LibreDWG v0.12.4.4643 was discovered to contain a heap buffer overflow via the function decode_preR13_section_hdr at decode_r11.c.
**System info**
Ubuntu x86_64, clang 10.0
version: 0.12.4.4643, last commit [93c2512](https://github.com/LibreDWG/libredwg/commit/93c25124c191987af168ace9fe4b5623061874bd)

**Command line**
./dwg2dxf poc

**Poc**
poc: [poc](https://github.com/iorra-cifer/Poc/blob/main/libredwg/heap-buffer-overflow?raw=true)

**AddressSanitizer output**
==4080011==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x618000000428 at pc 0x000000480860 bp 0x7ffddb1de850 sp 0x7ffddb1de008
WRITE of size 63 at 0x618000000428 thread T0
    #0 0x48085f in strncpy /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:483:5
    #1 0x1123350 in decode_preR13_section_hdr /home/SVF-tools/example/libredwg-2/src/decode_r11.c:139:3
    #2 0x111d7e1 in decode_preR13 /home/SVF-tools/example/libredwg-2/src/decode_r11.c:762:7
    #3 0x4fb4b6 in dwg_decode /home/SVF-tools/example/libredwg-2/src/decode.c:211:17
    #4 0x4c6dcc in dwg_read_file /home/SVF-tools/example/libredwg-2/src/dwg.c:254:11
    #5 0x4c4a40 in main /home/SVF-tools/example/libredwg-2/programs/dwg2dxf.c:258:15
    #6 0x7f7873298c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310
    #7 0x41b649 in _start (/home/SVF-tools/example/libredwg-2/fuzz/dwg2dxf.ci+0x41b649)

0x618000000428 is located 24 bytes inside of 442820362-byte region [0x618000000410,0x61801a64eb1a)
==4080011==AddressSanitizer CHECK failed: /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_descriptions.cpp:175 "((id)) != (0)" (0x0, 0x0)
    #0 0x49bf3e in __asan::AsanCheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:73:5
    #1 0x4b045f in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /home/brian/src/final/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_termination.cpp:78:5
    #2 0x4245db in __asan::HeapAddressDescription::Print() const /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_descriptions.cpp
    #3 0x427425 in __asan::ErrorGeneric::Print() /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_errors.cpp:591:20
    #4 0x497ba8 in __asan::ScopedInErrorReport::~ScopedInErrorReport() /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_report.cpp:141:50
    #5 0x4997dd in __asan::ReportGenericError(unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long, unsigned int, bool) /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_report.cpp:474:1
    #6 0x480881 in strncpy /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:483:5
    #7 0x1123350 in decode_preR13_section_hdr /home/SVF-tools/example/libredwg-2/src/decode_r11.c:139:3
    #8 0x111d7e1 in decode_preR13 /home/SVF-tools/example/libredwg-2/src/decode_r11.c:762:7
    #9 0x4fb4b6 in dwg_decode /home/SVF-tools/example/libredwg-2/src/decode.c:211:17
    #10 0x4c6dcc in dwg_read_file /home/SVF-tools/example/libredwg-2/src/dwg.c:254:11
    #11 0x4c4a40 in main /home/SVF-tools/example/libredwg-2/programs/dwg2dxf.c:258:15
    #12 0x7f7873298c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310
    #13 0x41b649 in _start (/home/SVF-tools/example/libredwg-2/fuzz/dwg2dxf.ci+0x41b649)


heap-buffer-overflow exists in the function decode_preR13_section_hdr in decode_r11.c
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : heap-buffer-overflow exists in the function decode_preR13_section_hdr in decode_r11.c
Issue date:

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**System info**
Ubuntu x86_64, clang 10.0
version: 0.12.4.4643, last commit [93c2512](https://github.com/LibreDWG/libredwg/commit/93c25124c191987af168ace9fe4b5623061874bd)

**Command line**
./dwg2dxf poc

**Poc**
poc: [poc](https://github.com/iorra-cifer/Poc/blob/main/libredwg/heap-buffer-overflow?raw=true)

**AddressSanitizer output**
==4080011==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x618000000428 at pc 0x000000480860 bp 0x7ffddb1de850 sp 0x7ffddb1de008
WRITE of size 63 at 0x618000000428 thread T0
    #0 0x48085f in strncpy /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:483:5
    #1 0x1123350 in decode_preR13_section_hdr /home/SVF-tools/example/libredwg-2/src/decode_r11.c:139:3
    #2 0x111d7e1 in decode_preR13 /home/SVF-tools/example/libredwg-2/src/decode_r11.c:762:7
    #3 0x4fb4b6 in dwg_decode /home/SVF-tools/example/libredwg-2/src/decode.c:211:17
    #4 0x4c6dcc in dwg_read_file /home/SVF-tools/example/libredwg-2/src/dwg.c:254:11
    #5 0x4c4a40 in main /home/SVF-tools/example/libredwg-2/programs/dwg2dxf.c:258:15
    #6 0x7f7873298c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310
    #7 0x41b649 in _start (/home/SVF-tools/example/libredwg-2/fuzz/dwg2dxf.ci+0x41b649)

0x618000000428 is located 24 bytes inside of 442820362-byte region [0x618000000410,0x61801a64eb1a)
==4080011==AddressSanitizer CHECK failed: /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_descriptions.cpp:175 "((id)) != (0)" (0x0, 0x0)
    #0 0x49bf3e in __asan::AsanCheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:73:5
    #1 0x4b045f in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /home/brian/src/final/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_termination.cpp:78:5
    #2 0x4245db in __asan::HeapAddressDescription::Print() const /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_descriptions.cpp
    #3 0x427425 in __asan::ErrorGeneric::Print() /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_errors.cpp:591:20
    #4 0x497ba8 in __asan::ScopedInErrorReport::~ScopedInErrorReport() /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_report.cpp:141:50
    #5 0x4997dd in __asan::ReportGenericError(unsigned long, unsigned long, unsigned long, unsigned long, bool, unsigned long, unsigned int, bool) /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_report.cpp:474:1
    #6 0x480881 in strncpy /home/brian/src/final/llvm-project/compiler-rt/lib/asan/asan_interceptors.cpp:483:5
    #7 0x1123350 in decode_preR13_section_hdr /home/SVF-tools/example/libredwg-2/src/decode_r11.c:139:3
    #8 0x111d7e1 in decode_preR13 /home/SVF-tools/example/libredwg-2/src/decode_r11.c:762:7
    #9 0x4fb4b6 in dwg_decode /home/SVF-tools/example/libredwg-2/src/decode.c:211:17
    #10 0x4c6dcc in dwg_read_file /home/SVF-tools/example/libredwg-2/src/dwg.c:254:11
    #11 0x4c4a40 in main /home/SVF-tools/example/libredwg-2/programs/dwg2dxf.c:258:15
    #12 0x7f7873298c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310
    #13 0x41b649 in _start (/home/SVF-tools/example/libredwg-2/fuzz/dwg2dxf.ci+0x41b649)


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