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[binutils-gdb] PR19323 memory allocation greater than 4G
- From: Alan Modra <amodra at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 7 Dec 2015 03:21:03 -0000
- Subject: [binutils-gdb] PR19323 memory allocation greater than 4G
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=c20f6f63eda61348326a861a155716b8d9073307
commit c20f6f63eda61348326a861a155716b8d9073307
Author: Alan Modra <amodra@gmail.com>
Date: Mon Dec 7 13:41:36 2015 +1030
PR19323 memory allocation greater than 4G
On 32-bit targets, memory requested for program/section headers on a
fuzzed binary can wrap to 0. A bfd_alloc of zero bytes actually
returns a one byte allocation rather than a NULL pointer. This then
leads to buffer overflows.
Making this check unconditional triggers an extremely annoying gcc-5
warning.
PR19323
* elfcode.h (elf_object_p): Check for ridiculous e_shnum and
e_phnum values.
Diff:
---
bfd/ChangeLog | 6 ++++++
bfd/elfcode.h | 10 +++++++++-
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 0a92044..710b790 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,11 @@
2015-12-07 Alan Modra <amodra@gmail.com>
+ PR19323
+ * elfcode.h (elf_object_p): Check for ridiculous e_shnum and
+ e_phnum values.
+
+2015-12-07 Alan Modra <amodra@gmail.com>
+
* reloc.c (BFD_RELOC_PPC64_ENTRY): New.
* elf64-ppc.c (reloc_howto_type ppc64_elf_howto_raw): Add
entry for R_PPC64_ENTRY.
diff --git a/bfd/elfcode.h b/bfd/elfcode.h
index 26af1d1..915c8d5 100644
--- a/bfd/elfcode.h
+++ b/bfd/elfcode.h
@@ -676,6 +676,10 @@ elf_object_p (bfd *abfd)
Elf_Internal_Shdr *shdrp;
unsigned int num_sec;
+#ifndef BFD64
+ if (i_ehdrp->e_shnum > ((bfd_size_type) -1) / sizeof (*i_shdrp))
+ goto got_wrong_format_error;
+#endif
amt = sizeof (*i_shdrp) * i_ehdrp->e_shnum;
i_shdrp = (Elf_Internal_Shdr *) bfd_alloc (abfd, amt);
if (!i_shdrp)
@@ -766,7 +770,11 @@ elf_object_p (bfd *abfd)
Elf_Internal_Phdr *i_phdr;
unsigned int i;
- amt = i_ehdrp->e_phnum * sizeof (Elf_Internal_Phdr);
+#ifndef BFD64
+ if (i_ehdrp->e_phnum > ((bfd_size_type) -1) / sizeof (*i_phdr))
+ goto got_wrong_format_error;
+#endif
+ amt = i_ehdrp->e_phnum * sizeof (*i_phdr);
elf_tdata (abfd)->phdr = (Elf_Internal_Phdr *) bfd_alloc (abfd, amt);
if (elf_tdata (abfd)->phdr == NULL)
goto got_no_match;