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.

(cherry picked from commit 317b199b4aff8cfa27f2302ab404d2bb5032b9a4)

diff --git a/ChangeLog b/ChangeLog
index 3e0d69b6acc649ecaeb64a8f0fc772d92993c63a..c262784531d4a9d1cc426acd2b433f4f24593101 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-04-01  Florian Weimer  <fweimer@redhat.com>
+
+       [BZ #19879]
+       CVE-2016-3075
+       * resolv/nss_dns/dns-network.c (_nss_dns_getnetbyname_r): Do not
+       copy name.
+
 2016-03-25  Florian Weimer  <fweimer@redhat.com>
 
        [BZ #19791]

diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c
index 00f4490c5d02d5237607990761017f815f01634b..89f8783fbea4af7a60d15b7fcb2b9902c448254c 100644 (file)
--- 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)
     {