[NETFILTER]: {ip,ip6,nfnetlink}_queue: fix SKB_LINEAR_ASSERT when mangling packet data
As reported by Tomas Simonaitis <tomas.simonaitis@gmail.com>, 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 <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -283,8 +283,8 @@ static int
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ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
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{
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int diff;
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int err;
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struct iphdr *user_iph = (struct iphdr *)v->payload;
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struct sk_buff *nskb;
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if (v->data_len < sizeof(*user_iph))
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return 0;
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@ -296,14 +296,16 @@ ipq_mangle_ipv4(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
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if (v->data_len > 0xFFFF)
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return -EINVAL;
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if (diff > skb_tailroom(e->skb)) {
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err = pskb_expand_head(e->skb, 0,
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nskb = skb_copy_expand(e->skb, 0,
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diff - skb_tailroom(e->skb),
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GFP_ATOMIC);
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if (err) {
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if (!nskb) {
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printk(KERN_WARNING "ip_queue: error "
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"in mangle, dropping packet: %d\n", -err);
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return err;
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"in mangle, dropping packet\n");
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return -ENOMEM;
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}
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kfree_skb(e->skb);
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e->skb = nskb;
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}
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skb_put(e->skb, diff);
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}
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@ -285,8 +285,8 @@ static int
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ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
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{
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int diff;
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int err;
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struct ipv6hdr *user_iph = (struct ipv6hdr *)v->payload;
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struct sk_buff *nskb;
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if (v->data_len < sizeof(*user_iph))
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return 0;
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@ -298,14 +298,16 @@ ipq_mangle_ipv6(ipq_verdict_msg_t *v, struct nf_queue_entry *e)
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if (v->data_len > 0xFFFF)
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return -EINVAL;
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if (diff > skb_tailroom(e->skb)) {
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err = pskb_expand_head(e->skb, 0,
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nskb = skb_copy_expand(e->skb, 0,
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diff - skb_tailroom(e->skb),
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GFP_ATOMIC);
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if (err) {
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if (!nskb) {
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printk(KERN_WARNING "ip6_queue: OOM "
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"in mangle, dropping packet\n");
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return err;
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return -ENOMEM;
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}
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kfree_skb(e->skb);
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e->skb = nskb;
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}
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skb_put(e->skb, diff);
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}
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@ -443,8 +443,8 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
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static int
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nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e)
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{
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struct sk_buff *nskb;
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int diff;
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int err;
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diff = data_len - e->skb->len;
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if (diff < 0) {
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@ -454,14 +454,16 @@ nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e)
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if (data_len > 0xFFFF)
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return -EINVAL;
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if (diff > skb_tailroom(e->skb)) {
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err = pskb_expand_head(e->skb, 0,
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nskb = skb_copy_expand(e->skb, 0,
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diff - skb_tailroom(e->skb),
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GFP_ATOMIC);
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if (err) {
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if (!nskb) {
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printk(KERN_WARNING "nf_queue: OOM "
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"in mangle, dropping packet\n");
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return err;
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return -ENOMEM;
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}
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kfree_skb(e->skb);
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e->skb = nskb;
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}
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skb_put(e->skb, diff);
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}
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