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    Subject[PATCH 5.18 013/181] ipv4: ping: fix bind address validity check
    Date
    From: Riccardo Paolo Bestetti <pbl@bestov.io>

    commit b4a028c4d031c27704ad73b1195ca69a1206941e upstream.

    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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/ipv4/ping.c | 10 ++++++---
    tools/testing/selftests/net/fcnal-test.sh | 33 ++++++++++++++++++++++++++++++
    2 files changed, 40 insertions(+), 3 deletions(-)

    --- a/net/ipv4/ping.c
    +++ b/net/ipv4/ping.c
    @@ -319,12 +319,16 @@ static int ping_check_bind_addr(struct s
    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)
    --- 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}

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