This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH] nss_dns: Check for proper A/AAAA address alignment
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Thu, 16 May 2019 20:18:27 +0200
- Subject: [PATCH] nss_dns: Check for proper A/AAAA address alignment
2019-05-16 Florian Weimer <fweimer@redhat.com>
* resolv/nss_dns/dns-host.c (getanswer_r): Be more explicit about
struct in_addr/struct in6_addr alignment.
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 9c15f25f28..9c40051aff 100644
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -947,8 +947,15 @@ 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");
+ linebuflen -= align - ((u_long) bp % align);
+ bp += align - ((u_long) bp % align);
if (__glibc_unlikely (n > linebuflen))
goto too_small;