From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6BC7C41513 for ; Mon, 27 May 2024 16:11:41 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=bEyrSrhm; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Vp0pl01Pfz99ZG for ; Tue, 28 May 2024 02:05:03 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=bEyrSrhm; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=sashal@kernel.org; receiver=lists.ozlabs.org) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Vp0hb1z7Xz89Qs for ; Tue, 28 May 2024 01:59:43 +1000 (AEST) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id EB34D61B1C; Mon, 27 May 2024 15:59:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5399BC4AF0B; Mon, 27 May 2024 15:59:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716825581; bh=DjAs8dmTmQ1x9EQebS1fjcTYhz0yBUAm+9fuL3XtfuA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bEyrSrhmagK59fAw7xNGrD82wwqi5eYa7SAAhfYcd0AORe9UPa3wrs/nW+GqCBFGU 2SDovz75dRn3S5PSTBKxeWPftaADMaffrDqXdinojYMWF6c+vrymNIvfBoYDxmiv66 IcscW54+FpEcPnCRRL+uRPHfS2Q3L7ZSjdwxXGAsaoClgWQRM9leHXxCveedTFZtXR ah8MIFadhj+vkMv3AhhVulNWT9cRFNaf8mZZ1c9X+NrCiNxJ4VNHt9LHgRxdnRWlbO RI6J46U+31O6ySdo+JUNBwv1PJtVqdSJ8V060eF/7CMXmrMGRXT45sBoFyZ4TSeTEW JUqwIZPbfKlZQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 2/3] powerpc/pseries: Enforce hcall result buffer validity and size Date: Mon, 27 May 2024 11:59:17 -0400 Message-ID: <20240527155925.3866466-2-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240527155925.3866466-1-sashal@kernel.org> References: <20240527155925.3866466-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.277 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nathan Lynch , Sasha Levin , llvm@lists.linux.dev, sshegde@linux.ibm.com, nathan@kernel.org, kconsul@linux.vnet.ibm.com, jniethe5@gmail.com, vaibhav@linux.ibm.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Nathan Lynch [ Upstream commit ff2e185cf73df480ec69675936c4ee75a445c3e4 ] plpar_hcall(), plpar_hcall9(), and related functions expect callers to provide valid result buffers of certain minimum size. Currently this is communicated only through comments in the code and the compiler has no idea. For example, if I write a bug like this: long retbuf[PLPAR_HCALL_BUFSIZE]; // should be PLPAR_HCALL9_BUFSIZE plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, ...); This compiles with no diagnostics emitted, but likely results in stack corruption at runtime when plpar_hcall9() stores results past the end of the array. (To be clear this is a contrived example and I have not found a real instance yet.) To make this class of error less likely, we can use explicitly-sized array parameters instead of pointers in the declarations for the hcall APIs. When compiled with -Warray-bounds[1], the code above now provokes a diagnostic like this: error: array argument is too small; is of size 32, callee requires at least 72 [-Werror,-Warray-bounds] 60 | plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, | ^ ~~~~~~ [1] Enabled for LLVM builds but not GCC for now. See commit 0da6e5fd6c37 ("gcc: disable '-Warray-bounds' for gcc-13 too") and related changes. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://msgid.link/20240408-pseries-hvcall-retbuf-v1-1-ebc73d7253cf@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/include/asm/hvcall.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 11112023e327d..344330b17376f 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -403,7 +403,7 @@ long plpar_hcall_norets(unsigned long opcode, ...); * Used for all but the craziest of phyp interfaces (see plpar_hcall9) */ #define PLPAR_HCALL_BUFSIZE 4 -long plpar_hcall(unsigned long opcode, unsigned long *retbuf, ...); +long plpar_hcall(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL_BUFSIZE], ...); /** * plpar_hcall_raw: - Make a hypervisor call without calculating hcall stats @@ -417,7 +417,7 @@ long plpar_hcall(unsigned long opcode, unsigned long *retbuf, ...); * plpar_hcall, but plpar_hcall_raw works in real mode and does not * calculate hypervisor call statistics. */ -long plpar_hcall_raw(unsigned long opcode, unsigned long *retbuf, ...); +long plpar_hcall_raw(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL_BUFSIZE], ...); /** * plpar_hcall9: - Make a pseries hypervisor call with up to 9 return arguments @@ -428,8 +428,8 @@ long plpar_hcall_raw(unsigned long opcode, unsigned long *retbuf, ...); * PLPAR_HCALL9_BUFSIZE to size the return argument buffer. */ #define PLPAR_HCALL9_BUFSIZE 9 -long plpar_hcall9(unsigned long opcode, unsigned long *retbuf, ...); -long plpar_hcall9_raw(unsigned long opcode, unsigned long *retbuf, ...); +long plpar_hcall9(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL9_BUFSIZE], ...); +long plpar_hcall9_raw(unsigned long opcode, unsigned long retbuf[static PLPAR_HCALL9_BUFSIZE], ...); struct hvcall_mpp_data { unsigned long entitled_mem; -- 2.43.0