From 489246368e2c49a795ad5ecbc8895cbc854292fa Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Fri, 17 Feb 2017 15:59:45 +0000
Subject: Fix illegal memory accesses in readelf when parsing a corrupt binary.

	PR binutils/21156
	* readelf.c (find_section_in_set): Test for invalid section
	indicies.

CVE: CVE-2017-6969
Upstream-Status: Backport [master]

Signed-off-by: Yuanjie Huang <yuanjie.huang@windriver.com>
---
 binutils/ChangeLog |  6 ++++++
 binutils/readelf.c | 10 ++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index a70bdb7a7b..dbf8eb079e 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,9 @@
+2017-02-17  Nick Clifton  <nickc@redhat.com>
+
+	PR binutils/21156
+	* readelf.c (find_section_in_set): Test for invalid section
+	indicies.
+
 2016-08-03  Tristan Gingold  <gingold@adacore.com>
 
 	* configure: Regenerate.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index d31558c3b4..7f7365dbc5 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -674,8 +674,14 @@ find_section_in_set (const char * name, unsigned int * set)
   if (set != NULL)
     {
       while ((i = *set++) > 0)
-	if (streq (SECTION_NAME (section_headers + i), name))
-	  return section_headers + i;
+	{
+	  /* See PR 21156 for a reproducer.  */
+	  if (i >= elf_header.e_shnum)
+	    continue; /* FIXME: Should we issue an error message ?  */
+
+	  if (streq (SECTION_NAME (section_headers + i), name))
+	    return section_headers + i;
+	}
     }
 
   return find_section (name);
-- 
2.11.0

