diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2007-09-16 16:22:13 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2007-09-16 16:22:13 -0700 |
| commit | 2a38b775b77f99308a4e571c13d908df78ac5e57 (patch) | |
| tree | 10f7bbe1d1a35c7383b7aa7fa865119a8bc0ae65 /drivers/net/ppp_generic.c | |
| parent | 7b797d5b150775d717cb03b5ada28b8bad99afab (diff) | |
| download | linux-2a38b775b77f99308a4e571c13d908df78ac5e57.tar.bz2 | |
[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>
Diffstat (limited to 'drivers/net/ppp_generic.c')
| -rw-r--r-- | drivers/net/ppp_generic.c | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c index 7e21342becb2..4b49d0e8c7eb 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 */ |