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[RFC] binutils/objdump: Fix disassemble with huge elf sections
- From: Ravi Bangoria <ravi dot bangoria at linux dot vnet dot ibm dot com>
- To: binutils at sourceware dot org
- Cc: Ravi Bangoria <ravi dot bangoria at linux dot vnet dot ibm dot com>
- Date: Wed, 12 Jul 2017 11:00:20 +0530
- Subject: [RFC] binutils/objdump: Fix disassemble with huge elf sections
- Authentication-results: sourceware.org; auth=none
When elf section size is beyond unsigned int max value, objdump fails
to disassemble from that section. Ex on PowerPC,
$ objdump -h /proc/kcore
Idx Name Size VMA
4 load2 100000000 c000000000000000
Here, size of load2 section is 0x100000000. Also note that, 0xc00....
address range is kernel space for PowerPC. Now let's try to disassemble
do_sys_open() using /proc/kcore.
$ cat /proc/kallsyms | grep -A1 -w do_sys_open
c00000000036c000 T do_sys_open
c00000000036c2d0 T SyS_open
Before patch:
$ objdump -d --start-address=0xc00000000036c000 --stop-address=0xc00000000036c2d0 /proc/kcore
/proc/kcore: file format elf64-powerpcle
Disassembly of section load2:
c00000000036c000 <load2+0x36c000>:
c00000000036c000: Address 0xc00000000036c000 is out of bounds.
Fix this by changing type of 'buffer_length' from unsigned int to
size_t. After patch:
$ objdump -d --start-address=0xc00000000036c000 --stop-address=0xc00000000036c2d0 /proc/kcore
/proc/kcore: file format elf64-powerpcle
Disassembly of section load2:
c00000000036c000 <load2+0x36c000>:
c00000000036c000: fc 00 4c 3c addis r2,r12,252
c00000000036c004: 00 53 42 38 addi r2,r2,21248
c00000000036c008: a6 02 08 7c mflr r0
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
include/dis-asm.h | 2 +-
opcodes/dis-buf.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/dis-asm.h b/include/dis-asm.h
index 9b42514..4ff8bc9 100644
--- a/include/dis-asm.h
+++ b/include/dis-asm.h
@@ -158,7 +158,7 @@ typedef struct disassemble_info
/* These are for buffer_read_memory. */
bfd_byte *buffer;
bfd_vma buffer_vma;
- unsigned int buffer_length;
+ size_t buffer_length;
/* This variable may be set by the instruction decoder. It suggests
the number of bytes objdump should display on a single line. If
diff --git a/opcodes/dis-buf.c b/opcodes/dis-buf.c
index 061bc44..2027f08 100644
--- a/opcodes/dis-buf.c
+++ b/opcodes/dis-buf.c
@@ -31,10 +31,10 @@ buffer_read_memory (bfd_vma memaddr,
unsigned int length,
struct disassemble_info *info)
{
- unsigned int opb = info->octets_per_byte;
- unsigned int end_addr_offset = length / opb;
- unsigned int max_addr_offset = info->buffer_length / opb;
- unsigned int octets = (memaddr - info->buffer_vma) * opb;
+ unsigned long opb = info->octets_per_byte;
+ unsigned long end_addr_offset = length / opb;
+ unsigned long max_addr_offset = info->buffer_length / opb;
+ unsigned long octets = (memaddr - info->buffer_vma) * opb;
if (memaddr < info->buffer_vma
|| memaddr - info->buffer_vma > max_addr_offset
--
2.9.4