From: Peter Zijlstra <peterz@infradead.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Elly I. Esparza" <ellyesparza8@gmail.com>,
linux-kernel@vger.kernel.org, luto@kernel.org,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
Naveen N Rao <naveen@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
linux-trace-kernel@vger.kernel.org, Kees Cook <kees@kernel.org>
Subject: Re: [PATCH 1/2] x86: Prevent syscall hooking
Date: Wed, 18 Feb 2026 16:32:44 +0100 [thread overview]
Message-ID: <20260218153244.GG1282955@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <0c5396b5-f084-4ade-adc9-029037031eea@intel.com>
On Wed, Feb 18, 2026 at 07:18:25AM -0800, Dave Hansen wrote:
> ... adding kprobes folks and Kees to cc
>
> On 2/18/26 06:47, Elly I. Esparza wrote:
> > Kprobes can be used by rootkits to find the address of x64_sys_call(),
> > x32_sys_call() and ia32_sys_call(). This in turn allows for the rootkits
> > to find an specific syscall handler and hook it.
> >
> > Add x64_sys_call(), x32_sys_call() and ia32_sys_call() to the kprobes
> > blacklist.
> I'm an occasional, but not super regular kprobes user. Is this going to
> hurt folks who are legitimately probing the syscall dispatch functions?
>
> I'm a bit worried that the rootkits will just move on to something else
> and this will become a never ending game of whack-a-mole where half the
> kernel needs NOKPROBE_SYMBOL(). ;)
So I really think this should be noinstr; pretty much all the code here
is noinstr already, so why not include the syscall dispatch.
Better still, noinstr ensures the spectre-v1 mitigation actually works.
next prev parent reply other threads:[~2026-02-18 15:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260218144735.24307-1-ellyesparza8@gmail.com>
2026-02-18 15:18 ` [PATCH 1/2] x86: Prevent syscall hooking Dave Hansen
2026-02-18 15:32 ` Peter Zijlstra [this message]
2026-02-19 21:51 ` H. Peter Anvin
2026-02-18 15:52 ` Steven Rostedt
2026-02-18 16:58 ` ellyndra
2026-02-19 18:45 ` Kees Cook
2026-02-20 2:45 ` Masami Hiramatsu
2026-02-20 17:04 ` Christoph Hellwig
2026-02-20 17:12 ` Steven Rostedt
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