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authorHerbert Xu <herbert@gondor.apana.org.au>2007-09-16 16:22:13 -0700
committerDavid S. Miller <davem@davemloft.net>2007-09-16 16:22:13 -0700
commit2a38b775b77f99308a4e571c13d908df78ac5e57 (patch)
tree10f7bbe1d1a35c7383b7aa7fa865119a8bc0ae65
parent7b797d5b150775d717cb03b5ada28b8bad99afab (diff)
downloadlinux-linaro-2a38b775b77f99308a4e571c13d908df78ac5e57.tar.gz
[PPP] generic: Fix receive path data clobbering & non-linear handling
This patch adds missing pskb_may_pull calls to deal with non-linear packets that may arrive from pppoe or pppol2tp. It also copies cloned packets before writing over them. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ppp_generic.c44
1 files changed, 25 insertions, 19 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 7e21342becb..4b49d0e8c7e 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1525,7 +1525,7 @@ ppp_input_error(struct ppp_channel *chan, int code)
static void
ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
{
- if (skb->len >= 2) {
+ if (pskb_may_pull(skb, 2)) {
#ifdef CONFIG_PPP_MULTILINK
/* XXX do channel-level decompression here */
if (PPP_PROTO(skb) == PPP_MP)
@@ -1577,7 +1577,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP))
goto err;
- if (skb_tailroom(skb) < 124) {
+ if (skb_tailroom(skb) < 124 || skb_cloned(skb)) {
/* copy to a new sk_buff with more tailroom */
ns = dev_alloc_skb(skb->len + 128);
if (ns == 0) {
@@ -1648,23 +1648,29 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
/* check if the packet passes the pass and active filters */
/* the filter instructions are constructed assuming
a four-byte PPP header on each packet */
- *skb_push(skb, 2) = 0;
- if (ppp->pass_filter
- && sk_run_filter(skb, ppp->pass_filter,
- ppp->pass_len) == 0) {
- if (ppp->debug & 1)
- printk(KERN_DEBUG "PPP: inbound frame not passed\n");
- kfree_skb(skb);
- return;
- }
- if (!(ppp->active_filter
- && sk_run_filter(skb, ppp->active_filter,
- ppp->active_len) == 0))
- ppp->last_recv = jiffies;
- skb_pull(skb, 2);
-#else
- ppp->last_recv = jiffies;
+ if (ppp->pass_filter || ppp->active_filter) {
+ if (skb_cloned(skb) &&
+ pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ goto err;
+
+ *skb_push(skb, 2) = 0;
+ if (ppp->pass_filter
+ && sk_run_filter(skb, ppp->pass_filter,
+ ppp->pass_len) == 0) {
+ if (ppp->debug & 1)
+ printk(KERN_DEBUG "PPP: inbound frame "
+ "not passed\n");
+ kfree_skb(skb);
+ return;
+ }
+ if (!(ppp->active_filter
+ && sk_run_filter(skb, ppp->active_filter,
+ ppp->active_len) == 0))
+ ppp->last_recv = jiffies;
+ __skb_pull(skb, 2);
+ } else
#endif /* CONFIG_PPP_FILTER */
+ ppp->last_recv = jiffies;
if ((ppp->dev->flags & IFF_UP) == 0
|| ppp->npmode[npi] != NPMODE_PASS) {
@@ -1762,7 +1768,7 @@ ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
struct channel *ch;
int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
- if (!pskb_may_pull(skb, mphdrlen) || ppp->mrru == 0)
+ if (!pskb_may_pull(skb, mphdrlen + 1) || ppp->mrru == 0)
goto err; /* no good, throw it away */
/* Decode sequence number and begin/end bits */