Created attachment 3773 [details]
poc

## IMG_LoadPCX_RW@IMG_pcx.c:178-24___heap-buffer-overflow

### description

    An issue was discovered in libsdl2 2.0.9 with SDL2_image-2.0.4, There is a heap-buffer-overflow in function IMG_LoadPCX_RW at IMG_pcx.c:178-24

### commandline

    loadtif  @@ 

### source

```c
 174                         }
 175                     } else
 176                         count = 1;
 177                 }
> 178                 dst[i] = ch;
 179                 count--;
 180             }
 181         }
 182 
 183         if(src_bits <= 4) {

// loadtif.c
// #include <stdio.h>
// #include <SDL.h>
// #include <SDL_image.h>
//
// int main(int argc, char * argv[]){
//         IMG_Init(IMG_INIT_TIF);//IMG_INIT_JPG);IMG_INIT_PNG
//         while(__AFL_LOOP(1000)){
//               SDL_Surface * image = IMG_Load(argv[1]);
//               if (image){
//                 SDL_FreeSurface(image);
//               }
//         }
//         IMG_Quit();
// }
```

### bug report

```txt
=================================================================
==13979==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000eff4 at pc 0x7fcdecb76a15 bp 0x7ffddb89ab30 sp 0x7ffddb89ab28
WRITE of size 1 at 0x60200000eff4 thread T0
    #0 0x7fcdecb76a14 in IMG_LoadPCX_RW /src/SDL2_image-2.0.4/IMG_pcx.c:178:24
    #1 0x7fcdecb639bd in IMG_LoadTyped_RW /src/SDL2_image-2.0.4/IMG.c:195:17
    #2 0x7fcdecb62f41 in IMG_Load /src/SDL2_image-2.0.4/IMG.c:136:12
    #3 0x4ea0f0 in main /src/loadtif.c:8:37
    #4 0x7fcdeb66982f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #5 0x4189e8 in _start (/src/aflbuild/installed/bin/loadtif+0x4189e8)

0x60200000eff4 is located 0 bytes to the right of 4-byte region [0x60200000eff0,0x60200000eff4)
allocated by thread T0 here:
    #0 0x4b8b18 in malloc (/src/aflbuild/installed/bin/loadtif+0x4b8b18)
    #1 0x7fcdec6de868 in SDL_malloc_REAL /src/libsdl2/src/stdlib/SDL_malloc.c:5328:11

SUMMARY: AddressSanitizer: heap-buffer-overflow /src/SDL2_image-2.0.4/IMG_pcx.c:178:24 in IMG_LoadPCX_RW
Shadow bytes around the buggy address:
  0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c047fff9df0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa[04]fa
  0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff9e40: 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
  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
==13979==ABORTING

```

### others

    from fuzz project pwd-libsdl2-loadtif-00
    crash name pwd-libsdl2-loadtif-00-00000000-20190418.tif
    Auto-generated by pyspider at 2019-04-19 00:07:03