Commit e46daee5 authored Oct 30, 2018 by Kees Cook Committed by Russell King Nov 08, 2018

ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE

The arm compiler internally interprets an inline assembly label
as an unsigned long value, not a pointer. As a result, under
CONFIG_FORTIFY_SOURCE, the address of a label has a size of 4 bytes,
which was tripping the runtime checks. Instead, we can just cast the label
(as done with the size calculations earlier).

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1639397



Reported-by: William Cohen <wcohen@redhat.com>
Fixes: 6974f0c4 ("include/linux/string.h: add the option of fortified string.h functions")
Cc: stable@vger.kernel.org
Acked-by: Laura Abbott <labbott@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: William Cohen <wcohen@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

parent 65102238

arch/arm/probes/kprobes/opt-arm.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -247,7 +247,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe op, struct kprobe or
		}

		/* Copy arch-dep-instance from template. */
		memcpy(code, &optprobe_template_entry,
		memcpy(code, (unsigned char *)optprobe_template_entry,
		TMPL_END_IDX * sizeof(kprobe_opcode_t));

		/* Adjust buffer according to instruction. */