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While fuzzing yabasic 2.86.2 with Honggfuzz, I found a heap-based buffer overflow in the myformat() function, in function.c.
Attaching a reproducer (gzipped so GitHub accepts it): test02.yab.gz
Issue can be reproduced by running:
yabasic test02.yab
=================================================================
==20807==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x626000002814 at pc 0x00000043cce7 bp 0x7ffe28e0e900 sp 0x7ffe28e0e098
WRITE of size 41236 at 0x626000002814 thread T0
#0 0x43cce6 in vsprintf (/home/fcambus/yabasic-2.86.2/yabasic+0x43cce6)
#1 0x43dc73 in sprintf (/home/fcambus/yabasic-2.86.2/yabasic+0x43dc73)
#2 0x4e4ad3 in myformat /home/fcambus/yabasic-2.86.2/function.c:1254:9
#3 0x4ded27 in function /home/fcambus/yabasic-2.86.2/function.c:465:14
#4 0x4d5717 in run_it /home/fcambus/yabasic-2.86.2/main.c:1779:17
#5 0x4c5fe8 in main /home/fcambus/yabasic-2.86.2/main.c:325:9
#6 0x7f664ab9b1e2 in __libc_start_main /build/glibc-4WA41p/glibc-2.30/csu/../csu/libc-start.c:308:16
#7 0x41da2d in _start (/home/fcambus/yabasic-2.86.2/yabasic+0x41da2d)
0x626000002814 is located 0 bytes to the right of 10004-byte region [0x626000000100,0x626000002814)
allocated by thread T0 here:
#0 0x49592d in malloc (/home/fcambus/yabasic-2.86.2/yabasic+0x49592d)
#1 0x4c6314 in my_malloc /home/fcambus/yabasic-2.86.2/main.c:2099:12
#2 0x4c5012 in main /home/fcambus/yabasic-2.86.2/main.c:122:23
#3 0x7f664ab9b1e2 in __libc_start_main /build/glibc-4WA41p/glibc-2.30/csu/../csu/libc-start.c:308:16
SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/fcambus/yabasic-2.86.2/yabasic+0x43cce6) in vsprintf
Shadow bytes around the buggy address:
0x0c4c7fff84b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4c7fff84c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4c7fff84d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4c7fff84e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4c7fff84f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c4c7fff8500: 00 00[04]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4c7fff8510: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4c7fff8520: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4c7fff8530: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4c7fff8540: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4c7fff8550: 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
Shadow gap: cc
==20807==ABORTING
The text was updated successfully, but these errors were encountered:
Hi,
While fuzzing yabasic 2.86.2 with Honggfuzz, I found a heap-based buffer overflow in the myformat() function, in function.c.
Attaching a reproducer (gzipped so GitHub accepts it): test02.yab.gz
Issue can be reproduced by running:
The text was updated successfully, but these errors were encountered: