AddressSanitizer: heap-buffer-overflow

[E4ck]

A heap-buffer-overflow in prelexer.hpp:69:14 in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*)

Compile and reproduce:
CC=afl-clang-fast CXX=afl-clang-fast++ AFL_USE_ASAN=1 make -C sassc -j4

ldd:

$ ldd sassc
	linux-vdso.so.1 =>  (0x00007fffc6365000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f731150d000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f7311204000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f7310e82000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f7310c65000)
	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f7310a5d000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f7310847000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f731047d000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f7311711000)

System information:
Linux ubuntu64 4.15.0-29-generic #31~16.04.1-Ubuntu SMP Wed Jul 18 08:54:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Version: libsass-3.5.5、sassc-3.4.8

Poc: crash147.zip

Run: cat crash147 | ./sassc

ASAN:

=================================================================
==3354==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60700000006a at pc 0x0000009591ef bp 0x7ffe65ea3260 sp 0x7ffe65ea3258
READ of size 1 at 0x60700000006a thread T0
    #0 0x9591ee in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/prelexer.hpp:69:14
    #1 0x958d3a in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212:14
    #2 0x958d3a in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::number, &Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212
    #3 0x958d3a in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::quoted_string, &Sass::Prelexer::number, &Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212
    #4 0x946c2c in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::identifier, &Sass::Prelexer::quoted_string, &Sass::Prelexer::number, &Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212:14
    #5 0x946c2c in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::identifier_schema, &Sass::Prelexer::identifier, &Sass::Prelexer::quoted_string, &Sass::Prelexer::number, &Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212
    #6 0x946c2c in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::variable, &Sass::Prelexer::identifier_schema, &Sass::Prelexer::identifier, &Sass::Prelexer::quoted_string, &Sass::Prelexer::number, &Sass::Prelexer::hex, &Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*) /home/eack/libsass/src/lexer.hpp:212
    #7 0x946c2c in Sass::Prelexer::ie_keyword_arg_value(char const*) /home/eack/libsass/src/prelexer.cpp:1321
    #8 0x946dee in char const* Sass::Prelexer::sequence<&Sass::Prelexer::ie_keyword_arg_value>(char const*) /home/eack/libsass/src/lexer.hpp:221:20
    #9 0x946dee in char const* Sass::Prelexer::sequence<&Sass::Prelexer::optional_css_whitespace, &Sass::Prelexer::ie_keyword_arg_value>(char const*) /home/eack/libsass/src/lexer.hpp:228
    #10 0x946dee in char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)61>(char const*)), &Sass::Prelexer::optional_css_whitespace, &Sass::Prelexer::ie_keyword_arg_value>(char const*) /home/eack/libsass/src/lexer.hpp:228
    #11 0x946dee in char const* Sass::Prelexer::sequence<&Sass::Prelexer::optional_css_whitespace, &(char const* Sass::Prelexer::exactly<(char)61>(char const*)), &Sass::Prelexer::optional_css_whitespace, &Sass::Prelexer::ie_keyword_arg_value>(char const*) /home/eack/libsass/src/lexer.hpp:228
    #12 0x946dee in char const* Sass::Prelexer::sequence<&Sass::Prelexer::ie_keyword_arg_property, &Sass::Prelexer::optional_css_whitespace, &(char const* Sass::Prelexer::exactly<(char)61>(char const*)), &Sass::Prelexer::optional_css_whitespace, &Sass::Prelexer::ie_keyword_arg_value>(char const*) /home/eack/libsass/src/lexer.hpp:228
    #13 0x946dee in Sass::Prelexer::ie_keyword_arg(char const*) /home/eack/libsass/src/prelexer.cpp:1340
    #14 0x899ce2 in char const* Sass::Parser::peek<&Sass::Prelexer::ie_keyword_arg>(char const*) /home/eack/libsass/src/parser.hpp:136:27
    #15 0x899ce2 in Sass::Parser::parse_factor() /home/eack/libsass/src/parser.cpp:1470
    #16 0x891636 in Sass::Parser::parse_operators() /home/eack/libsass/src/parser.cpp:1416:29
    #17 0x886677 in Sass::Parser::parse_expression() /home/eack/libsass/src/parser.cpp:1375:26
    #18 0x88272c in Sass::Parser::parse_relation() /home/eack/libsass/src/parser.cpp:1320:26
    #19 0x87f37e in Sass::Parser::parse_conjunction() /home/eack/libsass/src/parser.cpp:1297:26
    #20 0x87d34e in Sass::Parser::parse_disjunction() /home/eack/libsass/src/parser.cpp:1275:27
    #21 0x83bc1b in Sass::Parser::parse_space_list() /home/eack/libsass/src/parser.cpp:1247:28
    #22 0x87ae39 in Sass::Parser::parse_comma_list(bool) /home/eack/libsass/src/parser.cpp:1216:27
    #23 0x835b3e in Sass::Parser::parse_list(bool) /home/eack/libsass/src/parser.cpp:1200:12
    #24 0x830d9b in Sass::Parser::parse_declaration() /home/eack/libsass/src/parser.cpp:1074:17
    #25 0x7fa3d2 in Sass::Parser::parse_block_node(bool) /home/eack/libsass/src/parser.cpp:309:30
    #26 0x7eee86 in Sass::Parser::parse_block_nodes(bool) /home/eack/libsass/src/parser.cpp:197:11
    #27 0x7f379f in Sass::Parser::parse_css_block(bool) /home/eack/libsass/src/parser.cpp:154:10
    #28 0x81ce00 in Sass::Parser::parse_block(bool) /home/eack/libsass/src/parser.cpp:178:12
    #29 0x81ce00 in Sass::Parser::parse_ruleset(Lookahead) /home/eack/libsass/src/parser.cpp:538
    #30 0x7f8c3b in Sass::Parser::parse_block_node(bool) /home/eack/libsass/src/parser.cpp:279:21
    #31 0x7eee86 in Sass::Parser::parse_block_nodes(bool) /home/eack/libsass/src/parser.cpp:197:11
    #32 0x7ea18f in Sass::Parser::parse() /home/eack/libsass/src/parser.cpp:123:5
    #33 0x611d5b in Sass::Context::register_resource(Sass::Include const&, Sass::Resource const&) /home/eack/libsass/src/context.cpp:324:24
    #34 0x62e930 in Sass::Data_Context::parse() /home/eack/libsass/src/context.cpp:636:5
    #35 0x5b9926 in Sass::sass_parse_block(Sass_Compiler*) /home/eack/libsass/src/sass_context.cpp:234:31
    #36 0x5b9926 in sass_compiler_parse /home/eack/libsass/src/sass_context.cpp:483
    #37 0x5b85c2 in sass_compile_context(Sass_Context*, Sass::Context*) /home/eack/libsass/src/sass_context.cpp:371:7
    #38 0x5b81ac in sass_compile_data_context /home/eack/libsass/src/sass_context.cpp:456:12
    #39 0x5a7069 in compile_stdin /home/eack/sassc/sassc.c:138:5
    #40 0x5a81ed in main /home/eack/sassc/sassc.c:375:18
    #41 0x7fdf02f2c82f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
    #42 0x4aad88 in _start (/home/eack/sassc/bin/sassc+0x4aad88)

0x60700000006a is located 0 bytes to the right of 74-byte region [0x607000000020,0x60700000006a)
allocated by thread T0 here:
    #0 0x56f420 in realloc /home/eack/llvm-install/llvm-6.0.1.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:107
    #1 0x5a6f22 in compile_stdin /home/eack/sassc/sassc.c:112:25
    #2 0x5a81ed in main /home/eack/sassc/sassc.c:375:18
    #3 0x7fdf02f2c82f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/eack/libsass/src/prelexer.hpp:69:14 in char const* Sass::Prelexer::alternatives<&Sass::Prelexer::hexa, &(char const* Sass::Prelexer::sequence<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::skip_over_scopes<&(char const* Sass::Prelexer::exactly<(char)40>(char const*)), &(char const* Sass::Prelexer::exactly<(char)41>(char const*))>(char const*))>(char const*))>(char const*)
Shadow bytes around the buggy address:
  0x0c0e7fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c0e7fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c0e7fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c0e7fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c0e7fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c0e7fff8000: fa fa fa fa 00 00 00 00 00 00 00 00 00[02]fa fa
  0x0c0e7fff8010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8050: 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
  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
==3354==ABORTING

[fgeek]

CVE-2019-6284 has been assigned for this vulnerability