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From a941291cab71b9ac356e1c03968c177c03e602ab Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Sat, 29 Apr 2017 14:48:16 +0930
Subject: [PATCH] PR21432, buffer overflow in perform_relocation
The existing reloc offset range tests didn't catch small negative
offsets less than the size of the reloc field.
PR 21432
* reloc.c (reloc_offset_in_range): New function.
(bfd_perform_relocation, bfd_install_relocation): Use it.
(_bfd_final_link_relocate): Likewise.
Upstream-Status: Backport
CVE: CVE-2017-8396
CVE: CVE-2017-8397
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
bfd/ChangeLog | 7 +++++++
bfd/reloc.c | 32 ++++++++++++++++++++------------
2 files changed, 27 insertions(+), 12 deletions(-)
Index: git/bfd/reloc.c
===================================================================
--- git.orig/bfd/reloc.c
+++ git/bfd/reloc.c
@@ -538,6 +538,22 @@ bfd_check_overflow (enum complain_overfl
return flag;
}
+/* HOWTO describes a relocation, at offset OCTET. Return whether the
+ relocation field is within SECTION of ABFD. */
+
+static bfd_boolean
+reloc_offset_in_range (reloc_howto_type *howto, bfd *abfd,
+ asection *section, bfd_size_type octet)
+{
+ bfd_size_type octet_end = bfd_get_section_limit_octets (abfd, section);
+ bfd_size_type reloc_size = bfd_get_reloc_size (howto);
+
+ /* The reloc field must be contained entirely within the section.
+ Allow zero length fields (marker relocs or NONE relocs where no
+ relocation will be performed) at the end of the section. */
+ return octet <= octet_end && octet + reloc_size <= octet_end;
+}
+
/*
FUNCTION
bfd_perform_relocation
@@ -618,13 +634,10 @@ bfd_perform_relocation (bfd *abfd,
/* PR 17512: file: 0f67f69d. */
if (howto == NULL)
return bfd_reloc_undefined;
-
- /* Is the address of the relocation really within the section?
- Include the size of the reloc in the test for out of range addresses.
- PR 17512: file: c146ab8b, 46dff27f, 38e53ebf. */
+
+ /* Is the address of the relocation really within the section? */
octets = reloc_entry->address * bfd_octets_per_byte (abfd);
- if (octets + bfd_get_reloc_size (howto)
- > bfd_get_section_limit_octets (abfd, input_section))
+ if (!reloc_offset_in_range (howto, abfd, input_section, octets))
return bfd_reloc_outofrange;
/* Work out which section the relocation is targeted at and the
@@ -1012,8 +1025,7 @@ bfd_install_relocation (bfd *abfd,
/* Is the address of the relocation really within the section? */
octets = reloc_entry->address * bfd_octets_per_byte (abfd);
- if (octets + bfd_get_reloc_size (howto)
- > bfd_get_section_limit_octets (abfd, input_section))
+ if (!reloc_offset_in_range (howto, abfd, input_section, octets))
return bfd_reloc_outofrange;
/* Work out which section the relocation is targeted at and the
@@ -1351,8 +1363,7 @@ _bfd_final_link_relocate (reloc_howto_ty
bfd_size_type octets = address * bfd_octets_per_byte (input_bfd);
/* Sanity check the address. */
- if (octets + bfd_get_reloc_size (howto)
- > bfd_get_section_limit_octets (input_bfd, input_section))
+ if (!reloc_offset_in_range (howto, input_bfd, input_section, octets))
return bfd_reloc_outofrange;
/* This function assumes that we are dealing with a basic relocation
Index: git/bfd/ChangeLog
===================================================================
--- git.orig/bfd/ChangeLog
+++ git/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2017-04-29 Alan Modra <amodra@gmail.com>
+
+ PR 21432
+ * reloc.c (reloc_offset_in_range): New function.
+ (bfd_perform_relocation, bfd_install_relocation): Use it.
+ (_bfd_final_link_relocate): Likewise.
+
2017-04-26 Nick Clifton <nickc@redhat.com>
PR binutils/21431
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