ipv4: ping: fix bind address validity check

Commit 8ff978b8b222 ("ipv4/raw: support binding to nonlocal addresses")
introduced a helper function to fold duplicated validity checks of bind
addresses into inet_addr_valid_or_nonlocal(). However, this caused an
unintended regression in ping_check_bind_addr(), which previously would
reject binding to multicast and broadcast addresses, but now these are
both incorrectly allowed as reported in [1].

This patch restores the original check. A simple reordering is done to
improve readability and make it evident that multicast and broadcast
addresses should not be allowed. Also, add an early exit for INADDR_ANY
which replaces lost behavior added by commit 0ce779a9f501 ("net: Avoid
unnecessary inet_addr_type() call when addr is INADDR_ANY").

Furthermore, this patch introduces regression selftests to catch these
specific cases.

[1] https://lore.kernel.org/netdev/CANP3RGdkAcDyAZoT1h8Gtuu0saq+eOrrTiWbxnOs+5zn+cpyKg@mail.gmail.com/

Fixes: 8ff978b8b222 ("ipv4/raw: support binding to nonlocal addresses")
Cc: Miaohe Lin <linmiaohe@huawei.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Riccardo Paolo Bestetti <pbl@bestov.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 1a43ca7..3c6101d 100644 (file)
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -319,12 +319,16 @@ 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))
+                       return 0;
+
                tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
                chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
 
-               if (!inet_addr_valid_or_nonlocal(net, inet_sk(sk),
-                                                addr->sin_addr.s_addr,
-                                                chk_addr_ret))
+               if (chk_addr_ret == RTN_MULTICAST ||
+                   chk_addr_ret == RTN_BROADCAST ||
+                   (chk_addr_ret != RTN_LOCAL &&
+                    !inet_can_nonlocal_bind(net, isk)))
                        return -EADDRNOTAVAIL;
 
 #if IS_ENABLED(CONFIG_IPV6)

diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh
index 54701c8..75223b6 100755 (executable)
--- a/tools/testing/selftests/net/fcnal-test.sh
+++ b/tools/testing/selftests/net/fcnal-test.sh
@@ -70,6 +70,10 @@ NSB_LO_IP6=2001:db8:2::2
 NL_IP=172.17.1.1
 NL_IP6=2001:db8:4::1
 
+# multicast and broadcast addresses
+MCAST_IP=224.0.0.1
+BCAST_IP=255.255.255.255
+
 MD5_PW=abc123
 MD5_WRONG_PW=abc1234
 
@@ -308,6 +312,9 @@ addr2str()
        127.0.0.1) echo "loopback";;
        ::1) echo "IPv6 loopback";;
 
+       ${BCAST_IP}) echo "broadcast";;
+       ${MCAST_IP}) echo "multicast";;
+
        ${NSA_IP})      echo "ns-A IP";;
        ${NSA_IP6})     echo "ns-A IPv6";;
        ${NSA_LO_IP})   echo "ns-A loopback IP";;
@@ -1801,6 +1808,19 @@ ipv4_addr_bind_novrf()
        log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address after device bind"
 
        #
+       # check that ICMP sockets cannot bind to broadcast and multicast addresses
+       #
+       a=${BCAST_IP}
+       log_start
+       run_cmd nettest -s -R -P icmp -l ${a} -b
+       log_test_addr ${a} $? 1 "ICMP socket bind to broadcast address"
+
+       a=${MCAST_IP}
+       log_start
+       run_cmd nettest -s -R -P icmp -f -l ${a} -b
+       log_test_addr ${a} $? 1 "ICMP socket bind to multicast address"
+
+       #
        # tcp sockets
        #
        a=${NSA_IP}
@@ -1858,6 +1878,19 @@ ipv4_addr_bind_vrf()
        log_test_addr ${a} $? 0 "Raw socket bind to nonlocal address after VRF bind"
 
        #
+       # check that ICMP sockets cannot bind to broadcast and multicast addresses
+       #
+       a=${BCAST_IP}
+       log_start
+       run_cmd nettest -s -R -P icmp -l ${a} -I ${VRF} -b
+       log_test_addr ${a} $? 1 "ICMP socket bind to broadcast address after VRF bind"
+
+       a=${MCAST_IP}
+       log_start
+       run_cmd nettest -s -R -P icmp -f -l ${a} -I ${VRF} -b
+       log_test_addr ${a} $? 1 "ICMP socket bind to multicast address after VRF bind"
+
+       #
        # tcp sockets
        #
        for a in ${NSA_IP} ${VRF_IP}