From: Mark Wielaard <mark@klomp.org>
Date: Mon, 27 Mar 2017 21:59:02 +0000 (+0200)
Subject: elflint: Check symbol table data is big enough before checking.
X-Git-Tag: elfutils-0.169~30
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9a0d9d314a6342b56e3277bd7ad7ecb6e73a7d38;p=thirdparty%2Felfutils.git

elflint: Check symbol table data is big enough before checking.

Before checking symbol index zero we should make sure the data size
is big enough.

https://sourceware.org/bugzilla/show_bug.cgi?id=21310

Signed-off-by: Mark Wielaard <mark@klomp.org>
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 41381aa03..6031213f0 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2017-03-27  Mark Wielaard  <mark@klomp.org>
+
+	* elflint.c (check_symtab_shndx): Check data->d_size.
+
 2017-03-24  Mark Wielaard  <mjw@redhat.com>
 
 	* elfcmp.c (main): If n_namesz == 0 then the note name data is the
diff --git a/src/elflint.c b/src/elflint.c
index 66a13ca22..76fb1a0c5 100644
--- a/src/elflint.c
+++ b/src/elflint.c
@@ -1959,7 +1959,8 @@ section [%2d] '%s': extended section index in section [%2zu] '%s' refers to same
       return;
     }
 
-  if (*((Elf32_Word *) data->d_buf) != 0)
+  if (data->d_size < sizeof (Elf32_Word)
+      || *((Elf32_Word *) data->d_buf) != 0)
     ERROR (gettext ("symbol 0 should have zero extended section index\n"));
 
   for (size_t cnt = 1; cnt < data->d_size / sizeof (Elf32_Word); ++cnt)