From: Patrick McHardy Date: Wed, 20 Feb 2008 01:17:52 +0000 (-0800) Subject: [NETFILTER]: {ip,ip6,nfnetlink}_queue: fix SKB_LINEAR_ASSERT when mangling packet... X-Git-Tag: v2.6.25-rc3~9^2~32 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e2b58a67;p=linux-2.6 [NETFILTER]: {ip,ip6,nfnetlink}_queue: fix SKB_LINEAR_ASSERT when mangling packet data As reported by Tomas Simonaitis , inserting new data in skbs queued over {ip,ip6,nfnetlink}_queue triggers a SKB_LINEAR_ASSERT in skb_put(). Going back through the git history, it seems this bug is present since at least 2.6.12-rc2, probably even since the removal of skb_linearize() for netfilter. Linearize non-linear skbs through skb_copy_expand() when enlarging them. Tested by Thomas, fixes bugzilla #9933. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index 6bda110285..fe05da41d6 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -283,8 +283,8 @@ static int ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct nf_queue_entry *e) { int diff; - int err; struct iphdr *user_iph = (struct iphdr *)v->payload; + struct sk_buff *nskb; if (v->data_len < sizeof(*user_iph)) return 0; @@ -296,14 +296,16 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct nf_queue_entry *e) if (v->data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - err = pskb_expand_head(e->skb, 0, + nskb = skb_copy_expand(e->skb, 0, diff - skb_tailroom(e->skb), GFP_ATOMIC); - if (err) { + if (!nskb) { printk(KERN_WARNING "ip_queue: error " - "in mangle, dropping packet: %d\n", -err); - return err; + "in mangle, dropping packet\n"); + return -ENOMEM; } + kfree_skb(e->skb); + e->skb = nskb; } skb_put(e->skb, diff); } diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index e869916b05..cc2f9afcf8 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -285,8 +285,8 @@ static int ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e) { int diff; - int err; struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload; + struct sk_buff *nskb; if (v->data_len < sizeof(*user_iph)) return 0; @@ -298,14 +298,16 @@ ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e) if (v->data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - err = pskb_expand_head(e->skb, 0, + nskb = skb_copy_expand(e->skb, 0, diff - skb_tailroom(e->skb), GFP_ATOMIC); - if (err) { + if (!nskb) { printk(KERN_WARNING "ip6_queue: OOM " "in mangle, dropping packet\n"); - return err; + return -ENOMEM; } + kfree_skb(e->skb); + e->skb = nskb; } skb_put(e->skb, diff); } diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index a48b20fe9c..0043d3a9f8 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -443,8 +443,8 @@ err_out: static int nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e) { + struct sk_buff *nskb; int diff; - int err; diff = data_len - e->skb->len; if (diff < 0) { @@ -454,14 +454,16 @@ nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e) if (data_len > 0xFFFF) return -EINVAL; if (diff > skb_tailroom(e->skb)) { - err = pskb_expand_head(e->skb, 0, + nskb = skb_copy_expand(e->skb, 0, diff - skb_tailroom(e->skb), GFP_ATOMIC); - if (err) { + if (!nskb) { printk(KERN_WARNING "nf_queue: OOM " "in mangle, dropping packet\n"); - return err; + return -ENOMEM; } + kfree_skb(e->skb); + e->skb = nskb; } skb_put(e->skb, diff); }