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验证：
体验盒子Source: https://code.google.com/p/google-security-research/issues/detail?id=637
The following crash due to a heap-based out-of-bounds memory read can be observed in an ASAN build of latest stable libxml2 (2.9.3, released 4 days ago), by feeding a malformed file to xmllint ("$ ./xmllint --html /path/to/file"):
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==25920==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x631000010810 at pc 0x0000004a2f25 bp 0x7ffc81805ae0 sp 0x7ffc81805290
READ of size 73661 at 0x631000010810 thread T0
#0 0x4a2f24 in __asan_memcpy llvm/projects/compiler-rt/lib/asan/asan_interceptors.cc:393
#1 0xd026b2 in xmlDictAddString libxml2-2.9.3/dict.c:285:5
#2 0xd009e8 in xmlDictLookup libxml2-2.9.3/dict.c:926:11
#3 0x806e4d in htmlParseNameComplex libxml2-2.9.3/HTMLparser.c:2517:12
#4 0x7cc29d in htmlParseName libxml2-2.9.3/HTMLparser.c:2483:12
#5 0x7ca6f1 in htmlParseEntityRef libxml2-2.9.3/HTMLparser.c:2682:16
#6 0x820a0d in htmlParseReference libxml2-2.9.3/HTMLparser.c:4044:8
#7 0x7df716 in htmlParseContentInternal libxml2-2.9.3/HTMLparser.c:4619:3
#8 0x7e2f0f in htmlParseDocument libxml2-2.9.3/HTMLparser.c:4769:5
#9 0x802c55 in htmlDoRead libxml2-2.9.3/HTMLparser.c:6741:5
#10 0x8030b6 in htmlReadFile libxml2-2.9.3/HTMLparser.c:6799:13
#11 0x4f47a5 in parseAndPrintFile libxml2-2.9.3/xmllint.c:2248:8
#12 0x4ebe8f in main libxml2-2.9.3/xmllint.c:3759:7
0x631000010810 is located 0 bytes to the right of 65552-byte region [0x631000000800,0x631000010810)
allocated by thread T0 here:
#0 0x4b8ef0 in realloc llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:61
#1 0xa079a5 in xmlBufGrowInternal libxml2-2.9.3/buf.c:486:23
#2 0xa06722 in xmlBufGrow libxml2-2.9.3/buf.c:515:11
#3 0x72fef4 in xmlParserInputBufferGrow libxml2-2.9.3/xmlIO.c:3326:9
#4 0x543b22 in xmlParserInputGrow libxml2-2.9.3/parserInternals.c:320:8
#5 0x8067f4 in htmlParseNameComplex libxml2-2.9.3/HTMLparser.c:2511:6
#6 0x7cc29d in htmlParseName libxml2-2.9.3/HTMLparser.c:2483:12
#7 0x7ca6f1 in htmlParseEntityRef libxml2-2.9.3/HTMLparser.c:2682:16
#8 0x820a0d in htmlParseReference libxml2-2.9.3/HTMLparser.c:4044:8
#9 0x7df716 in htmlParseContentInternal libxml2-2.9.3/HTMLparser.c:4619:3
#10 0x7e2f0f in htmlParseDocument libxml2-2.9.3/HTMLparser.c:4769:5
#11 0x802c55 in htmlDoRead libxml2-2.9.3/HTMLparser.c:6741:5
#12 0x8030b6 in htmlReadFile libxml2-2.9.3/HTMLparser.c:6799:13
#13 0x4f47a5 in parseAndPrintFile libxml2-2.9.3/xmllint.c:2248:8
#14 0x4ebe8f in main libxml2-2.9.3/xmllint.c:3759:7
SUMMARY: AddressSanitizer: heap-buffer-overflow llvm/projects/compiler-rt/lib/asan/asan_interceptors.cc:393 in __asan_memcpy
Shadow bytes around the buggy address:
0x0c627fffa0b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c627fffa0c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c627fffa0d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c627fffa0e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c627fffa0f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c627fffa100: 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c627fffa110: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c627fffa120: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c627fffa130: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c627fffa140: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c627fffa150: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
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
Heap right redzone:fb
Freed heap region: fd
Stack left redzone:f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
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
==25920==ABORTING
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The crash was reported at https://bugzilla.gnome.org/show_bug.cgi?id=758605. Attached is an XML file which triggers the crash.
Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39491.zip
体验盒子
