Bug 1471782 - There is an illegal address access in eval.cpp of libsass
There is an illegal address access in eval.cpp of libsass
Status: NEW
Product: Fedora
Classification: Fedora
Component: sassc (Show other bugs)
x86_64 Linux
unspecified Severity urgent
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Assigned To: Aurelien Bompard
Fedora Extras Quality Assurance
: Security
Depends On:
Blocks: CVE-2017-11554/CVE-2017-11555/CVE-2017-11556/CVE-2017-11605/CVE-2017-11608/CVE-2017-12962/CVE-2017-12963/CVE-2017-12964
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Reported: 2017-07-17 08:33 EDT by owl337
Modified: 2017-08-15 05:11 EDT (History)
1 user (show)

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Attachments (Terms of Use)
Triggered by "./sassc POC" (119 bytes, application/x-rar)
2017-07-17 08:33 EDT, owl337
no flags Details

  None (edit)
Description owl337 2017-07-17 08:33:50 EDT
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

How reproducible:

./sassc $POC

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);
(gdb) bt
#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.

Actual results:


Expected results:


Additional info:


This vulnerability is detected by team OWL337, with our custom fuzzer collAFL. Please contact ganshuitao@gmail.com   and chaoz@tsinghua.edu.cn if you need more info about the team, the tool or the vulnerability.
Comment 1 Aurelien Bompard 2017-07-18 09:24:05 EDT
Reported upstream as https://github.com/sass/libsass/issues/2446
Comment 2 Jan Kurik 2017-08-15 05:11:45 EDT
This bug appears to have been reported against 'rawhide' during the Fedora 27 development cycle.
Changing version to '27'.

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