thodg/libgit2/tests

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    Commit

  • Hash : a9f1ca09
    Author : Patrick Steinhardt
    Date : 2018-08-09T11:01:00 

    smart_pkt: fix buffer overflow when parsing "ok" packets

There are two different buffer overflows present when parsing "ok"
packets. First, we never verify whether the line already ends after
"ok", but directly go ahead and also try to skip the expected space
after "ok". Second, we then go ahead and use `strchr` to scan for the
terminating newline character. But in case where the line isn't
terminated correctly, this can overflow the line buffer.

Fix the issues by using `git__prefixncmp` to check for the "ok " prefix
and only checking for a trailing '\n' instead of using `memchr`. This
also fixes the issue of us always requiring a trailing '\n'.

Reported by oss-fuzz, issue 9749:

Crash Type: Heap-buffer-overflow READ {*}
Crash Address: 0x6310000389c0
Crash State:
  ok_pkt
  git_pkt_parse_line
  git_smart__store_refs

Sanitizer: address (ASAN)

  • README.md

  • Writing Clar tests for libgit2

    For information on the Clar testing framework and a detailed introduction please visit:

    https://github.com/vmg/clar

    • Write your modules and tests. Use good, meaningful names.

    • Make sure you actually build the tests by setting: 

        cmake -DBUILD_CLAR=ON build/

    • Test: 

        ./build/libgit2_clar

    • Make sure everything is fine.

    • Send your pull request. That’s it.

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