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

[David Ahern]

On 3/20/21 6:20 PM, Riccardo Paolo Bestetti wrote:
> diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
> index 50a73178d63a..734c0332b54b 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;
> @@ -732,7 +733,8 @@ static int raw_bind(struct sock *sk, struct sockaddr 
> *uaddr, int addr_len)
>   tb_id);
>  
>   ret = -EADDRNOTAVAIL;
> - if (addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
> + if (!inet_can_nonlocal_bind(net, inet) &&
> + addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
>   chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
>   goto out;
>   inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
> 


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.

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.

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

[Riccardo Paolo Bestetti]

Add support to inet 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.

Signed-off-by: Riccardo Paolo Bestetti 
---
 net/ipv4/raw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 50a73178d63a..734c0332b54b 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;
@@ -732,7 +733,8 @@ static int raw_bind(struct sock *sk, struct sockaddr 
*uaddr, int addr_len)
tb_id);
 
ret = -EADDRNOTAVAIL;
-   if (addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
+   if (!inet_can_nonlocal_bind(net, inet) &&
+   addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
goto out;
inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
-- 
2.31.0