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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8667C4332F for ; Mon, 12 Dec 2022 13:55:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233295AbiLLNzX (ORCPT ); Mon, 12 Dec 2022 08:55:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233283AbiLLNzD (ORCPT ); Mon, 12 Dec 2022 08:55:03 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BA2514D37 for ; Mon, 12 Dec 2022 05:54:53 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id AD5B9610A5 for ; Mon, 12 Dec 2022 13:54:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D58EC433D2; Mon, 12 Dec 2022 13:54:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670853292; bh=erx4mekDg9iblF1wO5yq7GtbKAKHxTvYsT67M7AkDa8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8TT0nFufF20H9xlTndK7Fz/MIHmTjUiohkTvwmNrlZyVm1B97pzBNWiiUnSHDfUG SeOsrBm3bipHrN1N4SfG8GUdEn3olwGVBIZoZoqsqAPQqZR3UPB8dhQuQDePZN+IpU XiSmkR83aTiV+WekPgBy7tUoE2nNDvHEEMXRzhiM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , Jaroslav Kysela , Takashi Iwai , "Gustavo A. R. Silva" , alsa-devel@alsa-project.org, Kees Cook , Takashi Iwai , Sasha Levin Subject: [PATCH 4.9 04/31] ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event Date: Mon, 12 Dec 2022 14:19:22 +0100 Message-Id: <20221212130910.180549087@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221212130909.943483205@linuxfoundation.org> References: <20221212130909.943483205@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kees Cook [ Upstream commit 05530ef7cf7c7d700f6753f058999b1b5099a026 ] With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. seq_copy_in_user() and seq_copy_in_kernel() did not have prototypes matching snd_seq_dump_func_t. Adjust this and remove the casts. There are not resulting binary output differences. This was found as a result of Clang's new -Wcast-function-type-strict flag, which is more sensitive than the simpler -Wcast-function-type, which only checks for type width mismatches. Reported-by: kernel test robot Link: https://lore.kernel.org/lkml/202211041527.HD8TLSE1-lkp@intel.com Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: "Gustavo A. R. Silva" Cc: alsa-devel@alsa-project.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221118232346.never.380-kees@kernel.org Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/seq/seq_memory.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c index 4c8cbcd89887..42f4aa841051 100644 --- a/sound/core/seq/seq_memory.c +++ b/sound/core/seq/seq_memory.c @@ -126,15 +126,19 @@ EXPORT_SYMBOL(snd_seq_dump_var_event); * expand the variable length event to linear buffer space. */ -static int seq_copy_in_kernel(char **bufptr, const void *src, int size) +static int seq_copy_in_kernel(void *ptr, void *src, int size) { + char **bufptr = ptr; + memcpy(*bufptr, src, size); *bufptr += size; return 0; } -static int seq_copy_in_user(char __user **bufptr, const void *src, int size) +static int seq_copy_in_user(void *ptr, void *src, int size) { + char __user **bufptr = ptr; + if (copy_to_user(*bufptr, src, size)) return -EFAULT; *bufptr += size; @@ -163,8 +167,7 @@ int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char return newlen; } err = snd_seq_dump_var_event(event, - in_kernel ? (snd_seq_dump_func_t)seq_copy_in_kernel : - (snd_seq_dump_func_t)seq_copy_in_user, + in_kernel ? seq_copy_in_kernel : seq_copy_in_user, &buf); return err < 0 ? err : newlen; } -- 2.35.1