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Subject[PATCH net] ipv4: ping: fix bind address validity check
From
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").

[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>
Cc: Riccardo Paolo Bestetti <pbl@bestov.io>
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
net/ipv4/ping.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 1a43ca73f94d..3c6101def7d6 100644
--- 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)
--
2.36.1.476.g0c4daa206d-goog
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