From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7AFA21373; Sat, 18 Jan 2025 20:21:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737231715; cv=none; b=BFOTDTR33CHxT6ruBBgWwXRw1rQHSWJth7BZcW7acIlQtefbJjgYL+KZSgGXNfAnwdip3NR9VjbNElAvOq8PcLvOJa1uFjuKm3nQCyu5TRMsQz7oETmbzxeBLM6tCxur6hPB2cvrGA56Izs3DxvCsvPRQAPbEHZcFu5B4N8PCwA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737231715; c=relaxed/simple; bh=q9qsMX/HkCYxQZH+8I2kWPXE6XRaUuOPM9zDN8q9VCc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YlCMWCn3/fhRt4dKMLBKRMVqMcqr/cZGy6augfkj/USH6LLHR8sW+uyT2w118K/s1aIy6OrMnxbW+gOSRT9Bm8Nabi2m8vB4VtDNpKuc55qHuHakKSjT14N/S7hxWcNWnfARE50WtKLlihLuNNCCoKw9GuY6xkE45EZtHAH3zD0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=h+pRX5Dv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="h+pRX5Dv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6730C4CED1; Sat, 18 Jan 2025 20:21:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737231715; bh=q9qsMX/HkCYxQZH+8I2kWPXE6XRaUuOPM9zDN8q9VCc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=h+pRX5DvroieuQST+ihh6zSupRiMWWPB9OSko7ZYMi6LM/IiItfx8J2Cz5wh1wh1F /uqh3bqBIoRDta5iMLj464zUvKLDvLUzl1fqyF742ZL7gxVT6tg7ujTXU17D13H6Hq Xn6T9vQXxlaY9nQVHkhrRM7Y9qnbGo7xWltLobvC26DxMfzoF6hMKg2cSPppu+DnE8 uo5T1aRE85jH4wVZ7+sgbgaV5qbKOhjZFXzsN47X6DYaxLuR302Kv50U83/YRSeXcF 8PHHRnz8VHErbVnaA0ywTYIzMrA5110hydni2Rw705ATBFwUYUlJ3NuMiTiyLZChx6 /OUy2wEmbe58w== Date: Sat, 18 Jan 2025 12:21:51 -0800 From: Kees Cook To: Eyal Birger Cc: luto@amacapital.net, wad@chromium.org, oleg@redhat.com, ldv@strace.io, mhiramat@kernel.org, andrii@kernel.org, jolsa@kernel.org, alexei.starovoitov@gmail.com, olsajiri@gmail.com, cyphar@cyphar.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, peterz@infradead.org, tglx@linutronix.de, bp@alien8.de, daniel@iogearbox.net, ast@kernel.org, andrii.nakryiko@gmail.com, rostedt@goodmis.org, rafi@rbk.io, shmulik.ladkani@gmail.com, bpf@vger.kernel.org, linux-api@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] seccomp: passthrough uretprobe systemcall without filtering Message-ID: <202501181212.4C515DA02@keescook> References: <20250117005539.325887-1-eyal.birger@gmail.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250117005539.325887-1-eyal.birger@gmail.com> On Thu, Jan 16, 2025 at 04:55:39PM -0800, Eyal Birger wrote: > Since uretprobe is a "kernel implementation detail" system call which is > not used by userspace application code directly, it is impractical and > there's very little point in forcing all userspace applications to > explicitly allow it in order to avoid crashing tracked processes. How is this any different from sigreturn, rt_sigreturn, or restart_syscall? These are all handled explicitly by userspace filters already, and I don't see why uretprobe should be any different. Docker has had plenty of experience with fixing their seccomp filters for new syscalls. For example, many times already a given libc will suddenly start using a new syscall when it sees its available, etc. Basically, this is a Docker issue, not a kernel issue. Seccomp is behaving correctly. I don't want to start making syscalls invisible without an extremely good reason. If _anything_ should be invisible, it is restart_syscall (which actually IS invisible under certain architectures). -Kees -- Kees Cook