Graphite2 – NameTable::getName Multiple Heap Out-of-Bounds Reads

Exploit Database
117 阅读

作者： Google Security Research

日期： 2016-05-26
类别：
- dos
平台：
- multiple
来源：https://www.exploit-db.com/exploits/39863/

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Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=756

We have encountered several different crashes in the graphite2::NameTable::getName method, observed in an ASAN build of the standard Graphite2 gr2FontTest utility (git trunk), triggered with the following command:

$ ./gr2fonttest -demand -cache /path/to/file

Below are three unique ASAN reports that we have triggered.

--- cut ---

==1191==ERROR: AddressSanitizer: SEGV on unknown address 0x61b000026b15 (pc 0x000000553c81 bp 0x7ffc0e24a820 sp 0x7ffc0e24a800 T0)

#0 0x553c80 in unsigned long be::_peek<1>(unsigned char const*) graphite/src/./inc/Endian.h:77:73

#1 0x553bd3 in unsigned long be::_peek<2>(unsigned char const*) graphite/src/./inc/Endian.h:50:16

#2 0x5516cb in unsigned short be::read<unsigned short>(unsigned char const*&) graphite/src/./inc/Endian.h:60:23

#3 0x59192b in graphite2::NameTable::getName(unsigned short&, unsigned short, gr_encform, unsigned int&) graphite/src/NameTable.cpp:157:24

#4 0x572e5c in gr_fref_label graphite/src/gr_features.cpp:97:12

#5 0x4eaec8 in Parameters::printFeatures(gr_face const*) const (graphite/gr2fonttest/gr2fonttest+0x4eaec8)

#6 0x4ed32b in Parameters::testFileFont() const (graphite/gr2fonttest/gr2fonttest+0x4ed32b)

#7 0x4f06c9 in main (graphite/gr2fonttest/gr2fonttest+0x4f06c9)

AddressSanitizer can not provide additional info.

SUMMARY: AddressSanitizer: SEGV graphite/src/./inc/Endian.h:77:73 in unsigned long be::_peek<1>(unsigned char const*)

==1191==ABORTING

--- cut ---

==1199==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61b00001fb95 at pc 0x000000553c7d bp 0x7ffdebef2a70 sp 0x7ffdebef2a68

READ of size 1 at 0x61b00001fb95 thread T0

#0 0x553c7c in unsigned long be::_peek<1>(unsigned char const*) graphite/src/./inc/Endian.h:77:73

#1 0x553bd3 in unsigned long be::_peek<2>(unsigned char const*) graphite/src/./inc/Endian.h:50:16

#2 0x5516cb in unsigned short be::read<unsigned short>(unsigned char const*&) graphite/src/./inc/Endian.h:60:23

#3 0x59192b in graphite2::NameTable::getName(unsigned short&, unsigned short, gr_encform, unsigned int&) graphite/src/NameTable.cpp:157:24

#4 0x572e5c in gr_fref_label graphite/src/gr_features.cpp:97:12

#5 0x4eaec8 in Parameters::printFeatures(gr_face const*) const (graphite/gr2fonttest/gr2fonttest+0x4eaec8)

#6 0x4ed32b in Parameters::testFileFont() const (graphite/gr2fonttest/gr2fonttest+0x4ed32b)

#7 0x4f06c9 in main (graphite/gr2fonttest/gr2fonttest+0x4f06c9)

AddressSanitizer can not describe address in more detail (wild memory access suspected).

SUMMARY: AddressSanitizer: heap-buffer-overflow graphite/src/./inc/Endian.h:77:73 in unsigned long be::_peek<1>(unsigned char const*)

Shadow bytes around the buggy address:

0x0c367fffbf20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

=>0x0c367fffbf70: fa fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbf90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbfa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbfb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c367fffbfc0: 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

==1199==ABORTING

--- cut ---

==1315==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60400000db3a at pc 0x00000057d59d bp 0x7ffd01d33840 sp 0x7ffd01d33838

READ of size 2 at 0x60400000db3a thread T0

#0 0x57d59c in graphite2::_utf_codec<16>::get(unsigned short const*, signed char&) graphite/src/./inc/UtfCodec.h:97:27

#1 0x57d0a7 in graphite2::_utf_iterator<unsigned short const>::reference::operator unsigned int() const graphite/src/./inc/UtfCodec.h:173:74

#2 0x591d32 in graphite2::NameTable::getName(unsigned short&, unsigned short, gr_encform, unsigned int&) graphite/src/NameTable.cpp:173:18

#3 0x572e5c in gr_fref_label graphite/src/gr_features.cpp:97:12

#4 0x4eaec8 in Parameters::printFeatures(gr_face const*) const (graphite/gr2fonttest/gr2fonttest+0x4eaec8)

#5 0x4ed32b in Parameters::testFileFont() const (graphite/gr2fonttest/gr2fonttest+0x4ed32b)

#6 0x4f06c9 in main (graphite/gr2fonttest/gr2fonttest+0x4f06c9)

0x60400000db3a is located 0 bytes to the right of 42-byte region [0x60400000db10,0x60400000db3a)

allocated by thread T0 here:

#0 0x4b85b8 in malloc llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:40

#1 0x55a24a in unsigned short* graphite2::gralloc<unsigned short>(unsigned long) graphite/src/./inc/Main.h:88:28

#2 0x5916ef in graphite2::NameTable::getName(unsigned short&, unsigned short, gr_encform, unsigned int&) graphite/src/NameTable.cpp:147:37

#3 0x572e5c in gr_fref_label graphite/src/gr_features.cpp:97:12

#4 0x4eaec8 in Parameters::printFeatures(gr_face const*) const (graphite/gr2fonttest/gr2fonttest+0x4eaec8)

#5 0x4ed32b in Parameters::testFileFont() const (graphite/gr2fonttest/gr2fonttest+0x4ed32b)

#6 0x4f06c9 in main (graphite/gr2fonttest/gr2fonttest+0x4f06c9)

SUMMARY: AddressSanitizer: heap-buffer-overflow graphite/src/./inc/UtfCodec.h:97:27 in graphite2::_utf_codec<16>::get(unsigned short const*, signed char&)

Shadow bytes around the buggy address:

0x0c087fff9b10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c087fff9b20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c087fff9b30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c087fff9b40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

0x0c087fff9b50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

=>0x0c087fff9b60: fa fa 00 00 00 00 00[02]fa fa fd fd fd fd fd fd

0x0c087fff9b70: fa fa fd fd fd fd fd fa fa fa fd fd fd fd fd fd

0x0c087fff9b80: fa fa fd fd fd fd fd fd fa fa 00 00 00 00 00 00

0x0c087fff9b90: fa fa 00 00 00 00 00 fa fa fa fd fd fd fd fd fa

0x0c087fff9ba0: fa fa fd fd fd fd fd fd fa fa fd fd fd fd fd fa

0x0c087fff9bb0: fa fa fd fd fd fd fd fa fa fa 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

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

==1315==ABORTING

--- cut ---

The bug was reported at https://bugzilla.mozilla.org/show_bug.cgi?id=1254497. Attached are three font files which reproduce the crashes.

Proof of Concept:

https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39863.zip