[PATCH 4/8] netfilter: nf_queue: reject NF_STOLEN verdicts from userspace
From: <hidden>
Date: 2011-08-30 14:41:17
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Florian Westphal <fw@strlen.de> A userspace listener may send (bogus) NF_STOLEN verdict, which causes skb leak. This problem was previously fixed via 64507fdbc29c3a622180378210ecea8659b14e40 (netfilter: nf_queue: fix NF_STOLEN skb leak) but this had to be reverted because NF_STOLEN can also be returned by a netfilter hook when iterating the rules in nf_reinject. Reject userspace NF_STOLEN verdict, as suggested by Michal Miroslaw. This is complementary to commit fad54440438a7c231a6ae347738423cbabc936d9 (netfilter: avoid double free in nf_reinject). Cc: Julian Anastasov <ja@ssi.bg> Cc: Eric Dumazet <redacted> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Patrick McHardy <redacted> --- net/ipv4/netfilter/ip_queue.c | 11 ++++------- net/ipv6/netfilter/ip6_queue.c | 11 ++++------- net/netfilter/nfnetlink_queue.c | 4 ++-- 3 files changed, 10 insertions(+), 16 deletions(-)
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 48f7d5b..e59aabd 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c@@ -314,7 +314,7 @@ ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len) { struct nf_queue_entry *entry; - if (vmsg->value > NF_MAX_VERDICT) + if (vmsg->value > NF_MAX_VERDICT || vmsg->value == NF_STOLEN) return -EINVAL; entry = ipq_find_dequeue_entry(vmsg->id);
@@ -359,12 +359,9 @@ ipq_receive_peer(struct ipq_peer_msg *pmsg, break; case IPQM_VERDICT: - if (pmsg->msg.verdict.value > NF_MAX_VERDICT) - status = -EINVAL; - else - status = ipq_set_verdict(&pmsg->msg.verdict, - len - sizeof(*pmsg)); - break; + status = ipq_set_verdict(&pmsg->msg.verdict, + len - sizeof(*pmsg)); + break; default: status = -EINVAL; }
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index 87b243a..e63c397 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c@@ -314,7 +314,7 @@ ipq_set_verdict(struct ipq_verdict_msg *vmsg, unsigned int len) { struct nf_queue_entry *entry; - if (vmsg->value > NF_MAX_VERDICT) + if (vmsg->value > NF_MAX_VERDICT || vmsg->value == NF_STOLEN) return -EINVAL; entry = ipq_find_dequeue_entry(vmsg->id);
@@ -359,12 +359,9 @@ ipq_receive_peer(struct ipq_peer_msg *pmsg, break; case IPQM_VERDICT: - if (pmsg->msg.verdict.value > NF_MAX_VERDICT) - status = -EINVAL; - else - status = ipq_set_verdict(&pmsg->msg.verdict, - len - sizeof(*pmsg)); - break; + status = ipq_set_verdict(&pmsg->msg.verdict, + len - sizeof(*pmsg)); + break; default: status = -EINVAL; }
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 00bd475..a80b0cb 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c@@ -646,8 +646,8 @@ verdicthdr_get(const struct nlattr * const nfqa[]) return NULL; vhdr = nla_data(nfqa[NFQA_VERDICT_HDR]); - verdict = ntohl(vhdr->verdict); - if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT) + verdict = ntohl(vhdr->verdict) & NF_VERDICT_MASK; + if (verdict > NF_MAX_VERDICT || verdict == NF_STOLEN) return NULL; return vhdr; }
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1.7.2.3