From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 9AD171E1E0C; Wed, 30 Apr 2025 19:03:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746039829; cv=none; b=mckWoyLrzDWwL3UzDUuUOT9BoA6MY36XsS2rbWAoDO1dFxGltYQtmnix9shdpANH+/avjTGA3Vq3+H5Yn2wFZqsAvUCzIhaE48crYbPG+/F17jqwVKIBmQs3j323sEMFK2XsEsUJCNwIaODHl1yOPHZ4NvIS4D97X8gD/08frgk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746039829; c=relaxed/simple; bh=7PlAl5GrsC56vg7MmjldnKQvgVZMamAl/DYAPIwwgdI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qcOjSQTGqRrhytjBOHSRXVNitLD17bq8EimyzydqjhfyTlYqvJBLKbQK/+bbsuPbpZhXKVn0YWctAnwRij54cBNNAXGndzBKQ+Pe/TiKA+H2pBFnUgjuVfWzhrE1bGewYOIUxkNunLA7D5bBXvb+DxBqkEnmuTI6Uvgv90MR7ww= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=b6yvpT8q; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="b6yvpT8q" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=4eoS1/JAdmLl2q5sTbw4/3ulNP/0LFxVs4HLw+j+3nY=; b=b6yvpT8qjSWgIETd+HWyaFKyRU GkQfulCHdD95orhMFtJowoz4ejB+4yvZxu2zBb4bVIHhjv9f5nn5i8SzGBJLDwNafuRLu0LSo4blF 07ul778ewuftqGYQSK8vdZPG1Q+2YqukAPT+MRPAbvjUZkT+Nl7cpsjV8tv7eB7q0VdkQKq2bCAlk d2R/TjPnNt6Dhv1/XyvCjWEMPzbYy2U5yq7MzioVwr2XU++22Z4G7qirbegL0HwTtcbfjwGcIap62 53atdozDyM9o6OiLBpAWvkWHKU7J9yski8Q8v9W831s2oNjSk7GgglmOKHRum1Qg0r0U8F8xwhHoN m6mmdaJw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.1 #2 (Red Hat Linux)) id 1uACiP-0000000DpFF-3wgw; Wed, 30 Apr 2025 19:03:30 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 30285300642; Wed, 30 Apr 2025 21:03:29 +0200 (CEST) Date: Wed, 30 Apr 2025 21:03:28 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: x86@kernel.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, ardb@kernel.org, kees@kernel.org, Arnd Bergmann , gregkh@linuxfoundation.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, samitolvanen@google.com, ojeda@kernel.org Subject: Re: [PATCH v2 13/13] objtool: Validate kCFI calls Message-ID: <20250430190328.GO4439@noisy.programming.kicks-ass.net> References: <20250430110734.392235199@infradead.org> <20250430112350.443414861@infradead.org> Precedence: bulk X-Mailing-List: kvm@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: On Wed, Apr 30, 2025 at 08:59:53AM -0700, Josh Poimboeuf wrote: > On Wed, Apr 30, 2025 at 01:07:47PM +0200, Peter Zijlstra wrote: > > + case ANNOTYPE_NOCFI: > > + sym = insn->sym; > > + if (!sym) { > > + ERROR_INSN(insn, "dodgy NOCFI annotation"); > > + break; > > return -1; Oh right. > > + /* > > + * kCFI call sites look like: > > + * > > + * movl $(-0x12345678), %r10d > > + * addl -4(%r11), %r10d > > + * jz 1f > > + * ud2 > > + * 1: cs call __x86_indirect_thunk_r11 > > + * > > + * Verify all indirect calls are kCFI adorned by checking for the > > + * UD2. Notably, doing __nocfi calls to regular (cfi) functions is > > + * broken. > > + */ > > + list_for_each_entry(insn, &file->retpoline_call_list, call_node) { > > + struct symbol *sym = insn->sym; > > + > > + if (sym && sym->type == STT_FUNC && !sym->nocfi) { > > + struct instruction *prev = > > + prev_insn_same_sym(file, insn); > > + > > + if (!prev || prev->type != INSN_BUG) { > > + WARN_INSN(insn, "no-cfi indirect call!"); > > + warnings++; > > Do we not care about indirect calls from !STT_FUNC? Let me try, see what happens.