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netfilter: nfnetlink_log: fix maximum packet length logged to userspace 

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
9cefbbc9c8 (netfilter: nfnetlink_queue: cleanup copy_range usage).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2014-10-23 10:36:07 +02:00 committed by Pablo Neira Ayuso
parent 9dfa1dfe4d
commit c1e7dc91ee
1 changed files with 5 additions and 3 deletions
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8
net/netfilter/nfnetlink_log.c
View File

@ -43,7 +43,8 @@
#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);
@ -252,6 +253,8 @@ nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
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;
@ -679,8 +682,7 @@ 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;