about summary refs log tree commit diff
path: root/resolv
diff options
context:
space:
mode:
authorFlorian Weimer <fweimer@redhat.com>2019-05-24 22:14:04 +0200
committerFlorian Weimer <fweimer@redhat.com>2019-05-24 22:14:04 +0200
commit5c23c82195fc9e95ae34180250f64438f1e6fb0b (patch)
tree3f0d15867781144e230a9aa8cb3f69277fc18493 /resolv
parentbee1f2c413ef0cf99d25f898fa0eb0d41fb71dc5 (diff)
downloadglibc-5c23c82195fc9e95ae34180250f64438f1e6fb0b.tar.gz
glibc-5c23c82195fc9e95ae34180250f64438f1e6fb0b.tar.xz
glibc-5c23c82195fc9e95ae34180250f64438f1e6fb0b.zip
nss_dns: Check for proper A/AAAA address alignment
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'resolv')
-rw-r--r--resolv/nss_dns/dns-host.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 9c15f25f28..5af47fd10d 100644
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -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;