lrzip: use-after-free in read_stream (stream.c)

Description:
lrzip is a compression utility that excels at compressing large files.

The complete ASan output of the issue:

# lrzip -t $FILE
==4026==ERROR: AddressSanitizer: heap-use-after-free on address 0x62100000dd00 at pc 0x0000004bccc5 bp 0x7ffcf3b4d9f0 sp 0x7ffcf3b4d1a0
READ of size 1 at 0x62100000dd00 thread T0
    #0 0x4bccc4 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 0x53cff6 in read_stream /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1747:4
    #2 0x5307fc in read_vchars /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:79:6
    #3 0x5307fc in unzip_match /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:208
    #4 0x5307fc in runzip_chunk /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:329
    #5 0x5307fc in runzip_fd /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:382
    #6 0x519b41 in decompress_file /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/lrzip.c:826:6
    #7 0x511074 in main /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/main.c:669:4
    #8 0x7f743a5d278f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289
    #9 0x41abf8 in _init (/usr/bin/lrzip+0x41abf8)

0x62100000dd00 is located 0 bytes inside of 4096-byte region [0x62100000dd00,0x62100000ed00)
freed by thread T0 here:
    #0 0x4d3660 in free /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:47
    #1 0x53d186 in fill_buffer /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1574:3
    #2 0x53d186 in read_stream /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1755
    #3 0x5307fc in read_vchars /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:79:6
    #4 0x5307fc in unzip_match /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:208
    #5 0x5307fc in runzip_chunk /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:329
    #6 0x5307fc in runzip_fd /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:382
    #7 0x519b41 in decompress_file /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/lrzip.c:826:6
    #8 0x511074 in main /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/main.c:669:4
    #9 0x7f743a5d278f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289

previously allocated by thread T1 here:
    #0 0x4d39b8 in malloc /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:64
    #1 0x54b0d7 in lzma_decompress_buf /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:546:20
    #2 0x54b0d7 in ucompthread /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1522
    #3 0x7f743b36e4a3 in start_thread /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/nptl/pthread_create.c:333

Thread T1 created by T0 here:
    #0 0x42d49d in pthread_create /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_interceptors.cc:245
    #1 0x53e70f in create_pthread /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:133:6
    #2 0x53e70f in fill_buffer /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1673
    #3 0x53e70f in read_stream /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/stream.c:1755
    #4 0x5303e3 in read_u8 /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:55:6
    #5 0x5303e3 in read_header /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:144
    #6 0x5303e3 in runzip_chunk /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:314
    #7 0x5303e3 in runzip_fd /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/runzip.c:382
    #8 0x519b41 in decompress_file /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/lrzip.c:826:6
    #9 0x511074 in main /tmp/portage/app-arch/lrzip-0.631/work/lrzip-0.631/main.c:669:4
    #10 0x7f743a5d278f in __libc_start_main /tmp/portage/sys-libs/glibc-2.23-r3/work/glibc-2.23/csu/../csu/libc-start.c:289

SUMMARY: AddressSanitizer: heap-use-after-free /tmp/portage/sys-devel/llvm-3.9.1-r1/work/llvm-3.9.1.src/projects/compiler-rt/lib/asan/asan_interceptors.cc:413 in __asan_memcpy
Shadow bytes around the buggy address:
  0x0c427fff9b50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff9b60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff9b70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff9b80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff9b90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c427fff9ba0:[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c427fff9bb0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c427fff9bc0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c427fff9bd0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c427fff9be0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c427fff9bf0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
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
==4026==ABORTING

Affected version:
0.631

Fixed version:
N/A

Commit fix:
N/A

Credit:
This bug was discovered by Agostino Sarubbo of Gentoo.

CVE:
CVE-2017-8846

Reproducer:
https://github.com/asarubbo/poc/blob/master/00233-lrzip-UAF-read_stream

Timeline:
2017-03-24: bug discovered and reported to upstream
2017-05-07: blog post about the issue
2017-05-08: CVE assigned

Note:
This bug was found with American Fuzzy Lop.

Permalink:

lrzip: use-after-free in read_stream (stream.c)

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