From mboxrd@z Thu Jan 1 00:00:00 1970 From: mhiramat@kernel.org (Masami Hiramatsu) Date: Thu, 1 Nov 2018 23:41:02 +0900 Subject: [PATCH] ARM: kprobes: Fix false positive with FORTIFY_SOURCE In-Reply-To: References: <20181022093023.GA8920@beast> Message-ID: <20181101234102.5fd16894fefffe18fccd6999@kernel.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 30 Oct 2018 13:40:27 -0400 William Cohen wrote: > On 10/22/18 5:30 AM, 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 > > --- > > 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. */ > > > > The patch fixes the issue for kretprobes. It looks good to me. This looks good to me too. Thank you for finding and fixing it :) Acked-by: Masami Hiramatsu Thanks! > > Thanks, > > -Will -- Masami Hiramatsu