CVE-2016-3075: Stack overflow in _nss_dns_getnetbyname_r [BZ #19879]

The defensive copy is not needed because the name may not alias the output buffer.
git-mirror · Mar 29, 2016 · 317b199 · 317b199
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diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,10 @@
+2016-03-29  Florian Weimer  <fweimer@redhat.com>
+
+	[BZ #19879]
+	CVE-2016-3075
+	* resolv/nss_dns/dns-network.c (_nss_dns_getnetbyname_r): Do not
+	copy name.
+
 2016-03-29  Florian Weimer  <fweimer@redhat.com>
 
 	[BZ #19837]

diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c
@@ -118,17 +118,14 @@ _nss_dns_getnetbyname_r (const char *name, struct netent *result,
   } net_buffer;
   querybuf *orig_net_buffer;
   int anslen;
-  char *qbuf;
   enum nss_status status;
 
   if (__res_maybe_init (&_res, 0) == -1)
     return NSS_STATUS_UNAVAIL;
 
-  qbuf = strdupa (name);
-
   net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
 
-  anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
+  anslen = __libc_res_nsearch (&_res, name, C_IN, T_PTR, net_buffer.buf->buf,
 			       1024, &net_buffer.ptr, NULL, NULL, NULL, NULL);
   if (anslen < 0)
     {