stack-buffer-overflow exists in the function copy_bytes in decode_r2007.c

[cxlzff]

system info

Ubuntu x86_64, clang 6.0, dwg2dxf(0.12.4.4608)

Command line

./programs/dwg2dxf -b -m @@ -o /dev/null

AddressSanitizer output

==9543==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fffffffc8f0 at pc 0x0000007257bb bp 0x7fffffffbc90 sp 0x7fffffffbc88 WRITE of size 1 at 0x7fffffffc8f0 thread T0 #0 0x7257ba in copy_bytes /testcase/libredwg/src/decode_r2007.c:228:12 #1 0x7257ba in decompress_r2007 /testcase/libredwg/src/decode_r2007.c:563 #2 0x712263 in read_file_header /testcase/libredwg/src/decode_r2007.c:1247:13 #3 0x712263 in read_r2007_meta_data /testcase/libredwg/src/decode_r2007.c:2354 #4 0x533116 in decode_R2007 /testcase/libredwg/src/decode.c:3231:11 #5 0x533116 in dwg_decode /testcase/libredwg/src/decode.c:212 #6 0x50d759 in dwg_read_file /testcase/libredwg/src/dwg.c:254:11 #7 0x50c454 in main /testcase/libredwg/programs/dwg2dxf.c:258:15 #8 0x7ffff6e22c86 in __libc_start_main /build/glibc-CVJwZb/glibc-2.27/csu/../csu/libc-start.c:310 #9 0x419ee9 in _start (/testcase/libredwg/programs/dwg2dxf+0x419ee9)

Address 0x7fffffffc8f0 is located in stack of thread T0 at offset 2736 in frame #0 0x71159f in read_r2007_meta_data /testcase/libredwg/src/decode_r2007.c:2338

This frame has 23 object(s): [32, 40) 'acis_sab_data.i.i' [64, 65) 'acis_empty.i.i' [80, 82) 'version1913.i.i' [96, 100) 'size1930.i.i' [112, 160) 'sec_dat.i548' [192, 240) 'sec_dat.i515' [272, 320) 'sec_dat.i492' [352, 400) 'sec_dat.i455' [432, 480) 'sec_dat.i424' [512, 560) 'sec_dat.i391' [592, 640) 'sec_dat.i356' [672, 720) 'sec_dat.i330' [752, 800) 'sec_dat.i301' [832, 836) 'size.i282' [848, 873) 'old_dat.sroa.0.i' [912, 960) 'sec_dat.i268' [992, 1040) 'sec_dat.i220' [1072, 1120) 'str.i' [1152, 1200) 'sec_dat.i' [1232, 1280) 'str_dat.i' [1312, 1320) 'ptr.i' [1344, 2328) 'data.i' [2464, 2736) 'file_header' <== Memory access at offset 2736 overflows this variable HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext (longjmp and C++ exceptions are supported) SUMMARY: AddressSanitizer: stack-buffer-overflow /testcase/libredwg/src/decode_r2007.c:228:12 in copy_bytes Shadow bytes around the buggy address: 0x10007fff78c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff78d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff78e0: 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 0x10007fff78f0: f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 0x10007fff7900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 =>0x10007fff7910: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[f3]f3 0x10007fff7920: f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 0x10007fff7930: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7940: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7950: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x10007fff7960: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 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 ==9543==ABORTING

poc

https://gitee.com/cxlzff/fuzz-poc/raw/master/libredwg/copy_bytes_sof

[abergmann]

CVE-2022-33034 was assigned to this issue.

[rurban]

repro in v0.12.5, the latest release

[rurban]

This is now fixed, leading to a fatal copy_bytes: dst 0x7fff508eaede + 19 > 0x7fff508eaef0 ERROR: Decompression error: length overflow