After verifying that vDSO getrandom does work, which ensures that the
RNG is initialized, test to see if it also works inside of a time
namespace. This is important to test, because the vvar pages get
swizzled around there. If the arch code isn't careful, the RNG will
appear uninitialized inside of a time namespace.
Because broken code makes the RNG appear uninitialized, test that
everything works by issuing a call to vgetrandom from a fork in a time
namespace, and use ptrace to ensure that the actual syscall getrandom
doesn't get called. If it doesn't get called, then the test succeeds.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
When building with clang, there's this warning:
vdso_test_getrandom.c:145:40: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
145 | static void *test_vdso_getrandom(void *)
| ^
vdso_test_getrandom.c:155:40: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
155 | static void *test_libc_getrandom(void *)
| ^
vdso_test_getrandom.c:165:43: warning: omitting the parameter name in a function definition is a C23 extension [-Wc23-extensions]
165 | static void *test_syscall_getrandom(void *)
Add the named ctx parameter to quash it.
Reported-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
vdso_test_correctness test fails on powerpc:
~ # ./vdso_test_correctness
...
[RUN] Testing clock_gettime for clock CLOCK_REALTIME_ALARM (8)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock CLOCK_BOOTTIME_ALARM (9)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock CLOCK_SGI_CYCLE (10)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
...
[RUN] Testing clock_gettime for clock invalid (-1)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock invalid (-2147483648)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock invalid (2147483647)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
On powerpc, a call to a VDSO function is not an ordinary C function
call. Unlike several architectures which returns a negative error code
in case of an error, powerpc sets CR[SO] and returns the error code
as a positive value.
Define and use a macro called VDSO_CALL() which takes a pointer
to the function to call, the number of arguments and the arguments.
Also update ABI vdso documentation to reflect this subtlety.
Provide a specific version of VDSO_CALL() for powerpc that negates
the error code on return when CR[SO] is set.
Fixes: c7e5789b24 ("kselftest: Move test_vdso to the vDSO test suite")
Fixes: 2e9a972566 ("selftests: vdso: Add a selftest for vDSO getcpu()")
Fixes: 693f5ca08c ("kselftest: Extend vDSO selftest")
Fixes: b2f1c3db28 ("kselftest: Extend vdso correctness test to clock_gettime64")
Fixes: 4920a2590e ("selftests/vDSO: add tests for vgetrandom")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
If the getrandom test compiles for an arch, don't exit fatally if the
actual cpu it's running on is unsupported.
Suggested-by: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Don't hard-code x86 specific names. Rather, use vdso_config definitions
to find the correct function matching the architecture.
Add random VDSO function names in names[][]. Remove the #ifdef
CONFIG_VDSO32, as having the name there all the time is harmless and
guaranties a steady index for following strings.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[Jason: add [6] to variable declaration rather than each usage site.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than using pthread_get/set_specific, just use gcc's __thread
annotation, which is noticeably faster and makes the code more obvious.
Also, just have one simplified struct called vgrnd, instead of trying to
split things up semantically. Those divisions were useful when this code
was split across several commit *messages*, but doesn't make as much
sense within a single file. This should make the code more clear and
provide a better example for implementers.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This adds two tests for vgetrandom. The first one, vdso_test_chacha,
simply checks that the assembly implementation of chacha20 matches that
of libsodium, a basic sanity check that should catch most errors. The
second, vdso_test_getrandom, is a full "libc-like" implementation of the
userspace side of vgetrandom() support. It's meant to be used also as
example code for libcs that might be integrating this.
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
