From mboxrd@z Thu Jan 1 00:00:00 1970 From: mhiramat@kernel.org (Masami Hiramatsu) Date: Tue, 23 Oct 2018 10:06:04 +0900 Subject: [PATCH] ARM: kprobes: Fix false positive with FORTIFY_SOURCE In-Reply-To: <20181022093023.GA8920@beast> References: <20181022093023.GA8920@beast> Message-ID: <20181023100604.ea7a1a9b5c1c8904aab1b36b@kernel.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 22 Oct 2018 02:30:23 -0700 Kees Cook wrote: > 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 Good catch! This looks good to me. Acked-by: Masami Hiramatsu Thank you, > --- > 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 -- Masami Hiramatsu