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2 commits

Author SHA1 Message Date
Sergei Trofimovich b74962c92b src/libexpr/search-path.cc: avoid out-of-bounds read on string_view
Without the change build with `-D_GLIBCXX_ASSERTIONS` exposes testsuite
assertion:

    $ gdb src/libexpr/tests/libnixexpr-tests
    Reading symbols from src/libexpr/tests/libnixexpr-tests...
    (gdb) break __glibcxx_assert_fail
    (gdb) run
    (gdb) bt
    in std::__glibcxx_assert_fail(char const*, int, char const*, char const*)@plt () from /mnt/archive/big/git/nix/src/libexpr/libnixexpr.so
    in std::basic_string_view<char, std::char_traits<char> >::operator[] (this=0x7fffffff56c0, __pos=4)
        at /nix/store/r74fw2j8rx5idb0w8s1s6ynwwgs0qmh9-gcc-14.0.0/include/c++/14.0.0/string_view:258
    in nix::SearchPath::Prefix::suffixIfPotentialMatch (this=0x7fffffff5780, path=...) at src/libexpr/search-path.cc:15
    in nix::SearchPathElem_suffixIfPotentialMatch_partialPrefix_Test::TestBody (this=0x555555a17540) at src/libexpr/tests/search-path.cc:62

As string sizes are usigned types `(a - b) > 0` effectively means
`a != b`. While the intention should be `a > b`.

The change fixes test suite pass.
2023-08-14 22:07:37 +01:00
John Ericson be518e73ae Clean up SearchPath
- Better types

- Own header / C++ file pair

- Test factored out methods

- Pass parsed thing around more than strings

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
2023-07-09 23:22:22 -04:00