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Message-ID: <20201030130713.GB6532@zn.tnic>
Date: Fri, 30 Oct 2020 14:07:13 +0100
From: Borislav Petkov <bp@...en8.de>
To: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Andy Lutomirski <luto@...nel.org>, x86-ml <x86@...nel.org>,
Joerg Roedel <jroedel@...e.de>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: [RFC] Have insn decoder functions return success/failure
On Fri, Oct 30, 2020 at 10:24:53AM +0900, Masami Hiramatsu wrote:
> What's the objdump say here?
The expected "bad":
0: c5 ec 95 (bad)
3: b2 02 mov $0x2,%dl
5: bd 4b c8 a8 36 mov $0x36a8c84b,%ebp
a: b2 c5 mov $0xc5,%dl
c: c0 df 13 rcr $0x13,%bh
> Yes, in this case, we would better to handle it as an undecodable input
> instead of access violation in insn_sanity.
Ok, good. I've got the hunk below now and it does the right thing. The
whole patch has become huuge now, lemme split it finally. :)
Thx.
---
diff --git a/arch/x86/tools/insn_sanity.c b/arch/x86/tools/insn_sanity.c
index 185ceba9d289..f20765beec9c 100644
--- a/arch/x86/tools/insn_sanity.c
+++ b/arch/x86/tools/insn_sanity.c
@@ -222,8 +224,8 @@ static void parse_args(int argc, char **argv)
int main(int argc, char **argv)
{
+ int insns = 0, ret;
struct insn insn;
- int insns = 0;
int errors = 0;
unsigned long i;
unsigned char insn_buff[MAX_INSN_SIZE * 2];
@@ -241,15 +243,15 @@ int main(int argc, char **argv)
continue;
/* Decode an instruction */
- insn_init(&insn, insn_buff, sizeof(insn_buff), x86_64);
- insn_get_length(&insn);
+ ret = insn_decode(&insn, insn_buff, sizeof(insn_buff),
+ x86_64 ? INSN_MODE_64 : INSN_MODE_32);
if (insn.next_byte <= insn.kaddr ||
insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
/* Access out-of-range memory */
dump_stream(stderr, "Error: Found an access violation", i, insn_buff, &insn);
errors++;
- } else if (verbose && !insn_complete(&insn))
+ } else if (verbose && ret < 0)
dump_stream(stdout, "Info: Found an undecodable input", i, insn_buff, &insn);
else if (verbose >= 2)
dump_insn(stdout, &insn);
--
Regards/Gruss,
Boris.
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