A heap-based buffer overflow issue was found in ImageMagick's PushCharPixel() function in quantum-private.h. This issue may allow a local attacker to trick the user into opening a specially crafted file, triggering an out-of-bounds read error and allowing an application to crash, resulting in a denial of service.
### Prerequisites

- [x] I have written a descriptive issue title
- [x] I have verified that I am using the latest version of ImageMagick
- [x] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There is a vlun heap overflow found in " /MagickCore/quantum-private.h:236:11 in PushCharPixel"

### Steps to Reproduce
<!-- List of steps, sample code, failing test or link to a project that reproduces the behavior.
     Make sure you place a stack trace inside a code (```) block to avoid linking unrelated issues -->
[crashed file](https://github.com/p1ay8y3ar/crashdatas/blob/master/imageMagic/7.0.9-27/id%5E%25000000%2Csig%5E%2506%2Csrc%5E%25000000%2Cop%5E%25flip1%2Cpos%5E%25191020)

```shell
./magic convert xxx.tiff xxx.png
```

ASAN's full log can be found in  [here](https://github.com/p1ay8y3ar/crashdatas/blob/master/imageMagic/7.0.9-27/heap-buffer-overflow) 

port of ASAN's log 
```c
==74648==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f62ea369962 at pc 0x000001389ad0 bp 0x7ffc161d7be0 sp 0x7ffc161d7bd8
READ of size 1 at 0x7f62ea369962 thread T0
    #0 0x1389acf in PushCharPixel /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/./MagickCore/quantum-private.h:236:11
    #1 0x1389acf in ImportRGBQuantum /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/quantum-import.c:3797:11
    #2 0x1389acf in ImportQuantumPixels /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/quantum-import.c:4776:7
    #3 0xd1eb2d in ReadTIFFImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/coders/tiff.c:1970:20
    #4 0xe84e2d in ReadImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:553:15
    #5 0xe89948 in ReadImages /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:941:9
    #6 0x1731cb8 in ConvertImageCommand /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/convert.c:606:18
    #7 0x1897ac3 in MagickCommandGenesis /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/mogrify.c:186:14
    #8 0x4cf918 in MagickMain /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:149:10
    #9 0x4cf918 in main /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:180:10
    #10 0x7f62f00671e2 in __libc_start_main /build/glibc-t7JzpG/glibc-2.30/csu/../csu/libc-start.c:308:16
    #11 0x4279ed in _start (/home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick+0x4279ed)

0x7f62ea369962 is located 0 bytes to the right of 225634-byte region [0x7f62ea332800,0x7f62ea369962)
allocated by thread T0 here:
    #0 0x49f8ed in malloc (/home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick+0x49f8ed)
    #1 0xd1e7ac in ReadTIFFImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/coders/tiff.c:1922:40
    #2 0xe84e2d in ReadImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:553:15
    #3 0xe89948 in ReadImages /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:941:9
    #4 0x1731cb8 in ConvertImageCommand /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/convert.c:606:18
    #5 0x1897ac3 in MagickCommandGenesis /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/mogrify.c:186:14
    #6 0x4cf918 in MagickMain /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:149:10
    #7 0x4cf918 in main /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:180:10
    #8 0x7f62f00671e2 in __libc_start_main /build/glibc-t7JzpG/glibc-2.30/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/./MagickCore/quantum-private.h:236:11 in PushCharPixel
```


### System Configuration
<!-- Tell us about the environment where you are experiencing the bug -->

- ImageMagick version:

``` c
Version: ImageMagick 7.0.9-27 Q16 x86_64 2020-03-01 https://imagemagick.org
Copyright: © 1999-2020 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC HDRI OpenMP(3.1) 
Delegates (built-in): fontconfig freetype heic jbig jng jp2 jpeg lzma png tiff webp x xml zlib
```

- Environment (Operating system, version and so on):
```shell
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=19.10
DISTRIB_CODENAME=eoan
DISTRIB_DESCRIPTION="Ubuntu 19.10
```
- Additional information:

<!-- Thanks for reporting the issue to ImageMagick! -->

heap-buffer-overflow in /MagickCore/quantum-private.h
This is a GitHub Issue
repo:ImageMagick
owner:ImageMagick
Title : heap-buffer-overflow in /MagickCore/quantum-private.h
Issue date:

--- start body ---
### Prerequisites

- [x] I have written a descriptive issue title
- [x] I have verified that I am using the latest version of ImageMagick
- [x] I have searched [open](https://github.com/ImageMagick/ImageMagick/issues) and [closed](https://github.com/ImageMagick/ImageMagick/issues?q=is%3Aissue+is%3Aclosed) issues to ensure it has not already been reported

### Description
<!-- A description of the bug or feature -->
There is a vlun heap overflow found in " /MagickCore/quantum-private.h:236:11 in PushCharPixel"

### Steps to Reproduce
<!-- List of steps, sample code, failing test or link to a project that reproduces the behavior.
     Make sure you place a stack trace inside a code (```) block to avoid linking unrelated issues -->
[crashed file](https://github.com/p1ay8y3ar/crashdatas/blob/master/imageMagic/7.0.9-27/id%5E%25000000%2Csig%5E%2506%2Csrc%5E%25000000%2Cop%5E%25flip1%2Cpos%5E%25191020)

```shell
./magic convert xxx.tiff xxx.png
```

ASAN's full log can be found in  [here](https://github.com/p1ay8y3ar/crashdatas/blob/master/imageMagic/7.0.9-27/heap-buffer-overflow) 

port of ASAN's log 
```c
==74648==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f62ea369962 at pc 0x000001389ad0 bp 0x7ffc161d7be0 sp 0x7ffc161d7bd8
READ of size 1 at 0x7f62ea369962 thread T0
    #0 0x1389acf in PushCharPixel /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/./MagickCore/quantum-private.h:236:11
    #1 0x1389acf in ImportRGBQuantum /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/quantum-import.c:3797:11
    #2 0x1389acf in ImportQuantumPixels /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/quantum-import.c:4776:7
    #3 0xd1eb2d in ReadTIFFImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/coders/tiff.c:1970:20
    #4 0xe84e2d in ReadImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:553:15
    #5 0xe89948 in ReadImages /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:941:9
    #6 0x1731cb8 in ConvertImageCommand /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/convert.c:606:18
    #7 0x1897ac3 in MagickCommandGenesis /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/mogrify.c:186:14
    #8 0x4cf918 in MagickMain /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:149:10
    #9 0x4cf918 in main /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:180:10
    #10 0x7f62f00671e2 in __libc_start_main /build/glibc-t7JzpG/glibc-2.30/csu/../csu/libc-start.c:308:16
    #11 0x4279ed in _start (/home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick+0x4279ed)

0x7f62ea369962 is located 0 bytes to the right of 225634-byte region [0x7f62ea332800,0x7f62ea369962)
allocated by thread T0 here:
    #0 0x49f8ed in malloc (/home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick+0x49f8ed)
    #1 0xd1e7ac in ReadTIFFImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/coders/tiff.c:1922:40
    #2 0xe84e2d in ReadImage /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:553:15
    #3 0xe89948 in ReadImages /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickCore/constitute.c:941:9
    #4 0x1731cb8 in ConvertImageCommand /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/convert.c:606:18
    #5 0x1897ac3 in MagickCommandGenesis /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/MagickWand/mogrify.c:186:14
    #6 0x4cf918 in MagickMain /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:149:10
    #7 0x4cf918 in main /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/utilities/magick.c:180:10
    #8 0x7f62f00671e2 in __libc_start_main /build/glibc-t7JzpG/glibc-2.30/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/freedom/Desktop/fuzz_sourcecode/imageMagick/test/ImageMagick-7.0.9-27/./MagickCore/quantum-private.h:236:11 in PushCharPixel
```


### System Configuration
<!-- Tell us about the environment where you are experiencing the bug -->

- ImageMagick version:

``` c
Version: ImageMagick 7.0.9-27 Q16 x86_64 2020-03-01 https://imagemagick.org
Copyright: © 1999-2020 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC HDRI OpenMP(3.1) 
Delegates (built-in): fontconfig freetype heic jbig jng jp2 jpeg lzma png tiff webp x xml zlib
```

- Environment (Operating system, version and so on):
```shell
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=19.10
DISTRIB_CODENAME=eoan
DISTRIB_DESCRIPTION="Ubuntu 19.10
```
- Additional information:

<!-- Thanks for reporting the issue to ImageMagick! -->

--- end body ---
