nss_dns: Check for proper A/AAAA address alignment

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Florian Weimer 2019-05-24 22:14:04 +02:00
parent bee1f2c413
commit 5c23c82195
2 changed files with 18 additions and 2 deletions

View File

@ -1,3 +1,8 @@
2019-05-24 Florian Weimer <fweimer@redhat.com>
* resolv/nss_dns/dns-host.c (getanswer_r): Be more explicit about
struct in_addr/struct in6_addr alignment.
2019-05-23 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/bits/fcntl-linux.h [__USE_GNU]

View File

@ -78,6 +78,7 @@
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <libc-pointer-arith.h>
#include "nsswitch.h"
#include <arpa/nameser.h>
@ -947,8 +948,18 @@ getanswer_r (struct resolv_context *ctx,
linebuflen -= nn;
}
linebuflen -= sizeof (align) - ((u_long) bp % sizeof (align));
bp += sizeof (align) - ((u_long) bp % sizeof (align));
/* Provide sufficient alignment for both address
families. */
enum { align = 4 };
_Static_assert ((align % __alignof__ (struct in_addr)) == 0,
"struct in_addr alignment");
_Static_assert ((align % __alignof__ (struct in6_addr)) == 0,
"struct in6_addr alignment");
{
char *new_bp = PTR_ALIGN_UP (bp, align);
linebuflen -= new_bp - bp;
bp = new_bp;
}
if (__glibc_unlikely (n > linebuflen))
goto too_small;