Hi, I found a null pointer reference problem.
version: 0.4.8
command: swftophp poc
poc:
[decompile.c_642_11.tar.gz](https://github.com/libming/libming/files/7273121/decompile.c_642_11.tar.gz)

Here is the report from ASAN:
```
header indicates a filesize of 761 but filesize is 162
<?php
$m = new SWFMovie(1);

ming_setscale(1.0);
$m->setRate(128.000000);
$m->setDimension(-18499, 3460);

/* Note: xMin and/or yMin are not 0! */

$m->setFrames(771);

/* SWF_DOACTION */
ASAN:DEADLYSIGNAL
=================================================================
==68218==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7fc2cb4407c6 bp 0x7ffd3db3ca40 sp 0x7ffd3db3c1c8 T0)
==68218==The signal is caused by a READ memory access.
==68218==Hint: address points to the zero page.
    #0 0x7fc2cb4407c5 in strlen (/lib/x86_64-linux-gnu/libc.so.6+0x8b7c5)
    #1 0x43e89c in __interceptor_strlen.part.31 /home/radon/build/llvm_tools/llvm-4.0.0.src/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:282
    #2 0x54a3b2 in newVar_N /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:642:11
    #3 0x540218 in decompileCALLMETHOD /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:2843:9
    #4 0x52c507 in decompileAction /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3267:10
    #5 0x545f60 in decompileActions /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3401:6
    #6 0x544319 in decompileSETTARGET /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3076:3
    #7 0x52ce49 in decompileAction /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3372:10
    #8 0x545f60 in decompileActions /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3401:6
    #9 0x545b66 in decompile5Action /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3423:2
    #10 0x51f261 in outputSWF_DOACTION /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/outputscript.c:1548:29
    #11 0x51c3c9 in outputBlock /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/outputscript.c:2079:4
    #12 0x52855e in readMovie /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/main.c:277:4
    #13 0x526bbc in main /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/main.c:350:2
    #14 0x7fc2cb3d583f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
    #15 0x419ed8 in _start (/home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/swftophp+0x419ed8)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libc.so.6+0x8b7c5) in strlen
==68218==ABORTING
```
Null pointer reference in newVAR_N
This is a GitHub Issue
repo:libming
owner:libming
Title : Null pointer reference in newVAR_N
Issue date:

--- start body ---
Hi, I found a null pointer reference problem.
version: 0.4.8
command: swftophp poc
poc:
[decompile.c_642_11.tar.gz](https://github.com/libming/libming/files/7273121/decompile.c_642_11.tar.gz)

Here is the report from ASAN:
```
header indicates a filesize of 761 but filesize is 162
<?php
$m = new SWFMovie(1);

ming_setscale(1.0);
$m->setRate(128.000000);
$m->setDimension(-18499, 3460);

/* Note: xMin and/or yMin are not 0! */

$m->setFrames(771);

/* SWF_DOACTION */
ASAN:DEADLYSIGNAL
=================================================================
==68218==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7fc2cb4407c6 bp 0x7ffd3db3ca40 sp 0x7ffd3db3c1c8 T0)
==68218==The signal is caused by a READ memory access.
==68218==Hint: address points to the zero page.
    #0 0x7fc2cb4407c5 in strlen (/lib/x86_64-linux-gnu/libc.so.6+0x8b7c5)
    #1 0x43e89c in __interceptor_strlen.part.31 /home/radon/build/llvm_tools/llvm-4.0.0.src/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:282
    #2 0x54a3b2 in newVar_N /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:642:11
    #3 0x540218 in decompileCALLMETHOD /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:2843:9
    #4 0x52c507 in decompileAction /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3267:10
    #5 0x545f60 in decompileActions /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3401:6
    #6 0x544319 in decompileSETTARGET /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3076:3
    #7 0x52ce49 in decompileAction /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3372:10
    #8 0x545f60 in decompileActions /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3401:6
    #9 0x545b66 in decompile5Action /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/decompile.c:3423:2
    #10 0x51f261 in outputSWF_DOACTION /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/outputscript.c:1548:29
    #11 0x51c3c9 in outputBlock /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/outputscript.c:2079:4
    #12 0x52855e in readMovie /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/main.c:277:4
    #13 0x526bbc in main /home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/../../util/main.c:350:2
    #14 0x7fc2cb3d583f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
    #15 0x419ed8 in _start (/home/radon/Documents/project/libming/libming-0_4_8/obj-asan/util/swftophp+0x419ed8)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libc.so.6+0x8b7c5) in strlen
==68218==ABORTING
```
--- end body ---

A null pointer dereference vulnerability in the newVar_N function of libming version 0.4.8 can lead to a segmentation fault when processing specially crafted SWF files. This issue arises when the header indicates a larger filesize than the actual data, causing the program to attempt to read from a null pointer, resulting in a crash.