The configuration in `DefaultOptions.qll` assumed that a call to any
top-level function named `error` would exit the program. This is not
true.
The assumption was probably about `error(3)`, which is a GNU extension.
It only exits if its first argument it not 0. Furthermore, projects such
as openssh may define their own function named `error` with different
behaviour. Because the GNU `error` function is non-standard, it's
perfectly fine to shadow it with a project-specific definition.
This change removes two FPs from `PointlessComparison.qll` on
https://github.com/openssh/openssh-portable.
A PR check was failing because this query was enabled on LGTM but had no
qhelp. I'm removing the `@precision` for now to take it off LGTM, and
then we can add it back when it has qhelp, tests, and change note.
Thanks to Sam Lanning (@samlanning) and Robert Marsh for taking the time to help
to make it possible. In fact, it was Robert Marsh who effectively
wrote the query and figured out that __builtin_alloca should be
used to also take functions like strdupa into account. I just
filled out the metadata :-)
Before this change, all the cached predicates in `IRGuards.qll` were in
separate cached stages, resulting in recomputation of most of the
library for each stage. This change groups the cached predicates in two
cached classes. A better grouping may be possible, but this grouping was
easy to do and seems to solve the problem.
Before this change, the `IRGuards` library accounted for five cached
stages when using the `RangeAnalysis` library. After this change, it
only accounts for one.
This new query is not written because it's the most interesting query we
could write but because it's an IR-based query whose results are easy to
verify.
After a `queries.xml` was added to the test directory,
`Container.getRelativePath` now considers source files to be relative to
the `cpp/test` directory rather than the directory of the `*.ql*` file.
This caused some benign test output changes, and it also caused an
unwanted alert for `test3.c:14` to appear in
`cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/IntegerOverflowTainted.expected`.
This alert came about because `inSystemMacroExpansion` holds for files
that don't have a relative path, but the pretend system header in
`../system_header` now does have a relative path because it's below the
`cpp/test` directory. The fix is to add another `queries.xml` just for
the directory with the affected test.
