## Affected version
the lastest version https://github.com/LibreDWG/libredwg/tree/0.12.4.4348

## What's the problem?

A null pointer deference was discovered in function output_SVG in dwg2SVG.c
ASAN report:
```
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   xmlns:xlink="http://www.w3.org/1999/xlink"
   version="1.1" baseProfile="basic"
   width="100%" height="100%"
   viewBox="-12.019621 -58.848308 37.409022 104.239317">
        <defs>
AddressSanitizer:DEADLYSIGNAL
=================================================================
==4105970==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x55ebc7a930f5 bp 0x7ffcd4596f20 sp 0x7ffcd4596ef0 T0)
==4105970==The signal is caused by a READ memory access.
==4105970==Hint: address points to the zero page.
    #0 0x55ebc7a930f4 in output_SVG /libredwg/programs/dwg2SVG.c:862
    #1 0x55ebc7a93b59 in main /libredwg/programs/dwg2SVG.c:980
    #2 0x7fcb3a58c0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x55ebc7a8ac0d in _start (/libredwg/fuzz/asan+0x209c0d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /libredwg/programs/dwg2SVG.c:862 in output_SVG
==4105970==ABORTING

```
## Compile command

CC="afl-clang-lto" CFLAGS="-g -fsanitize=address" ./configure --enable-release --disable-shared && make

## How can we reproduce the issue?

./dwg2SVG [poc]

POC file:
[id_000000,sig_11,src_010799,time_76993507,op_ext_AO,pos_1249.zip](https://github.com/LibreDWG/libredwg/files/7074864/id_000000.sig_11.src_010799.time_76993507.op_ext_AO.pos_1249.zip)


null pointer deference in function output_SVG in dwg2SVG.c
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : null pointer deference in function output_SVG in dwg2SVG.c
Issue date:

--- start body ---
## Affected version
the lastest version https://github.com/LibreDWG/libredwg/tree/0.12.4.4348

## What's the problem?

A null pointer deference was discovered in function output_SVG in dwg2SVG.c
ASAN report:
```
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   xmlns:xlink="http://www.w3.org/1999/xlink"
   version="1.1" baseProfile="basic"
   width="100%" height="100%"
   viewBox="-12.019621 -58.848308 37.409022 104.239317">
        <defs>
AddressSanitizer:DEADLYSIGNAL
=================================================================
==4105970==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x55ebc7a930f5 bp 0x7ffcd4596f20 sp 0x7ffcd4596ef0 T0)
==4105970==The signal is caused by a READ memory access.
==4105970==Hint: address points to the zero page.
    #0 0x55ebc7a930f4 in output_SVG /libredwg/programs/dwg2SVG.c:862
    #1 0x55ebc7a93b59 in main /libredwg/programs/dwg2SVG.c:980
    #2 0x7fcb3a58c0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x55ebc7a8ac0d in _start (/libredwg/fuzz/asan+0x209c0d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /libredwg/programs/dwg2SVG.c:862 in output_SVG
==4105970==ABORTING

```
## Compile command

CC="afl-clang-lto" CFLAGS="-g -fsanitize=address" ./configure --enable-release --disable-shared && make

## How can we reproduce the issue?

./dwg2SVG [poc]

POC file:
[id_000000,sig_11,src_010799,time_76993507,op_ext_AO,pos_1249.zip](https://github.com/LibreDWG/libredwg/files/7074864/id_000000.sig_11.src_010799.time_76993507.op_ext_AO.pos_1249.zip)


--- end body ---
