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Message-ID: <1843.42902818457-sendEmail@localhost>
Date: Mon, 10 Apr 2017 07:38:26 +0000
From: "Agostino Sarubbo" <ago@...too.org>
To: "oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com>
Subject: elfutils: heap-based buffer overflow in check_symtab_shndx (elflint.c)
Description:
elfutils is a set of libraries/utilities to handle ELF objects (drop in replacement for libelf).
A fuzz on eu-elflint showed an heap overflow.
The complete ASan output:
# eu-elflint -d $FILE
==14342==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000efd0 at pc 0x0000004267ec bp 0x7ffdf36a7ad0 sp 0x7ffdf36a7ac8
READ of size 4 at 0x60200000efd0 thread T0
#0 0x4267eb in check_symtab_shndx /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:1961
#1 0x4267eb in check_sections /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:4114
#2 0x42961f in process_elf_file /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:4697
#3 0x42961f in process_file /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:242
#4 0x402d33 in main /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:175
#5 0x7f625ef4678f in __libc_start_main (/lib64/libc.so.6+0x2078f)
#6 0x403498 in _start (/usr/bin/eu-elflint+0x403498)
0x60200000efd2 is located 0 bytes to the right of 2-byte region [0x60200000efd0,0x60200000efd2)
allocated by thread T0 here:
#0 0x7f6260633288 in malloc (/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/libasan.so.3+0xc2288)
#1 0x7f626028fb46 in convert_data /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/elf_getdata.c:166
#2 0x7f626028fb46 in __libelf_set_data_list_rdlock /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/elf_getdata.c:434
#3 0x7f6260290662 in __elf_getdata_rdlock /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/elf_getdata.c:541
#4 0x7f6260290776 in elf_getdata /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/elf_getdata.c:559
#5 0x7f62602bc035 in elf32_getchdr /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/elf32_getchdr.c:72
#6 0x7f62602bc55c in gelf_getchdr /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/libelf/gelf_getchdr.c:52
#7 0x420edf in check_sections /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:3911
#8 0x42961f in process_elf_file /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:4697
#9 0x42961f in process_file /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:242
#10 0x402d33 in main /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:175
#11 0x7f625ef4678f in __libc_start_main (/lib64/libc.so.6+0x2078f)
SUMMARY: AddressSanitizer: heap-buffer-overflow /tmp/portage/dev-libs/elfutils-0.168/work/elfutils-0.168/src/elflint.c:1961 in check_symtab_shndx
Shadow bytes around the buggy address:
0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c047fff9df0: fa fa fa fa fa fa fa fa fa fa[02]fa fa fa 00 01
0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==14342==ABORTING
Affected version:
0.168
Fixed version:
0.169 (not released atm)
Commit fix:
https://sourceware.org/ml/elfutils-devel/2017-q1/msg00129.html
Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.
CVE:
CVE-2017-7611
Reproducer:
https://github.com/asarubbo/poc/blob/master/00234-elfutils-heapoverflow-check_symtab_shndx
Timeline:
2017-03-27: bug discovered and reported to upstream
2017-04-04: blog post about the issue
2017-04-09: CVE assigned
Note:
This bug was found with American Fuzzy Lop.
Permalink:
https://blogs.gentoo.org/ago/2017/04/03/elfutils-heap-based-buffer-overflow-in-check_symtab_shndx-elflint-c
--
Agostino Sarubbo
Gentoo Linux Developer
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