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Heap use after free in bit_copy_chain in src/bits.c:3318
Affected version
the latest commit: https://github.com/LibreDWG/libredwg/tree/45d2a290c65ed691be0901ba2b2ef51044e07a16 and 0.12.4
What's the problem?
A heap use after free was discovered in bit_copy_chain in src/bits.c:3318.
ASAN report:
$ ./dwgrewrite ./pocs/tests_64233
......
......
......
==3021191==ERROR: AddressSanitizer: heap-use-after-free on address 0x7ffff2b59800 at pc 0x0000004970c7 bp 0x7fffffffba70 sp 0x7fffffffb238
READ of size 282028 at 0x7ffff2b59800 thread T0
#0 0x4970c6 in __asan_memcpy /src/llvm-project-12.0.0.src/compiler-rt/lib/asan/asan_interceptors_memintrinsics.cpp:22:3
#1 0x4e732c in memcpy /usr/include/x86_64-linux-gnu/bits/string_fortified.h:34:10
#2 0x4e732c in bit_copy_chain /src/libredwg/src/bits.c:3318:7
#3 0x102955f in obj_flush_hdlstream /src/libredwg/src/encode.c:784:3
#4 0x159ce6f in dwg_encode_PLANESURFACE_private /src/libredwg/src/./dwg.spec:8832:3
#5 0x12e1e11 in dwg_encode_PLANESURFACE /src/libredwg/src/./dwg.spec:8818:1
#6 0x1005fae in dwg_encode_variable_type /src/libredwg/src/./classes.inc:243:3
#7 0xfe71d6 in dwg_encode_add_object /src/libredwg/src/encode.c:3771:28
#8 0xf98c78 in dwg_encode /src/libredwg/src/encode.c:2352:16
#9 0x4cbcf6 in dwg_write_file /src/libredwg/src/dwg.c:429:11
#10 0x4c939f in main /src/libredwg/programs/dwgrewrite.c:349:11
#11 0x7ffff7c580b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
#12 0x41c3fd in _start (/mnt/disk/out/libredwg/programs_asan/dwgrewrite+0x41c3fd)
0x7ffff2b59800 is located 0 bytes inside of 282624-byte region [0x7ffff2b59800,0x7ffff2b9e800)
freed by thread T0 here:
#0 0x498003 in realloc /src/llvm-project-12.0.0.src/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x4d8122 in bit_chain_alloc /src/libredwg/src/bits.c:3026:30
#2 0x4e7260 in bit_copy_chain /src/libredwg/src/bits.c:3314:5
#3 0x102955f in obj_flush_hdlstream /src/libredwg/src/encode.c:784:3
#4 0x159ce6f in dwg_encode_PLANESURFACE_private /src/libredwg/src/./dwg.spec:8832:3
#5 0x12e1e11 in dwg_encode_PLANESURFACE /src/libredwg/src/./dwg.spec:8818:1
#6 0x1005fae in dwg_encode_variable_type /src/libredwg/src/./classes.inc:243:3
#7 0xfe71d6 in dwg_encode_add_object /src/libredwg/src/encode.c:3771:28
#8 0xf98c78 in dwg_encode /src/libredwg/src/encode.c:2352:16
#9 0x4cbcf6 in dwg_write_file /src/libredwg/src/dwg.c:429:11
#10 0x4c939f in main /src/libredwg/programs/dwgrewrite.c:349:11
#11 0x7ffff7c580b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
previously allocated by thread T0 here:
#0 0x498003 in realloc /src/llvm-project-12.0.0.src/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x4d8122 in bit_chain_alloc /src/libredwg/src/bits.c:3026:30
#2 0xfe5ec7 in dwg_encode_add_object /src/libredwg/src/encode.c:3490:5
#3 0xf98c78 in dwg_encode /src/libredwg/src/encode.c:2352:16
#4 0x4cbcf6 in dwg_write_file /src/libredwg/src/dwg.c:429:11
#5 0x4c939f in main /src/libredwg/programs/dwgrewrite.c:349:11
#6 0x7ffff7c580b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
SUMMARY: AddressSanitizer: heap-use-after-free /src/llvm-project-12.0.0.src/compiler-rt/lib/asan/asan_interceptors_memintrinsics.cpp:22:3 in __asan_memcpy
Shadow bytes around the buggy address:
0x10007e5632b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x10007e5632c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x10007e5632d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x10007e5632e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x10007e5632f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x10007e563300:[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x10007e563310: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x10007e563320: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x10007e563330: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x10007e563340: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
0x10007e563350: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
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
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
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
Shadow gap: cc
==3021191==ABORTING
Compile command
CC="clang" CFLAGS="-O1 -g -fsanitize=address" ./configure --enable-release --disable-shared && make
How can we reproduce the issue?
unzip tests_64233.zip
dwgrewrite ./tests_64233
POC file :
tests_64233.zip