CVE-2015-1781: resolv/nss_dns/dns-host.c buffer overflow [BZ#18287]

Change-Id: I4104608d09d17826cd863877e1f0cdaffaecfe7f
Signed-off-by: Hyung-Kyu (HQ) Choi <hk0110.choi@samsung.com>

diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
index 755832e..1a04900 100644 (file)
--- a/resolv/nss_dns/dns-host.c
+++ b/resolv/nss_dns/dns-host.c
@@ -615,7 +615,8 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
   int have_to_map = 0;
   uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data);
   buffer += pad;
-  if (__glibc_unlikely (buflen < sizeof (struct host_data) + pad))
+  buflen = buflen > pad ? buflen - pad : 0;
+  if (__glibc_unlikely (buflen < sizeof (struct host_data)))
     {
       /* The buffer is too small.  */
     too_small: