From patchwork Tue Mar 5 17:24:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 13582791 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 A9BCD17582; Tue, 5 Mar 2024 17:24:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709659498; cv=none; b=JfCHO1CLAQiKAMd+BOr5honlFPUvTBgTNgmJAsOUBYnUlXTGmxEJcOE68DENZ2HzQhnb7kKJhOypRbMhLSbzLH0HpV/GhmSyDqT7nSp7Zm9zxb9XVprPcRDY2gtBeUBmF7AkhfdG5q6WHkVAixk2rcOtQslsW0fsZn8hGCd90fU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709659498; c=relaxed/simple; bh=0lwIjheUVVinIAmrLyBNdgK66HWaAqekBzSfCyt9IXA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZpcOet2AJhSn5nUxdxY4pFbLo01bUGNgwb0ejp5So9KVjnnsYTSQ2cYjQXmcubz5PW9MPb7I7Bk3GFat0lOeTD1G8Oo1DnqKmxBncZf5m8dg+1WBT4Ds9IEIkBgK6uGDQWsJ4loW0b9TV5j480iyczy8whu+zJqqgnH07y6gV9Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Z903NSju; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Z903NSju" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 427CCC433F1; Tue, 5 Mar 2024 17:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709659498; bh=0lwIjheUVVinIAmrLyBNdgK66HWaAqekBzSfCyt9IXA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z903NSjuRS54CjitvIUAHCtyiTeYD9kpF16xaR6iCL0pBoY7G2j1sdFwYrxw9llc3 vAneSCEfELCgq9mk8dxSj/AJSDfxpBXh9Of7zHDuhZgbHAJVxkAPbYfl++P3FK7PFB ep2fLKsOtkra6ll9CtSwoHrap4qqibhT7NhvSAsbvhhSAbPu4D6lEVM+8v8wbrxjeD J+RXr4lNozZ6SEp6K5qX54J4yelJI2ZD5Q14HEPyj3rVU/e1/PvAXhhSsVP7b+Ay2T fI6tLHe/LNMDZMrS3K4cUImbIQPtrpmQ8XFYMUZCyUphwI5obMSq0gHxYRJAXyh1z/ gC/rlOZXKIS3Q== Date: Tue, 5 Mar 2024 11:24:55 -0600 From: "Gustavo A. R. Silva" To: Takashi Sakamoto , Clemens Ladisch , Jaroslav Kysela , Takashi Iwai Cc: Kees Cook , linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org, alsa-devel@alsa-project.org, linux-sound@vger.kernel.org, linux1394-devel@lists.sourceforge.net Subject: [PATCH 1/2][next] firewire: Avoid -Wflex-array-member-not-at-end warning Message-ID: References: Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally. There is currently a local structure `u` that is using a flexible `struct fw_iso_packet` as header for an on-stack array `u8 header[256]`. struct { struct fw_iso_packet packet; u8 header[256]; } u; However, we are deprecating flexible arrays in the middle of another struct. So, in order to avoid this, we use the `struct_group_tagged()` helper to separate the flexible array from the rest of the members in the flexible structure: struct fw_iso_packet { struct_group_tagged(fw_iso_packet_hdr, hdr, ... the rest of the members ); u32 header[]; /* tx: Top of 1394 isoch. data_block */ }; With the change described above, we can now declare an object of the type of the tagged struct, without embedding the flexible array in the middle of another struct: struct { struct fw_iso_packet_hdr packet; u8 header[256]; } u; We also use `container_of()` whenever we need to retrieve a pointer to the flexible structure, through which the flexible-array member can be accessed, as in this case. So, with these changes, fix the following warning: drivers/firewire/core-cdev.c: In function ‘ioctl_queue_iso’: drivers/firewire/core-cdev.c:1129:38: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] 1129 | struct fw_iso_packet packet; | ^~~~~~ Signed-off-by: Gustavo A. R. Silva --- drivers/firewire/core-cdev.c | 9 +++++---- include/linux/firewire.h | 16 +++++++++------- 2 files changed, 14 insertions(+), 11 deletions(-) diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c index 6274b86eb943..e1f1daa2e667 100644 --- a/drivers/firewire/core-cdev.c +++ b/drivers/firewire/core-cdev.c @@ -1126,9 +1126,11 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg) u32 control; int count; struct { - struct fw_iso_packet packet; + struct fw_iso_packet_hdr packet; u8 header[256]; } u; + struct fw_iso_packet *packet = + container_of(&u.packet, struct fw_iso_packet, hdr); if (ctx == NULL || a->handle != 0) return -EINVAL; @@ -1192,7 +1194,7 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg) if (next > end) return -EINVAL; if (copy_from_user - (u.packet.header, p->header, transmit_header_bytes)) + (packet->header, p->header, transmit_header_bytes)) return -EFAULT; if (u.packet.skip && ctx->type == FW_ISO_CONTEXT_TRANSMIT && u.packet.header_length + u.packet.payload_length > 0) @@ -1200,8 +1202,7 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg) if (payload + u.packet.payload_length > buffer_end) return -EINVAL; - if (fw_iso_context_queue(ctx, &u.packet, - &client->buffer, payload)) + if (fw_iso_context_queue(ctx, packet, &client->buffer, payload)) break; p = next; diff --git a/include/linux/firewire.h b/include/linux/firewire.h index dd9f2d765e68..becd3a60d0fb 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -456,13 +456,15 @@ void fw_core_remove_descriptor(struct fw_descriptor *desc); * scatter-gather streaming (e.g. assembling video frame automatically). */ struct fw_iso_packet { - u16 payload_length; /* Length of indirect payload */ - u32 interrupt:1; /* Generate interrupt on this packet */ - u32 skip:1; /* tx: Set to not send packet at all */ - /* rx: Sync bit, wait for matching sy */ - u32 tag:2; /* tx: Tag in packet header */ - u32 sy:4; /* tx: Sy in packet header */ - u32 header_length:8; /* Length of immediate header */ + struct_group_tagged(fw_iso_packet_hdr, hdr, + u16 payload_length; /* Length of indirect payload */ + u32 interrupt:1; /* Generate interrupt on this packet */ + u32 skip:1; /* tx: Set to not send packet at all */ + /* rx: Sync bit, wait for matching sy */ + u32 tag:2; /* tx: Tag in packet header */ + u32 sy:4; /* tx: Sy in packet header */ + u32 header_length:8; /* Length of immediate header */ + ); u32 header[]; /* tx: Top of 1394 isoch. data_block */ };