[PATCH 3.10 44/70] netfilter: nfnetlink_log: fix maximum packet length logged to userspace

Greg Kroah-Hartman
2014-11-19T21:18:54Z

From: Florian Westphal <fw@strlen.de>

commit c1e7dc91eed0ed1a51c9b814d648db18bf8fc6e9 upstream.

don't try to queue payloads > 0xffff - NLA_HDRLEN, it does not work.
The nla length includes the size of the nla struct, so anything larger
results in u16 integer overflow.

This patch is similar to
9cefbbc9c8f9abe (netfilter: nfnetlink_queue: cleanup copy_range usage).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/netfilter/nfnetlink_log.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -45,7 +45,8 @@
#define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
#define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
#define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
-#define NFULNL_COPY_RANGE_MAX 0xFFFF /* max packet size is limited by 16-bit struct nfattr nfa_len field */
+/* max packet size is limited by 16-bit struct nfattr nfa_len field */
+#define NFULNL_COPY_RANGE_MAX (0xFFFF - NLA_HDRLEN)

#define PRINTR(x, args...) do { if (net_ratelimit()) \
printk(x, ## args); } while (0);
@@ -255,6 +256,8 @@ nfulnl_set_mode(struct nfulnl_instance *

case NFULNL_COPY_PACKET:
inst->copy_mode = mode;
+ if (range == 0)
+ range = NFULNL_COPY_RANGE_MAX;
inst->copy_range = min_t(unsigned int,
range, NFULNL_COPY_RANGE_MAX);
break;
@@ -677,8 +680,7 @@ nfulnl_log_packet(struct net *net,
break;

case NFULNL_COPY_PACKET:
- if (inst->copy_range == 0
- || inst->copy_range > skb->len)
+ if (inst->copy_range > skb->len)
data_len = skb->len;
else
data_len = inst->copy_range;