From: Kees Cook <keescook@chromium.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Adam Zabrocki <pi3@pi3.com.pl>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S . Miller" <davem@davemloft.net>,
Solar Designer <solar@openwall.com>
Subject: Re: [PATCH] x86/kprobes: Fix optprobe to detect padding int3 correctly
Date: Fri, 11 Dec 2020 11:39:15 -0800 [thread overview]
Message-ID: <202012111139.948F2ECF1@keescook> (raw)
In-Reply-To: <160767025681.3880685.16021570341428835411.stgit@devnote2>
On Fri, Dec 11, 2020 at 04:04:17PM +0900, Masami Hiramatsu wrote:
> Fix optprobe to detect padding int3 correctly.
>
> Since commit 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP
> for linker fill bytes") changed the padding bytes between functions
> from nop to int3, when optprobe decodes a target function it finds
> int3 and gives up the jump optimization.
>
> Instead of giving up any int3 detection, this checks whether the
> rest of bytes to the end of the function are int3 or not. If all
> of those are int3, those come from the linker. In that case,
> optprobe continues jump optimization.
>
> Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes")
> Cc: stable@vger.kernel.org
> Reported-by: Adam Zabrocki <pi3@pi3.com.pl>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2020-12-11 21:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 7:04 [PATCH] x86/kprobes: Fix optprobe to detect padding int3 correctly Masami Hiramatsu
2020-12-11 14:49 ` Steven Rostedt
2020-12-11 19:39 ` Kees Cook [this message]
2020-12-11 20:04 ` Adam Zabrocki
2020-12-12 14:38 ` [tip: x86/urgent] x86/kprobes: Fix optprobe to detect INT3 padding correctly tip-bot2 for Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202012111139.948F2ECF1@keescook \
--to=keescook@chromium.org \
--cc=anil.s.keshavamurthy@intel.com \
--cc=bp@alien8.de \
--cc=davem@davemloft.net \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=mingo@redhat.com \
--cc=naveen.n.rao@linux.ibm.com \
--cc=pi3@pi3.com.pl \
--cc=rostedt@goodmis.org \
--cc=solar@openwall.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.