Created attachment 1299841 [details]
Triggered by "./sassc POC"
Description of problem:
There is an illegal address access in eval.cpp of libsass
Version-Release number of selected component (if applicable):
<= latest version
Steps to Reproduce:
The debugging information is as follows:
$ ./sassc POC
Program received signal SIGSEGV, Segmentation fault.
Sass::Eval::operator() (this=0x7fffffffde20, m=0x646820) at eval.cpp:526
526 Expression_Ptr ex_val = m->at(key)->perform(this);
#0 Sass::Eval::operator() (this=0x7fffffffde20, m=0x646820) at eval.cpp:526
#1 0x00007ffff79ace11 in Sass::Eval::operator() (this=0x7fffffffde20, l=0x631630) at eval.cpp:491
#2 0x00007ffff79b053f in Sass::Eval::operator() (this=0x7fffffffde20, b_in=<optimized out>) at eval.cpp:721
#3 0x00007ffff79acbc3 in Sass::Eval::operator() (this=0x7fffffffde20, l=0x631080) at eval.cpp:503
#4 0x00007ffff79f2bb4 in Sass::Expand::operator() (this=<optimized out>, a=<optimized out>) at expand.cpp:330
#5 0x00007ffff7a09771 in Sass::Expand::append_block (this=0x7fffffffde10, b=<optimized out>) at expand.cpp:799
#6 0x00007ffff79e9f89 in Sass::Expand::operator() (this=0x7fffffffde10, b=0x630f10) at expand.cpp:81
#7 0x00007ffff7800358 in Sass::Context::compile (this=0x62ff40) at context.cpp:659
#8 0x00007ffff77fd303 in Sass::File_Context::parse (this=0x62ff40) at context.cpp:588
#9 0x00007ffff7b16376 in Sass::sass_parse_block (compiler=0x630480) at sass_context.cpp:227
#10 sass_compiler_parse (compiler=0x630480) at sass_context.cpp:476
#11 0x00007ffff7b15562 in sass_compile_context (c_ctx=0x62fda0, cpp_ctx=0x7ffff7fda050) at sass_context.cpp:364
#12 0x00007ffff7b1592a in sass_compile_file_context (file_ctx=0x62fda0) at sass_context.cpp:463
#13 0x0000000000402796 in compile_file (options=0x62fd20, input_path=<optimized out>, outfile=0x0) at sassc.c:145
#14 0x0000000000403117 in main (argc=<optimized out>, argv=<optimized out>) at sassc.c:335
The asan debug info is as follows:
==31154==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f1450d3b64d bp 0x7ffdff76db10 sp 0x7ffdff76d8c0 T0)
#0 0x7f1450d3b64c (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x53664c)
#1 0x7f1450d3a3e2 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x5353e2)
#2 0x7f1450d3feaa (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x53aeaa)
#3 0x7f1450d3a14e (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x53514e)
#4 0x7f1450daba49 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x5a6a49)
#5 0x7f1450dcf9da (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x5ca9da)
#6 0x7f1450d9d71a (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x59871a)
#7 0x7f1450a931aa (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x28e1aa)
#8 0x7f1450a8e3b3 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x2893b3)
#9 0x7f1450f9fe60 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x79ae60)
#10 0x7f1450f9eaa1 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x799aa1)
#11 0x7f1450f9eee1 (/home/icy/secreal/libsass-asan/install/lib/libsass.so.1+0x799ee1)
#12 0x4ddfc5 (/home/icy/secreal/sassc-asan/install/bin/sassc+0x4ddfc5)
#13 0x4debe5 (/home/icy/secreal/sassc-asan/install/bin/sassc+0x4debe5)
#14 0x7f144f590a3f (/lib/x86_64-linux-gnu/libc.so.6+0x20a3f)
#15 0x436508 (/home/icy/secreal/sassc-asan/install/bin/sassc+0x436508)
AddressSanitizer can not provide additional info.
This vulnerability is detected by team OWL337, with our custom fuzzer collAFL. Please contact email@example.com and firstname.lastname@example.org if you need more info about the team, the tool or the vulnerability.
Reported upstream as https://github.com/sass/libsass/issues/2446
This bug appears to have been reported against 'rawhide' during the Fedora 27 development cycle.
Changing version to '27'.
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