Commit c60a32ea authored Jul 30, 2019 by Thomas Gleixner

lib/vdso/32: Provide legacy syscall fallbacks

To address the regression which causes seccomp to deny applications the
access to clock_gettime64() and clock_getres64() syscalls because they
are not enabled in the existing filters.

That trips over the fact that 32bit VDSOs use the new clock_gettime64() and
clock_getres64() syscalls in the fallback path.

Add a conditional to invoke the 32bit legacy fallback syscalls instead of
the new 64bit variants. The conditional can go away once all architectures
are converted.

Fixes: 00b26474 ("lib/vdso: Provide generic VDSO implementation")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907301134470.1738@nanos.tec.linutronix.de

parent 502a590a

lib/vdso/gettimeofday.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -125,14 +125,18 @@ __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)

		ret = __cvdso_clock_gettime_common(clock, &ts);

		#ifdef VDSO_HAS_32BIT_FALLBACK
		if (unlikely(ret))
		return clock_gettime32_fallback(clock, res);
		#else
		if (unlikely(ret))
		ret = clock_gettime_fallback(clock, &ts);
		#endif

		if (likely(!ret)) {
		res->tv_sec = ts.tv_sec;
		res->tv_nsec = ts.tv_nsec;
		}

		return ret;
		}

		@@ -232,8 +236,14 @@ __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
		int ret;

		ret = __cvdso_clock_getres_common(clock, &ts);

		#ifdef VDSO_HAS_32BIT_FALLBACK
		if (unlikely(ret))
		return clock_getres32_fallback(clock, res);
		#else
		if (unlikely(ret))
		ret = clock_getres_fallback(clock, &ts);
		#endif

		if (likely(!ret)) {
		res->tv_sec = ts.tv_sec;