Commit 7643507f authored by Vishwanath Pai's avatar Vishwanath Pai Committed by Pablo Neira Ayuso
Browse files

netfilter: xt_NFLOG: nflog-range does not truncate packets 



li->u.ulog.copy_len is currently ignored by the kernel, we should truncate
the packet to either li->u.ulog.copy_len (if set) or copy_range before
sending it to userspace. 0 is a valid input for copy_len, so add a new
flag to indicate whether this was option was specified by the user or not.

Add two flags to indicate whether nflog-size/copy_len was set or not.
XT_NFLOG_F_COPY_LEN is for XT_NFLOG and NFLOG_F_COPY_LEN for nfnetlink_log

On the userspace side, this was initially represented by the option
nflog-range, this will be replaced by --nflog-size now. --nflog-range would
still exist but does not do anything.

Reported-by: default avatarJoe Dollard <jdollard@akamai.com>
Reviewed-by: default avatarJosh Hunt <johunt@akamai.com>
Signed-off-by: default avatarVishwanath Pai <vpai@akamai.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent e1dbbc59

include/net/netfilter/nf_log.h

+7 −0
Original line number Diff line number Diff line
@@ -12,6 +12,9 @@ 
#define NF_LOG_UID		0x08	/* Log UID owning local socket */

#define NF_LOG_MASK		0x0f



/* This flag indicates that copy_len field in nf_loginfo is set */

#define NF_LOG_F_COPY_LEN	0x1



enum nf_log_type {

	NF_LOG_TYPE_LOG		= 0,

	NF_LOG_TYPE_ULOG,
@@ -22,9 +25,13 @@ struct nf_loginfo { 
	u_int8_t type;

	union {

		struct {

			/* copy_len will be used iff you set

			 * NF_LOG_F_COPY_LEN in flags

			 */

			u_int32_t copy_len;

			u_int16_t group;

			u_int16_t qthreshold;

			u_int16_t flags;

		} ulog;

		struct {

			u_int8_t level;

include/uapi/linux/netfilter/xt_NFLOG.h

+5 −1
Original line number Diff line number Diff line
@@ -6,9 +6,13 @@ 
#define XT_NFLOG_DEFAULT_GROUP		0x1

#define XT_NFLOG_DEFAULT_THRESHOLD	0



#define XT_NFLOG_MASK			0x0

#define XT_NFLOG_MASK			0x1



/* This flag indicates that 'len' field in xt_nflog_info is set*/

#define XT_NFLOG_F_COPY_LEN		0x1



struct xt_nflog_info {

	/* 'len' will be used iff you set XT_NFLOG_F_COPY_LEN in flags */

	__u32	len;

	__u16	group;

	__u16	threshold;

net/netfilter/nfnetlink_log.c

+6 −3
Original line number Diff line number Diff line
@@ -700,10 +700,13 @@ nfulnl_log_packet(struct net *net, 
		break;



	case NFULNL_COPY_PACKET:

		if (inst->copy_range > skb->len)

			data_len = skb->len;

		else

		data_len = inst->copy_range;

		if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&

		    (li->u.ulog.copy_len < data_len))

			data_len = li->u.ulog.copy_len;



		if (data_len > skb->len)

			data_len = skb->len;



		size += nla_total_size(data_len);

		break;

net/netfilter/xt_NFLOG.c

+3 −0
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ nflog_tg(struct sk_buff *skb, const struct xt_action_param *par) 
	li.u.ulog.group	     = info->group;

	li.u.ulog.qthreshold = info->threshold;



	if (info->flags & XT_NFLOG_F_COPY_LEN)

		li.u.ulog.flags |= NF_LOG_F_COPY_LEN;



	nfulnl_log_packet(net, par->family, par->hooknum, skb, par->in,

			  par->out, &li, info->prefix);

	return XT_CONTINUE;

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