[PATCH v3] sockaddr.3type: POSIX Issue 8 will solve strict-aliasing issues with these types

[PATCH v3] sockaddr.3type: POSIX Issue 8 will solve strict-aliasing issues with these types

[Alejandro Colomar]

Link: <https://austingroupbugs.net/view.php?id=1641>
Reported-by: Bastien Roucariès <rouca@debian.org>
Reported-by: Alejandro Colomar <alx@kernel.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Cc: glibc <libc-alpha@sourceware.org>
Cc: GCC <gcc@gcc.gnu.org>
Cc: Stefan Puiu <stefan.puiu@gmail.com>
Cc: Igor Sysoev <igor@sysoev.ru>
Cc: Rich Felker <dalias@libc.org>
Cc: Andrew Clayton <andrew@digital-domain.net>
Cc: Richard Biener <richard.guenther@gmail.com>
Cc: Zack Weinberg <zack@owlfolio.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Joseph Myers <joseph@codesourcery.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Sam James <sam@gentoo.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---

Hi Eric,

I took your informal review as a "Reviewed-by".  Please confirm.
I've also modified the small wording thingy you suggested.

I'll float this patch in the list in case anyone has comments, and
will push some time this weekend (depending on many variables).

Cheers,
Alex

 man3type/sockaddr.3type | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/man3type/sockaddr.3type b/man3type/sockaddr.3type
index 2fdf56c59..cf8d601f5 100644
--- a/man3type/sockaddr.3type
+++ b/man3type/sockaddr.3type
@@ -117,6 +117,14 @@ .SH HISTORY
 was invented by POSIX.
 See also
 .BR accept (2).
+.PP
+These structures were invented before modern ISO C strict-aliasing rules.
+If aliasing rules are applied strictly,
+these structures would be extremely difficult to use
+without invoking Undefined Behavior.
+POSIX Issue 8 will fix this by requiring that implementations
+make sure that these structures
+can be safely used as they were designed.
 .SH NOTES
 .I socklen_t
 is also defined in
-- 
2.40.0

Re: [PATCH v3] sockaddr.3type: POSIX Issue 8 will solve strict-aliasing issues with these types

[Eric Blake]

On Fri, Apr 21, 2023 at 10:27:18PM +0200, Alejandro Colomar wrote:
> Link: <https://austingroupbugs.net/view.php?id=1641>
> Reported-by: Bastien Roucariès <rouca@debian.org>
> Reported-by: Alejandro Colomar <alx@kernel.org>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Cc: glibc <libc-alpha@sourceware.org>
> Cc: GCC <gcc@gcc.gnu.org>
> Cc: Stefan Puiu <stefan.puiu@gmail.com>
> Cc: Igor Sysoev <igor@sysoev.ru>
> Cc: Rich Felker <dalias@libc.org>
> Cc: Andrew Clayton <andrew@digital-domain.net>
> Cc: Richard Biener <richard.guenther@gmail.com>
> Cc: Zack Weinberg <zack@owlfolio.org>
> Cc: Florian Weimer <fweimer@redhat.com>
> Cc: Joseph Myers <joseph@codesourcery.com>
> Cc: Jakub Jelinek <jakub@redhat.com>
> Cc: Sam James <sam@gentoo.org>
> Signed-off-by: Alejandro Colomar <alx@kernel.org>
> ---
> 
> Hi Eric,
> 
> I took your informal review as a "Reviewed-by".  Please confirm.
> I've also modified the small wording thingy you suggested.

For the avoidance of doubt ;)

Reviewed-by: Eric Blake <eblake@redhat.com>


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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