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 739F1A461 for ; Mon, 28 Nov 2022 17:42:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C749EC433C1; Mon, 28 Nov 2022 17:42:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669657373; bh=tWi8m0zIJyvdgVCG88lBeVWG25YXSJvsKgl/s+TMVZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S5F2Ht4ycCc6MSCQtsKrVbmCkbH0oAiNZT2MNItydEffHu2mviFnoboHPNkqPC+A2 I8xBXrzUIcHFycmuyCMCU8S5peItfacq7mV1IfudihOrmI3twrLDoQzcjhaqI6kZDT 8BceOjIac/HK0xMxAMETOVIRNQ4RNX/bXkQis09S+ecP8L9aK6TG6lUqxvdcoQmlr8 ogJcfTYoFsaQz8M9SIOqnnvs5Gyn6l224iaC3qXO74qIUXEPdY7IyDSEPGhEUq+Yam uAZEzc3WhMbZdjBJNlmqAE93NuMOvBaOXeQ3A0Yu9k7mIn0jKMdQszWN3n95KphXeO Ohvf1HHXzkQ/A== 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 4.19 07/12] ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event Date: Mon, 28 Nov 2022 12:42:30 -0500 Message-Id: <20221128174235.1442841-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221128174235.1442841-1-sashal@kernel.org> References: <20221128174235.1442841-1-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 5b0388202bac..ac854beb8347 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