Commit d88d59b6 authored Aug 19, 2020 by Thomas Gleixner

core/entry: Respect syscall number rewrites



The transcript of the x86 entry code to the generic version failed to
reload the syscall number from ptregs after ptrace and seccomp have run,
which both can modify the syscall number in ptregs. It returns the original
syscall number instead which is obviously not the right thing to do.

Reload the syscall number to fix that.

Fixes: 142781e1 ("entry: Provide generic syscall entry functionality")
Reported-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kyle Huey <me@kylehuey.com>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/87blj6ifo8.fsf@nanos.tec.linutronix.de

parent 9123e3a7

kernel/entry/common.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -65,7 +65,8 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall,

		syscall_enter_audit(regs, syscall);

		return ret ? : syscall;
		/* The above might have changed the syscall number */
		return ret ? : syscall_get_nr(current, regs);
		}

		noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)

Admin message