONE;
+        if (pskb_trim_rcsum(skb, end - offset)) {
+                DEBUGP("Can't trim\n");
+                goto err;
         }
 
         /* Find out which fragments are in front and at the back of us