[OE-core] [PATCH 2/2] glibc: CVE-2015-1781: resolv/nss_dns/dns-host.c buffer overflow

[Haris Okanovic]

Backport Arjun Shankar's patch for CVE-2015-1781:

A buffer overflow flaw was found in the way glibc's gethostbyname_r() and
other related functions computed the size of a buffer when passed a
misaligned buffer as input. An attacker able to make an application call
any of these functions with a misaligned buffer could use this flaw to
crash the application or, potentially, execute arbitrary code with the
permissions of the user running the application.

https://sourceware.org/bugzilla/show_bug.cgi?id=18287

Signed-off-by: Haris Okanovic <haris.okanovic at ni.com>
Signed-off-by: Ken Sharp <ken.sharp at ni.com>
Reviewed-by: Rich Tollerton <rich.tollerton at ni.com>
---
Natinst-CAR-ID: 525428
Natinst-ReviewBoard-ID: 96712
---
 ...81-resolv-nss_dns-dns-host.c-buffer-overf.patch | 43 ++++++++++++++++++++++
 meta/recipes-core/glibc/glibc_2.20.bb              |  1 +
 2 files changed, 44 insertions(+)
 create mode 100644 meta/recipes-core/glibc/glibc/CVE-2015-1781-resolv-nss_dns-dns-host.c-buffer-overf.patch

diff --git a/meta/recipes-core/glibc/glibc/CVE-2015-1781-resolv-nss_dns-dns-host.c-buffer-overf.patch b/meta/recipes-core/glibc/glibc/CVE-2015-1781-resolv-nss_dns-dns-host.c-buffer-overf.patch
new file mode 100644
index 0000000..c02fa12
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/CVE-2015-1781-resolv-nss_dns-dns-host.c-buffer-overf.patch
@@ -0,0 +1,43 @@
+From 2959eda9272a033863c271aff62095abd01bd4e3 Mon Sep 17 00:00:00 2001
+From: Arjun Shankar <arjun.is at lostca.se>
+Date: Tue, 21 Apr 2015 14:06:31 +0200
+Subject: [PATCH] CVE-2015-1781: resolv/nss_dns/dns-host.c buffer overflow
+ [BZ#18287]
+
+Upstream-Status: Backport
+https://sourceware.org/bugzilla/show_bug.cgi?id=18287
+---
+ resolv/nss_dns/dns-host.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c
+index b16b0ddf110907a0086b86612e544d3dc75182b8..d8c55791591750567f00e616e5d7b378dec934a0 100644
+--- a/resolv/nss_dns/dns-host.c
++++ b/resolv/nss_dns/dns-host.c
+@@ -608,21 +608,22 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
+   int n, ancount, qdcount;
+   int haveanswer, had_error;
+   char *bp, **ap, **hap;
+   char tbuf[MAXDNAME];
+   const char *tname;
+   int (*name_ok) (const char *);
+   u_char packtmp[NS_MAXCDNAME];
+   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:
+       *errnop = ERANGE;
+       *h_errnop = NETDB_INTERNAL;
+       return NSS_STATUS_TRYAGAIN;
+     }
+   host_data = (struct host_data *) buffer;
+   linebuflen = buflen - sizeof (struct host_data);
+   if (buflen - sizeof (struct host_data) != linebuflen)
+-- 
+2.2.2
+
diff --git a/meta/recipes-core/glibc/glibc_2.20.bb b/meta/recipes-core/glibc/glibc_2.20.bb
index e3427dd..ba62fc3 100644
--- a/meta/recipes-core/glibc/glibc_2.20.bb
+++ b/meta/recipes-core/glibc/glibc_2.20.bb
@@ -47,6 +47,7 @@ CVEPATCHES = "\
         file://CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch \
         file://CVE-2014-9402_endless-loop-in-getaddr_r.patch \
         file://CVE-2015-1472-wscanf-allocates-too-little-memory.patch \
+        file://CVE-2015-1781-resolv-nss_dns-dns-host.c-buffer-overf.patch \
     "
 LIC_FILES_CHKSUM = "file://LICENSES;md5=e9a558e243b36d3209f380deb394b213 \
       file://COPYING;md5=b234ee4d69f5fce4486a80fdaf4a4263 \
-- 
2.2.2