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 35AF4A461 for ; Mon, 28 Nov 2022 17:43:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDC30C433D6; Mon, 28 Nov 2022 17:43:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669657413; bh=erx4mekDg9iblF1wO5yq7GtbKAKHxTvYsT67M7AkDa8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cC+rb2w3koIgfZfu/VmpBcn++db5XWc6D6PSv6aJRnq6N3ZHlgEB5WaYJOOKOj8BT 8ONrwW0sGCcCsShOkg7GR7uyQ8owHqkUt4RFI1TXQIdsCg/6REA6BbMH/mDOrMOgEB 174CDxVpKEBVT1vgtKQk27dx/ZHswN9Nx5X1MFd3osgSW+YAWsxXuYvAYeURLML45u 0y4h4vAcJ2AuBXtdWy/eMSbMWUOyUMvyqY1yX3dsQIB8eKR9kAps36YqVhs/3gj23C BUdinbmouuAi/d/lmqefItzAt57ozpbV9Sf7q1KZvTqmjJdu8LI3SpZq4ECOle6pU0 MxcikUMGIWZYA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , kernel test robot , Jaroslav Kysela , Takashi Iwai , "Gustavo A. R. Silva" , alsa-devel@alsa-project.org, Takashi Iwai , Sasha Levin , nathan@kernel.org, ndesaulniers@google.com, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 4.9 4/5] ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event Date: Mon, 28 Nov 2022 12:43:22 -0500 Message-Id: <20221128174324.1443132-4-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221128174324.1443132-1-sashal@kernel.org> References: <20221128174324.1443132-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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