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Date: Sat, 25 Feb 2017 11:36:05 +0000
From: "Agostino Sarubbo" <ago@...too.org>
To: "oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com>
Subject: gnu-paxutils: multiple crashes

Description:
GNU paxutils is a suite of archive utilities: it will provide cpio, tar and POSIX pax archivers.

A fuzzing on tar and pax shows multiple crashes.
I really don’t know if atm those tools are used somewhere.

Details:

# tar -t -f $FILE
buffer.c:1480:40: runtime error: index 7168 out of bounds for type 'char [512]'
SUMMARY: AddressSanitizer: undefined-behavior buffer.c:1480:40 in 
/bins/tar: Record size of archive appears to be 14 blocks (20 expected)
/bins/tar: Hmm, this doesn't look like a tar archive
/bins/tar: Skipping to next file header

reading.c:327:19: runtime error: member access within null pointer of type 'union block'
SUMMARY: AddressSanitizer: undefined-behavior reading.c:327:19 in 
reading.c:327:19: runtime error: member access within null pointer of type 'struct sparse_header'
SUMMARY: AddressSanitizer: undefined-behavior reading.c:327:19 in 

ASAN:DEADLYSIGNAL
=================================================================
==9542==ERROR: AddressSanitizer: SEGV on unknown address 0x0000000001f8 (pc 0x000000570b4a bp 0x7ffd7ab13eb0 sp 0x7ffd7ab13e90 T0)
==9542==The signal is caused by a READ memory access.
==9542==Hint: address points to the zero page.
    #0 0x570b49 in skip_extended_headers /root/paxutils-2.4h/src/reading.c:327:33
    #1 0x55721d in list_archive /root/paxutils-2.4h/src/list.c:120:7
    #2 0x5718ef in read_and /root/paxutils-2.4h/src/reading.c:406:5
    #3 0x57c746 in main /root/paxutils-2.4h/src/./tar.c:1508:7
    #4 0x7f5c524fc78f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #5 0x41a498 in _start (/root/bins/tar+0x41a498)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /root/paxutils-2.4h/src/reading.c:327:33 in skip_extended_headers
==9542==ABORTING

Reproducer:
https://github.com/asarubbo/poc/blob/master/00178-gnupaxutils-tar-segv

Obviously, the runtime error “member access within null pointer…” is the ubsan’s way to print what asan subsequently said as SEGV, so it is the same issue.

# pax -f $FILE
==10938==ERROR: AddressSanitizer: global-buffer-overflow on address 0x00000141615f at pc 0x00000052853e bp 0x7ffed94bdc30 sp 0x7ffed94bdc28
READ of size 1 at 0x00000141615f thread T0
    #0 0x52853d in read_in_tar_header /root/paxutils-2.4h/src/fmttar.c:363:8
    #1 0x50dd65 in read_in_header /root/paxutils-2.4h/src/copyin.c:99:7
    #2 0x50f675 in process_copy_in /root/paxutils-2.4h/src/copyin.c:236:7
    #3 0x50d164 in main /root/paxutils-2.4h/src/./pax.c:485:3
    #4 0x7fd70e06478f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #5 0x41a448 in _start (/usr/bin/pax+0x41a448)

Reproducer:
https://github.com/asarubbo/poc/blob/master/00179-gnupaxutils-pax-globaloverflow

# pax -f $FILE
==21061==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000efb9 at pc 0x00000048041a bp 0x7ffea3351e10 sp 0x7ffea33515c0
READ of size 10 at 0x60200000efb9 thread T0
    #0 0x480419 in __interceptor_strcmp 
/tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:284
    #1 0x50f969 in process_copy_in /root/paxutils-2.4h/src/copyin.c:261:11
    #2 0x50d164 in main /root/paxutils-2.4h/src/./pax.c:485:3
    #3 0x7fe2d680178f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #4 0x41a448 in _start (/usr/bin/pax+0x41a448)

Reproducer:
https://github.com/asarubbo/poc/blob/master/00180-gnupaxutils-pax-heapoverflow

# pax -f $FILE
fmttar.c:450:11: runtime error: index 6 out of bounds for type 'char [6]'                                                                                                                      
SUMMARY: AddressSanitizer: undefined-behavior fmttar.c:450:11

==7159==ERROR: AddressSanitizer: memcpy-param-overlap: memory ranges [0x7fe6f8001420,0x7fe6f800161f) and [0x7fe6f8001421, 0x7fe6f8001620) overlap
    #0 0x4bc091 in __asan_memcpy /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_interceptors.cc:413
    #1 0x526da0 in read_in_tar_header /root/paxutils-2.4h/src/fmttar.c:265:4
    #2 0x50dd65 in read_in_header /root/paxutils-2.4h/src/copyin.c:99:7
    #3 0x50f675 in process_copy_in /root/paxutils-2.4h/src/copyin.c:236:7
    #4 0x50d164 in main /root/paxutils-2.4h/src/./pax.c:485:3
    #5 0x7fe6fae7178f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #6 0x41a448 in _start (/usr/bin/pax+0x41a448)

Reproducer:
https://github.com/asarubbo/poc/blob/master/00181-gnupaxutils-pax-memcpyparoverlap

# pax -f $FILE
==11514==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7f8b47900220 at pc 0x00000053bf25 bp 0x7ffd949d5cc0 sp 0x7ffd949d5cb8
READ of size 1 at 0x7f8b47900220 thread T0
    #0 0x53bf24 in otoa /root/paxutils-2.4h/lib/octal.c:33:10
    #1 0x5287f5 in is_tar_header /root/paxutils-2.4h/src/fmttar.c:427:3
    #2 0x50d8d4 in read_in_header /root/paxutils-2.4h/src/copyin.c:74:27
    #3 0x50f675 in process_copy_in /root/paxutils-2.4h/src/copyin.c:236:7
    #4 0x50d164 in main /root/paxutils-2.4h/src/./pax.c:485:3
    #5 0x7f8b4a75378f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #6 0x41a448 in _start (/usr/bin/pax+0x41a448)

Reproducer:
https://github.com/asarubbo/poc/blob/master/00182-gnupaxutils-pax-stackoverflow

Affected version:
2.4h

Fixed version:
N/A

Commit fix:
N/A

Credit:
These bugs were discovered by Agostino Sarubbo of Gentoo.

Timeline:
2017-02-17: bugs discovered
2017-02-21: bugs reported to upstream
2017-02-21: blog post about the issue

Note:
These bugs were found with American Fuzzy Lop.
The email to upstream was rejected.

Permalink:
https://blogs.gentoo.org/ago/2017/02/21/gnu-paxutils-multiple-crashes

--
Agostino Sarubbo
Gentoo Linux Developer


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