From: Peter Zijlstra <peterz@infradead.org>
To: Ian Rogers <irogers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-kernel@vger.kernel.org,
Adrian Hunter <adrian.hunter@intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Numfor Mbiziwo-Tiapo <nums@google.com>
Subject: Re: [PATCH 1/2] x86/insn: Fix some potential undefined behavior.
Date: Thu, 15 Oct 2020 12:05:22 +0200 [thread overview]
Message-ID: <20201015100522.GZ2611@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201015062148.1437894-1-irogers@google.com>
On Wed, Oct 14, 2020 at 11:21:47PM -0700, Ian Rogers wrote:
> From: Numfor Mbiziwo-Tiapo <nums@google.com>
>
> If insn_init is given a NULL kaddr and 0 buflen then validate_next will
> perform arithmetic on NULL, add a guard to avoid this.
How is this a problem? NULL is (void *)0, you can do arithmetic on that
just fine.
Is UBSAN taking drugs again?
> Don't perform unaligned loads in __get_next and __peek_nbyte_next as
> these are forms of undefined behavior.
Fair enough; that could actually be a problem when we start to
cross-build this stuff. A RISC hosted version of the x86 decoder could
indeed trip this up.
But also, these are two changes in one patch.
prev parent reply other threads:[~2020-10-15 10:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 6:21 [PATCH 1/2] x86/insn: Fix some potential undefined behavior Ian Rogers
2020-10-15 6:21 ` [PATCH 2/2] tools/x86: " Ian Rogers
2020-10-15 8:31 ` Masami Hiramatsu
2020-10-15 8:01 ` [PATCH 1/2] x86/insn: " Ingo Molnar
2020-10-15 8:29 ` Masami Hiramatsu
2020-10-15 10:05 ` Peter Zijlstra [this message]
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