After some fuzz testing I found a crashing test case.
Changeset: 15166:e8048eade0e6
Command: gm convert -negate -clip gm_hoobr_ReadRLEImage /dev/null
ASAN:
==7513==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x616000000ee0 at pc 0x00000089f47e bp 0x7fff3ebe1db0 sp 0x7fff3ebe1da8
READ of size 1 at 0x616000000ee0 thread T0
#0 0x89f47d in ReadRLEImage XYZ/GM/coders/rle.c:753:25
#1 0x595069 in ReadImage XYZ/GM/magick/constitute.c:1607:13
#2 0x51a1e0 in ConvertImageCommand XYZ/GM/magick/command.c:4348:22
#3 0x52fd21 in MagickCommand XYZ/GM/magick/command.c:8869:17
#4 0x567983 in GMCommandSingle XYZ/GM/magick/command.c:17396:10
#5 0x566683 in GMCommand XYZ/GM/magick/command.c:17449:16
#6 0x7fdb5a87b82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#7 0x41beb8 in _start (/usr/local/bin/gm+0x41beb8)
0x616000000ee0 is located 0 bytes to the right of 608-byte region [0x616000000c80,0x616000000ee0)
allocated by thread T0 here:
#0 0x4c2bbc in __interceptor_malloc /scratch/llvm/clang-4/xenial/final/llvm.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:66:3
#1 0x61e7d6 in MagickMalloc XYZ/GM/magick/memory.c:156:10
#2 0x61e7d6 in MagickMallocArray XYZ/GM/magick/memory.c:347
#3 0x595069 in ReadImage XYZ/GM/magick/constitute.c:1607:13
#4 0x51a1e0 in ConvertImageCommand XYZ/GM/magick/command.c:4348:22
#5 0x52fd21 in MagickCommand XYZ/GM/magick/command.c:8869:17
#6 0x567983 in GMCommandSingle XYZ/GM/magick/command.c:17396:10
#7 0x566683 in GMCommand XYZ/GM/magick/command.c:17449:16
#8 0x7fdb5a87b82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
SUMMARY: AddressSanitizer: heap-buffer-overflow XYZ/GM/coders/rle.c:753:25 in ReadRLEImage
Shadow bytes around the buggy address:
0x0c2c7fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2c7fff8190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2c7fff81a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2c7fff81b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2c7fff81c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c2c7fff81d0: 00 00 00 00 00 00 00 00 00 00 00 00[fa]fa fa fa
0x0c2c7fff81e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2c7fff81f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2c7fff8200: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2c7fff8210: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2c7fff8220: 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
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
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
==7513==ABORTING
This problem is fixed by Mercurial changeset 15177:5381c71724e3. Thanks for the report!