heap-buffer-overflow at Jsi_DSAppendLen src/jsiDString.c:109

[kvenux]

Build environment:

Ubuntu 16.04
gcc 5.4.0
version: 73f457f
build command:
export JSI__SANITIZE=1
make
test command: ./jsish poc

POC

jsish-1024-000133.txt

Description

Below is the ASAN outputs.

==42992==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60b00000a4f2 at pc 0x7fe14fca0935 bp 0x7ffe63bb9fa0 sp 0x7ffe63bb9748
READ of size 96 at 0x60b00000a4f2 thread T0
#0 0x7fe14fca0934 in __asan_memcpy (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x8c934)
#1 0x5c12d1 in memcpy /usr/include/x86_64-linux-gnu/bits/string3.h:53
#2 0x5c12d1 in Jsi_DSAppendLen src/jsiDString.c:109
#3 0x5ebb2e in Jsi_UtfSubstr src/jsiUtf8.c:130
#4 0x4e74f9 in _StringTrimCmd src/jsiString.c:370
#5 0x4e74f9 in StringTrimCmd src/jsiString.c:378
#6 0x4c405d in jsi_FuncCallSub src/jsiProto.c:244
#7 0x73eaa4 in jsiFunctionSubCall src/jsiEval.c:790
#8 0x73eaa4 in jsiEvalFunction src/jsiEval.c:825
#9 0x73eaa4 in jsiEvalCodeSub src/jsiEval.c:1250
#10 0x7506ec in jsi_evalcode src/jsiEval.c:2190
#11 0x4c517a in jsi_FuncCallSub src/jsiProto.c:220
#12 0x73e7ca in jsiFunctionSubCall src/jsiEval.c:790
#13 0x73e7ca in jsiEvalFunction src/jsiEval.c:825
#14 0x73e7ca in jsiEvalCodeSub src/jsiEval.c:1250
#15 0x7506ec in jsi_evalcode src/jsiEval.c:2190
#16 0x75317f in jsi_evalStrFile src/jsiEval.c:2496
#17 0x499c46 in Jsi_Main src/jsiInterp.c:917
#18 0xc0345a in jsi_main src/main.c:44
#19 0x7fe14f14083f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
#20 0x434f48 in _start (/home/keven/Fuzzing/jsish-1024/jsish+0x434f48)

0x60b00000a4f2 is located 0 bytes to the right of 98-byte region [0x60b00000a490,0x60b00000a4f2)
allocated by thread T0 here:
#0 0x7fe14fcac602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
#1 0x49e422 in Jsi_Malloc src/jsiUtils.c:52

SUMMARY: AddressSanitizer: heap-buffer-overflow ??:0 __asan_memcpy
Shadow bytes around the buggy address:
0x0c167fff9440: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c167fff9450: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c167fff9460: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c167fff9470: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c167fff9480: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c167fff9490: fa fa 00 00 00 00 00 00 00 00 00 00 00 00[02]fa
0x0c167fff94a0: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
0x0c167fff94b0: fd fd fd fd fd fa fa fa fa fa fa fa fa fa fd fd
0x0c167fff94c0: fd fd fd fd fd fd fd fd fd fd fd fd fa fa fa fa
0x0c167fff94d0: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fd fd
0x0c167fff94e0: fd fd fa fa fa fa fa fa fa fa 00 00 00 00 00 00
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
==42992==ABORTING

[pcmacdon]

trim() was trying to live in the UTF world, l but that doesn't really make sense, as the implementation is non-standard.