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Commit a52e95ab authored by Lorenzo Colitti's avatar Lorenzo Colitti Committed by David S. Miller
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net: diag: allow socket bytecode filters to match socket marks 

This allows a privileged process to filter by socket mark when
dumping sockets via INET_DIAG_BY_FAMILY. This is useful on
systems that use mark-based routing such as Android.

The ability to filter socket marks requires CAP_NET_ADMIN, which
is consistent with other privileged operations allowed by the
SOCK_DIAG interface such as the ability to destroy sockets and
the ability to inspect BPF filters attached to packet sockets.

Tested: https://android-review.googlesource.com/261350


Signed-off-by: default avatarLorenzo Colitti <lorenzo@google.com>
Acked-by: default avatarDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 627cc4ad

include/uapi/linux/inet_diag.h

+6 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ enum { 
	INET_DIAG_BC_S_COND,

	INET_DIAG_BC_D_COND,

	INET_DIAG_BC_DEV_COND,   /* u32 ifindex */

	INET_DIAG_BC_MARK_COND,

};



struct inet_diag_hostcond {
@@ -82,6 +83,11 @@ struct inet_diag_hostcond { 
	__be32	addr[0];

};



struct inet_diag_markcond {

	__u32 mark;

	__u32 mask;

};



/* Base info structure. It contains socket identity (addrs/ports/cookie)

 * and, alas, the information shown by netstat. */

struct inet_diag_msg {

net/ipv4/inet_diag.c

+33 −3
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ struct inet_diag_entry { 
	u16 family;

	u16 userlocks;

	u32 ifindex;

	u32 mark;

};



static DEFINE_MUTEX(inet_diag_table_mutex);
@@ -580,6 +581,14 @@ static int inet_diag_bc_run(const struct nlattr *_bc, 
				yes = 0;

			break;

		}

		case INET_DIAG_BC_MARK_COND: {

			struct inet_diag_markcond *cond;



			cond = (struct inet_diag_markcond *)(op + 1);

			if ((entry->mark & cond->mask) != cond->mark)

				yes = 0;

			break;

		}

		}



		if (yes) {
@@ -624,6 +633,12 @@ int inet_diag_bc_sk(const struct nlattr *bc, struct sock *sk) 
	entry.dport = ntohs(inet->inet_dport);

	entry.ifindex = sk->sk_bound_dev_if;

	entry.userlocks = sk_fullsock(sk) ? sk->sk_userlocks : 0;

	if (sk_fullsock(sk))

		entry.mark = sk->sk_mark;

	else if (sk->sk_state == TCP_NEW_SYN_RECV)

		entry.mark = inet_rsk(inet_reqsk(sk))->ir_mark;

	else

		entry.mark = 0;



	return inet_diag_bc_run(bc, &entry);

}
@@ -706,8 +721,17 @@ static bool valid_port_comparison(const struct inet_diag_bc_op *op, 
	return true;

}



static int inet_diag_bc_audit(const struct nlattr *attr)

static bool valid_markcond(const struct inet_diag_bc_op *op, int len,

			   int *min_len)

{

	*min_len += sizeof(struct inet_diag_markcond);

	return len >= *min_len;

}



static int inet_diag_bc_audit(const struct nlattr *attr,

			      const struct sk_buff *skb)

{

	bool net_admin = netlink_net_capable(skb, CAP_NET_ADMIN);

	const void *bytecode, *bc;

	int bytecode_len, len;
@@ -738,6 +762,12 @@ static int inet_diag_bc_audit(const struct nlattr *attr) 
			if (!valid_port_comparison(bc, len, &min_len))

				return -EINVAL;

			break;

		case INET_DIAG_BC_MARK_COND:

			if (!net_admin)

				return -EPERM;

			if (!valid_markcond(bc, len, &min_len))

				return -EINVAL;

			break;

		case INET_DIAG_BC_AUTO:

		case INET_DIAG_BC_JMP:

		case INET_DIAG_BC_NOP:
@@ -1030,7 +1060,7 @@ static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh) 


			attr = nlmsg_find_attr(nlh, hdrlen,

					       INET_DIAG_REQ_BYTECODE);

			err = inet_diag_bc_audit(attr);

			err = inet_diag_bc_audit(attr, skb);

			if (err)

				return err;

		}
@@ -1061,7 +1091,7 @@ static int inet_diag_handler_cmd(struct sk_buff *skb, struct nlmsghdr *h) 


			attr = nlmsg_find_attr(h, hdrlen,

					       INET_DIAG_REQ_BYTECODE);

			err = inet_diag_bc_audit(attr);

			err = inet_diag_bc_audit(attr, skb);

			if (err)

				return err;

		}