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fget_cap() tries to do a cheaper snapshot of a file descriptor without holding the file descriptor lock. This snapshot does not do a deep copy of the ioctls capability array, but instead uses a different return value to inform the caller to retry the copy with the lock held. However, filecaps_copy() was returning 1 to indicate that a retry was required, and fget_cap() was checking for 0 (actually '!filecaps_copy()'). As a result, fget_cap() did not do a deep copy of the ioctls array and just reused the original pointer. This cause multiple file descriptor entries to think they owned the same pointer and eventually resulted in duplicate frees. The only code path that I'm aware of that triggers this is to create a listen socket that has a restricted list of ioctls and then call accept() which calls fget_cap() with a valid filecaps structure from getsock_cap(). To fix, change the return value of filecaps_copy() to return true if it succeeds in copying the caps and false if it fails because the lock is required. I find this more intuitive than fixing the caller in this case. While here, change the return type from 'int' to 'bool'. Finally, make filecaps_copy() more robust in the failure case by not copying any of the source filecaps structure over. This avoids the possibility of leaking a pointer into a structure if a similar future caller doesn't properly handle the return value from filecaps_copy() at the expense of one more branch. I also added a test case that panics before this change and now passes. Reviewed by: kib Discussed with: mjg (not a fan of the extra branch) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D15047 |
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etc | ||
freebsd_test_suite | ||
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Kyuafile | ||
Makefile | ||
Makefile.depend | ||
Makefile.inc0 | ||
README |
src/tests: The FreeBSD test suite ================================= To run the FreeBSD test suite: (1) Make sure that kyua is installed: pkg install kyua (2) To run the tests: kyua test -k /usr/tests/Kyuafile (3) To see the test results: kyua report For further information on using the test suite, read tests(7): man tests Description of FreeBSD test suite ================================= The build of the test suite is organized in the following manner: * The build of all test artifacts is protected by the MK_TESTS knob. The user can disable these with the WITHOUT_TESTS setting in src.conf(5). * The goal for /usr/tests/ (the installed test programs) is to follow the same hierarchy as /usr/src/ wherever possible, which in turn drives several of the design decisions described below. This simplifies the discoverability of tests. We want a mapping such as: /usr/src/bin/cp/ -> /usr/tests/bin/cp/ /usr/src/lib/libc/ -> /usr/tests/lib/libc/ /usr/src/usr.bin/cut/ -> /usr/tests/usr.bin/cut/ ... and many more ... * Test programs for specific utilities and libraries are located next to the source code of such programs. For example, the tests for the src/lib/libcrypt/ library live in src/lib/libcrypt/tests/. The tests/ subdirectory is optional and should, in general, be avoided. * The src/tests/ hierarchy (this directory) provides generic test infrastructure and glue code to join all test programs together into a single test suite definition. * The src/tests/ hierarchy also includes cross-functional test programs: i.e. test programs that cover more than a single utility or library and thus don't fit anywhere else in the tree. Consider this to follow the same rationale as src/share/man/: this directory contains generic manual pages while the manual pages that are specific to individual tools or libraries live next to the source code. In order to keep the src/tests/ hierarchy decoupled from the actual test programs being installed --which is a worthy goal because it simplifies the addition of new test programs and simplifies the maintenance of the tree-- the top-level Kyuafile does not know which subdirectories may exist upfront. Instead, such Kyuafile automatically detects, at run-time, which */Kyuafile files exist and uses those directly. Similarly, every directory in src/ that wants to install a Kyuafile to just recurse into other subdirectories reuses this Kyuafile with auto-discovery features. As an example, take a look at src/lib/tests/ whose sole purpose is to install a Kyuafile into /usr/tests/lib/. The goal in this specific case is for /usr/tests/lib/ to be generated entirely from src/lib/. -- $FreeBSD$