Re: [PATCH v2] ipv4/raw: support binding to nonlocal addresses

[Denis Kirjanov]

11/17/21 12:00 PM, Riccardo Paolo Bestetti пишет:
> Add support to inet v4 raw sockets for binding to nonlocal addresses
> through the IP_FREEBIND and IP_TRANSPARENT socket options, as well as
> the ipv4.ip_nonlocal_bind kernel parameter.
>
> Add helper function to inet_sock.h to check for bind address validity on
> the base of the address type and whether nonlocal address are enabled
> for the socket via any of the sockopts/sysctl, deduplicating checks in
> ipv4/ping.c, ipv4/af_inet.c, ipv6/af_inet6.c (for mapped v4->v6
> addresses), and ipv4/raw.c.
>
> Add test cases with IP[V6]_FREEBIND verifying that both v4 and v6 raw
> sockets support binding to nonlocal addresses after the change. Add
> necessary support for the test cases to nettest.
>
> Signed-off-by: Riccardo Paolo Bestetti <pbl@xxxxxxxxx>
> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
> ---
> 20211117: resending this, as Patchwork didn't pick it up last time
>
> Responding to review by David Ahern (21 March 2021),
>
> Thank you for your review.
>
> > Please add test cases to ipv4_addr_bind and ipv6_addr_bind in
> > tools/testing/selftests/net/fcnal-test.sh. The latter will verify if
> > IPv6 works the same or needs a change.
> I have added the tests for both v4 and v6.  IPv6 raw sockets already
> supported the functionality (under the IPV6_* sockopts), and the (new)
> related tests pass, confirming this.
>
> I have not added negative tests (i.e. checking that the same addresses
> /fail/ to bind without the necessary flags) because I haven't seen such
> tests for other features.  If you feel that's needed, I can look into
> it.
>
> > Also, this check duplicates the ones in __inet_bind and __inet6_bind; it
> > would be good to use an inline helper to reduce the duplication.
> Done.  The same check was also duplicated in net/ipv4/ping.c, as
> detailed in the commit message.  I have also deduplicated that, if it
> should have been left alone I'll quickly fire up a v3 and revert that.
>
> Sorry for the delay with v2, had a busy year.
>
>
>   include/net/inet_sock.h                   | 12 +++++++
>   net/ipv4/af_inet.c                        |  7 ++--
>   net/ipv4/ping.c                           | 14 +++-----
>   net/ipv4/raw.c                            | 13 ++++----
>   net/ipv6/af_inet6.c                       |  7 ++--
>   tools/testing/selftests/net/fcnal-test.sh | 40 +++++++++++++++++++++++
>   tools/testing/selftests/net/nettest.c     | 33 ++++++++++++++++++-
>   7 files changed, 100 insertions(+), 26 deletions(-)
>
> diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
> index 89163ef8cf4b..13b05d116f6b 100644
> --- a/include/net/inet_sock.h
> +++ b/include/net/inet_sock.h
> @@ -373,4 +373,16 @@ static inline bool inet_can_nonlocal_bind(struct net *net,
>   		inet->freebind || inet->transparent;
>   }
>   
> +static inline bool inet_addr_valid_or_nonlocal(struct net *net,
> +					       struct inet_sock *inet,
> +					       __be32 addr,
> +					       int addr_type)
> +{
> +	return inet_can_nonlocal_bind(net, inet) ||
> +		addr == htonl(INADDR_ANY) ||
> +		addr_type == RTN_LOCAL ||
> +		addr_type == RTN_MULTICAST ||
> +		addr_type == RTN_BROADCAST;
> +}
> +
>   #endif	/* _INET_SOCK_H */
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 1d816a5fd3eb..fb5cf3623e03 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -492,11 +492,8 @@ int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
>   	 *  is temporarily down)
>   	 */
>   	err = -EADDRNOTAVAIL;
> -	if (!inet_can_nonlocal_bind(net, inet) &&
> -	    addr->sin_addr.s_addr != htonl(INADDR_ANY) &&
> -	    chk_addr_ret != RTN_LOCAL &&
> -	    chk_addr_ret != RTN_MULTICAST &&
> -	    chk_addr_ret != RTN_BROADCAST)
> +	if (!inet_addr_valid_or_nonlocal(net, inet, addr->sin_addr.s_addr,
> +	                                 chk_addr_ret))
>   		goto out;
>   
>   	snum = ntohs(addr->sin_port);
> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> index 1e44a43acfe2..e540b0dcf085 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -311,15 +311,11 @@ static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
>   		pr_debug("ping_check_bind_addr(sk=%p,addr=%pI4,port=%d)\n",
>   			 sk, &addr->sin_addr.s_addr, ntohs(addr->sin_port));
>   
> -		if (addr->sin_addr.s_addr == htonl(INADDR_ANY))
> -			chk_addr_ret = RTN_LOCAL;
> -		else
> -			chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);

That was done intentionally in commit 0ce779a9f501

> -
> -		if ((!inet_can_nonlocal_bind(net, isk) &&
> -		     chk_addr_ret != RTN_LOCAL) ||
> -		    chk_addr_ret == RTN_MULTICAST ||
> -		    chk_addr_ret == RTN_BROADCAST)
> +		chk_addr_ret = inet_addr_type(net, addr->sin_addr.s_addr);
> +
> +		if (!inet_addr_valid_or_nonlocal(net, inet_sk(sk),
> +					         addr->sin_addr.s_addr,
> +	                                         chk_addr_ret))
>   			return -EADDRNOTAVAIL;
>   
>   #if IS_ENABLED(CONFIG_IPV6)
> diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> index bb446e60cf58..fa60517372b5 100644
> --- a/net/ipv4/raw.c
> +++ b/net/ipv4/raw.c
> @@ -717,6 +717,7 @@ static int raw_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
>   {
>   	struct inet_sock *inet = inet_sk(sk);
>   	struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
> +	struct net *net = sock_net(sk);
>   	u32 tb_id = RT_TABLE_LOCAL;
>   	int ret = -EINVAL;
>   	int chk_addr_ret;
> @@ -725,16 +726,16 @@ static int raw_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
>   		goto out;
>   
>   	if (sk->sk_bound_dev_if)
> -		tb_id = l3mdev_fib_table_by_index(sock_net(sk),
> -						 sk->sk_bound_dev_if) ? : tb_id;
> +		tb_id = l3mdev_fib_table_by_index(net,
> +						  sk->sk_bound_dev_if) ? : tb_id;
>   
> -	chk_addr_ret = inet_addr_type_table(sock_net(sk), addr->sin_addr.s_addr,
> -					    tb_id);
> +	chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
>   
>   	ret = -EADDRNOTAVAIL;
> -	if (addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
> -	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
> +	if (!inet_addr_valid_or_nonlocal(net, inet, addr->sin_addr.s_addr,
> +					 chk_addr_ret))
>   		goto out;
> +
>   	inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
>   	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
>   		inet->inet_saddr = 0;  /* Use device */
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index b5878bb8e419..0c557edbbd20 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -337,11 +337,8 @@ static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
>   		chk_addr_ret = inet_addr_type_dev_table(net, dev, v4addr);
>   		rcu_read_unlock();
>   
> -		if (!inet_can_nonlocal_bind(net, inet) &&
> -		    v4addr != htonl(INADDR_ANY) &&
> -		    chk_addr_ret != RTN_LOCAL &&
> -		    chk_addr_ret != RTN_MULTICAST &&
> -		    chk_addr_ret != RTN_BROADCAST) {
> +		if (!inet_addr_valid_or_nonlocal(net, inet, v4addr,
> +						 chk_addr_ret)) {
>   			err = -EADDRNOTAVAIL;
>   			goto out;
>   		}
> diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh
> index 3313566ce906..7caa4f0e067d 100755
> --- a/tools/testing/selftests/net/fcnal-test.sh
> +++ b/tools/testing/selftests/net/fcnal-test.sh
> @@ -66,6 +66,10 @@ NSB_LO_IP=172.16.2.2
>   NSA_LO_IP6=2001:db8:2::1
>   NSB_LO_IP6=2001:db8:2::2
>   
> +# non-local addresses for freebind tests
> +NL_IP=172.17.1.1
> +NL_IP6=2001:db8:4::1
> +
>   MD5_PW=abc123
>   MD5_WRONG_PW=abc1234
>   
> @@ -316,6 +320,9 @@ addr2str()
>   	${NSB_LO_IP6})	echo "ns-B loopback IPv6";;
>   	${NSB_LINKIP6}|${NSB_LINKIP6}%*) echo "ns-B IPv6 LLA";;
>   
> +	${NL_IP})       echo "nonlocal IP";;
> +	${NL_IP6})      echo "nonlocal IPv6";;
> +
>   	${VRF_IP})	echo "VRF IP";;
>   	${VRF_IP6})	echo "VRF IPv6";;
>   
> @@ -1767,6 +1774,14 @@ ipv4_addr_bind_novrf()
>   		log_test_addr ${a} $? 0 "Raw socket bind to local address after device bind"
>   	done
>   
> +	#
> +	# raw socket with nonlocal bind
> +	#
> +	a=${NL_IP}
> +	log_start
> +	run_cmd nettest -s -R -P icmp -f -l ${a} -I ${NSA_DEV} -b
> +	log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address after device bind"
> +
>   	#
>   	# tcp sockets
>   	#
> @@ -1815,6 +1830,14 @@ ipv4_addr_bind_vrf()
>   	run_cmd nettest -s -R -P icmp -l ${a} -I ${VRF} -b
>   	log_test_addr ${a} $? 1 "Raw socket bind to out of scope address after VRF bind"
>   
> +	#
> +	# raw socket with nonlocal bind
> +	#
> +	a=${NL_IP}
> +	log_start
> +	run_cmd nettest -s -R -P icmp -f -l ${a} -I ${VRF} -b
> +	log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address after VRF bind"
> +
>   	#
>   	# tcp sockets
>   	#
> @@ -1965,6 +1988,7 @@ ipv4_rt()
>   
>   	a=${NSA_IP}
>   	log_start
> +
>   	run_cmd nettest ${varg} -s &
>   	sleep 1
>   	run_cmd nettest ${varg} -d ${NSA_DEV} -r ${a} &
> @@ -3402,6 +3426,14 @@ ipv6_addr_bind_novrf()
>   		log_test_addr ${a} $? 0 "Raw socket bind to local address after device bind"
>   	done
>   
> +	#
> +	# raw socket with nonlocal bind
> +	#
> +	a=${NL_IP6}
> +	log_start
> +	run_cmd nettest -6 -s -R -P icmp -f -l ${a} -I ${NSA_DEV} -b
> +	log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address"
> +
>   	#
>   	# tcp sockets
>   	#
> @@ -3443,6 +3475,14 @@ ipv6_addr_bind_vrf()
>   	run_cmd nettest -6 -s -R -P ipv6-icmp -l ${a} -I ${VRF} -b
>   	log_test_addr ${a} $? 1 "Raw socket bind to invalid local address after vrf bind"
>   
> +	#
> +	# raw socket with nonlocal bind
> +	#
> +	a=${NL_IP6}
> +	log_start
> +	run_cmd nettest -6 -s -R -P icmp -f -l ${a} -I ${VRF} -b
> +	log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address after VRF bind"
> +
>   	#
>   	# tcp sockets
>   	#
> diff --git a/tools/testing/selftests/net/nettest.c b/tools/testing/selftests/net/nettest.c
> index b599003eb5ba..d9a6fd2cd9d3 100644
> --- a/tools/testing/selftests/net/nettest.c
> +++ b/tools/testing/selftests/net/nettest.c
> @@ -85,6 +85,7 @@ struct sock_args {
>   	int version;   /* AF_INET/AF_INET6 */
>   
>   	int use_setsockopt;
> +	int use_freebind;
>   	int use_cmsg;
>   	const char *dev;
>   	const char *server_dev;
> @@ -514,6 +515,29 @@ static int set_membership(int sd, uint32_t grp, uint32_t addr, int ifindex)
>   	return 0;
>   }
>   
> +static int set_freebind(int sd, int version)
> +{
> +	unsigned int one = 1;
> +	int rc = 0;
> +
> +	switch (version) {
> +	case AF_INET:
> +		if (setsockopt(sd, SOL_IP, IP_FREEBIND, &one, sizeof(one))) {
> +			log_err_errno("setsockopt(IP_FREEBIND)");
> +			rc = -1;
> +		}
> +		break;
> +	case AF_INET6:
> +		if (setsockopt(sd, SOL_IPV6, IPV6_FREEBIND, &one, sizeof(one))) {
> +			log_err_errno("setsockopt(IPV6_FREEBIND");
> +			rc = -1;
> +		}
> +		break;
> +	}
> +
> +	return rc;
> +}
> +
>   static int set_broadcast(int sd)
>   {
>   	unsigned int one = 1;
> @@ -1419,6 +1443,9 @@ static int lsock_init(struct sock_args *args)
>   		 set_unicast_if(sd, args->ifindex, args->version))
>   		goto err;
>   
> +	if (args->use_freebind && set_freebind(sd, args->version))
> +		goto err;
> +
>   	if (bind_socket(sd, args))
>   		goto err;
>   
> @@ -1827,7 +1854,7 @@ static int ipc_parent(int cpid, int fd, struct sock_args *args)
>   	return client_status;
>   }
>   
> -#define GETOPT_STR  "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6xL:0:1:2:3:Fbq"
> +#define GETOPT_STR  "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6xL:0:1:2:3:Fbqf"
>   #define OPT_FORCE_BIND_KEY_IFINDEX 1001
>   #define OPT_NO_BIND_KEY_IFINDEX 1002
>   
> @@ -1864,6 +1891,7 @@ static void print_usage(char *prog)
>   	"    -I dev        bind socket to given device name - server mode\n"
>   	"    -S            use setsockopt (IP_UNICAST_IF or IP_MULTICAST_IF)\n"
>   	"                  to set device binding\n"
> +	"    -f            bind socket with the IP[V6]_FREEBIND option\n"
>   	"    -C            use cmsg and IP_PKTINFO to specify device binding\n"
>   	"\n"
>   	"    -L len        send random message of given length\n"
> @@ -1999,6 +2027,9 @@ int main(int argc, char *argv[])
>   		case 'S':
>   			args.use_setsockopt = 1;
>   			break;
> +		case 'f':
> +			args.use_freebind = 1;
> +			break;
>   		case 'C':
>   			args.use_cmsg = 1;
>   			break;