vDSO, 32-bit time, and seccomp

Posted Aug 4, 2019 22:37 UTC (Sun) by marcH (subscriber, #57642)
In reply to: vDSO, 32-bit time, and seccomp by nix
Parent article: vDSO, 32-bit time, and seccomp

> the architecture-specific vDSO used the native clock_gettime() call on the system it was running on; that meant calling the 32-bit clock_gettime() on 32-bit kernels.

> the generic vDSO implementation naturally used clock_gettime64() as the fallback timekeeping system call on all architectures.

> During the 5.3 merge window, the x86 architecture switched over to the generic version,

If the version of clock_gettime() invoked was really the *internal* implementation detail it seemed to be, there wouldn't have been any issue. Just like firewalls, the seccomp approach doesn't seem to care about layers and abstractions. This basically "promotes" internal implementation details to API rank, right? What could possibly go wrong.

> Even if the kernel community avoids incompatible changes, a change in a library somewhere can invoke a new system call that a given seccomp() policy may frown upon.

Sounds like a "yes".