Re: bind(2) fails on 13.0-STABLE when sin_family is 0

From: Mark Johnston <markj_at_freebsd.org>
Date: Fri, 28 May 2021 18:12:40 -0400
On Fri, May 28, 2021 at 02:40:26PM -0700, Bakul Shah wrote:
> ttcp runs fine on 13.0-RELEASE but fails on -stable.
> 
> The culprit seems to be bind(2). Running ttcp under gdb:
> 
> $ gdb a.out
> Reading symbols from a.out...
> (gdb) b 295
> Breakpoint 1 at 0x203127: file ttcp.c, line 295.
> (gdb) run -s -r
> Starting program: /usr/ports/benchmarks/ttcp/work/ttcp-1.12_2/a.out -s -r
> ttcp-r: buflen=8192, nbuf=2048, align=16384/0, port=5001  tcp
> ttcp-r: socket
> 
> Breakpoint 1, main (argc=3, argv=0x7fffffffd9b0) at ttcp.c:295
> 295             if (bind(fd, (struct sockaddr *) &sinme, sizeof(sinme)) < 0)
> (gdb) p/x sinme
> $1 = {sin_len = 0x0, sin_family = 0x0, sin_port = 0x8913, sin_addr = {
>    s_addr = 0x0}, sin_zero = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}
> (gdb) n
> 296                     err("bind");
> (gdb) p errno
> $2 = 47
> 
> 
> $ errno 47
> #define EAFNOSUPPORT    47              /* Address family not supported by protocol family */
> 
> Did something change post 13.0-RELEASE that requires specifying sin_family?
> Thanks!

Yes, some changes were made recently to make sockaddr validation
stricter.  Several other operating systems also have this requirement.
Linux seems to be a bit more relaxed in that AF_UNSPEC (0) is permitted
if and only if the bind address is INADDR_ANY, which is the case here.

Since 2001 the benchmarks/ttcp port has carried a patch to specify
sin_family.  Is there some reason it cannot be used here?  I don't
object to re-allowing ttcp's unpatched behaviour if necessary.
Received on Fri May 28 2021 - 22:12:40 UTC

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