Commit b7047a1c authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: nfnetlink_log: fix EPERM when binding/unbinding and instance 0 exists 



When binding or unbinding to an address family, the res_id is usually set
to zero. When logging instance 0 already exists and is owned by a different
process, this makes nfunl_recv_config return -EPERM without performing
the bind operation.

Since no operation on the foreign logging instance itself was requested,
this is incorrect. Move bind/unbind commands before the queue instance
permissions checks.

Also remove an incorrect comment.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 019f692e

net/netfilter/nfnetlink_log.c

+16 −14
Original line number Diff line number Diff line
@@ -702,20 +702,30 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb, 
	struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);

	u_int16_t group_num = ntohs(nfmsg->res_id);

	struct nfulnl_instance *inst;

	struct nfulnl_msg_config_cmd *cmd = NULL;

	int ret = 0;



	if (nfula[NFULA_CFG_CMD]) {

		u_int8_t pf = nfmsg->nfgen_family;

		cmd = nla_data(nfula[NFULA_CFG_CMD]);



		/* Commands without queue context */

		switch (cmd->command) {

		case NFULNL_CFG_CMD_PF_BIND:

			return nf_log_register(pf, &nfulnl_logger);

		case NFULNL_CFG_CMD_PF_UNBIND:

			nf_log_unregister_pf(pf);

			return 0;

		}

	}



	inst = instance_lookup_get(group_num);

	if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {

		ret = -EPERM;

		goto out_put;

	}



	if (nfula[NFULA_CFG_CMD]) {

		u_int8_t pf = nfmsg->nfgen_family;

		struct nfulnl_msg_config_cmd *cmd;



		cmd = nla_data(nfula[NFULA_CFG_CMD]);



	if (cmd != NULL) {

		switch (cmd->command) {

		case NFULNL_CFG_CMD_BIND:

			if (inst) {
@@ -738,14 +748,6 @@ nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb, 


			instance_destroy(inst);

			goto out;

		case NFULNL_CFG_CMD_PF_BIND:

			ret = nf_log_register(pf, &nfulnl_logger);

			break;

		case NFULNL_CFG_CMD_PF_UNBIND:

			/* This is a bug and a feature.  We cannot unregister

			 * other handlers, like nfnetlink_inst can */

			nf_log_unregister_pf(pf);

			break;

		default:

			ret = -ENOTSUPP;

			break;

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