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From eef104664efb52965d85a28bc3fc7c77e52e48e2 Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Wed, 28 Feb 2018 10:13:54 +0000
Subject: [PATCH] Fix potential integer overflow when reading corrupt dwarf1
debug information.
PR 22894
* dwarf1.c (parse_die): Check the length of form blocks before
advancing the data pointer.
Upstream-Status: Backport
Affects: <= 2.30
CVE: CVE-2018-7568 patch2
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
bfd/ChangeLog | 6 ++++++
bfd/dwarf1.c | 17 +++++++++++++++--
2 files changed, 21 insertions(+), 2 deletions(-)
Index: git/bfd/dwarf1.c
===================================================================
--- git.orig/bfd/dwarf1.c
+++ git/bfd/dwarf1.c
@@ -213,6 +213,7 @@ parse_die (bfd * abfd,
/* Then the attributes. */
while (xptr + 2 <= aDiePtrEnd)
{
+ unsigned int block_len;
unsigned short attr;
/* Parse the attribute based on its form. This section
@@ -255,12 +256,24 @@ parse_die (bfd * abfd,
break;
case FORM_BLOCK2:
if (xptr + 2 <= aDiePtrEnd)
- xptr += bfd_get_16 (abfd, xptr);
+ {
+ block_len = bfd_get_16 (abfd, xptr);
+ if (xptr + block_len > aDiePtrEnd
+ || xptr + block_len < xptr)
+ return FALSE;
+ xptr += block_len;
+ }
xptr += 2;
break;
case FORM_BLOCK4:
if (xptr + 4 <= aDiePtrEnd)
- xptr += bfd_get_32 (abfd, xptr);
+ {
+ block_len = bfd_get_32 (abfd, xptr);
+ if (xptr + block_len > aDiePtrEnd
+ || xptr + block_len < xptr)
+ return FALSE;
+ xptr += block_len;
+ }
xptr += 4;
break;
case FORM_STRING:
Index: git/bfd/ChangeLog
===================================================================
--- git.orig/bfd/ChangeLog
+++ git/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2018-02-28 Nick Clifton <nickc@redhat.com>
+
+ PR 22894
+ * dwarf1.c (parse_die): Check the length of form blocks before
+ advancing the data pointer.
+
2017-09-25 Alan Modra <amodra@gmail.com>
PR 22202
|
