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From 95a6d23566165208853a68d9cd3c6eedca840ec6 Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Tue, 8 May 2018 12:51:06 +0100
Subject: [PATCH] Prevent a memory exhaustion failure when running objdump on a
fuzzed input file with corrupt string and attribute sections.
PR 22809
* elf.c (bfd_elf_get_str_section): Check for an excessively large
string section.
* elf-attrs.c (_bfd_elf_parse_attributes): Issue an error if the
attribute section is larger than the size of the file.
---
bfd/ChangeLog | 8 ++++++++
bfd/elf-attrs.c | 9 +++++++++
bfd/elf.c | 1 +
3 files changed, 18 insertions(+)
diff --git a/bfd/elf-attrs.c b/bfd/elf-attrs.c
index dfdf1a5..b353309 100644
--- a/bfd/elf-attrs.c
+++ b/bfd/elf-attrs.c
@@ -438,6 +438,15 @@ _bfd_elf_parse_attributes (bfd *abfd, Elf_Internal_Shdr * hdr)
/* PR 17512: file: 2844a11d. */
if (hdr->sh_size == 0)
return;
+ if (hdr->sh_size > bfd_get_file_size (abfd))
+ {
+ /* xgettext:c-format */
+ _bfd_error_handler (_("%pB: error: attribute section '%pA' too big: %#llx"),
+ abfd, hdr->bfd_section, (long long) hdr->sh_size);
+ bfd_set_error (bfd_error_invalid_operation);
+ return;
+ }
+
contents = (bfd_byte *) bfd_malloc (hdr->sh_size + 1);
if (!contents)
return;
diff --git a/bfd/elf.c b/bfd/elf.c
index 21bc4e7..3e8d510 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -298,6 +298,7 @@ bfd_elf_get_str_section (bfd *abfd, unsigned int shindex)
/* Allocate and clear an extra byte at the end, to prevent crashes
in case the string table is not terminated. */
if (shstrtabsize + 1 <= 1
+ || shstrtabsize > bfd_get_file_size (abfd)
|| bfd_seek (abfd, offset, SEEK_SET) != 0
|| (shstrtab = (bfd_byte *) bfd_alloc (abfd, shstrtabsize + 1)) == NULL)
shstrtab = NULL;
--
2.9.3
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