From mboxrd@z Thu Jan 1 00:00:00 1970 From: keescook@chromium.org (Kees Cook) Date: Mon, 22 Oct 2018 02:30:23 -0700 Subject: [PATCH] ARM: kprobes: Fix false positive with FORTIFY_SOURCE Message-ID: <20181022093023.GA8920@beast> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 size of the array pointed to by an address of a label is 4 bytes, which was tripping the runtime checks. Instead, we can just cast the label (as done with the size calculations earlier) to avoid the problem. Reported-by: William Cohen Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions") Cc: stable at vger.kernel.org Signed-off-by: Kees Cook --- arch/arm/probes/kprobes/opt-arm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index b2aa9b32bff2..2c118a6ab358 100644 --- a/arch/arm/probes/kprobes/opt-arm.c +++ b/arch/arm/probes/kprobes/opt-arm.c @@ -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. */ -- 2.17.1 -- Kees Cook Pixel Security