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 E35F925DB0D; Tue, 11 Mar 2025 15:12:18 +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=1741705939; cv=none; b=YQ2aoNM0NoRytyKTaAPziPzDBSN9TOTtLmbdLC7SQPBSsxkKtsmOLCn9N2X4ANW/bCx62yyevpP06ggAtg526b8MDe7FrJzebNKBZMsIyl9yjCJX2X/hG+Jv0AOINIMkq6nuFYUfzJZibPRk0nQOyCqTpUZ1RJX4H4ysBBYs4pk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741705939; c=relaxed/simple; bh=xqk5IuAoAWszbJhLgO/XM58I/a5TLmoWeuaqH7GSjVA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FPxg5Ra2INO9G2Kn5PsfLnxdHppa0ZN7qcQ2isD+rZRZffG/TvsJfFaJ1Cw4J+xDuct1RlvRc6znbKSVlUNCdmwZ9s7cENayIpdTvM1HztIiuh6sELWdvNQHutDR26pb2HGvgKbdjrk+8M61ixQgLZTGOsf6qn7HUTJAHISJpxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tNrjO9JS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tNrjO9JS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFA69C4CEEA; Tue, 11 Mar 2025 15:12:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741705938; bh=xqk5IuAoAWszbJhLgO/XM58I/a5TLmoWeuaqH7GSjVA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tNrjO9JSMq9bkSVI+/RpZI8wUxPnGdpr/EP1cNbhDojSq65Flqm/PDszaGlCHMHW3 vhlqu7gkmPBqEaM4GIarzD55ofyYfpUnK30tjHh+eExb3K6otL5RD0ZSuVtfAbzeU9 4Rxaftx1mziCeEIrS1yNK7GrnycR6Lj3Mz9TMuHY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Jann Horn Subject: [PATCH 5.4 188/328] usb: cdc-acm: Fix handling of oversized fragments Date: Tue, 11 Mar 2025 15:59:18 +0100 Message-ID: <20250311145722.369939901@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250311145714.865727435@linuxfoundation.org> References: <20250311145714.865727435@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit 12e712964f41d05ae034989892de445781c46730 upstream. If we receive an initial fragment of size 8 bytes which specifies a wLength of 1 byte (so the reassembled message is supposed to be 9 bytes long), and we then receive a second fragment of size 9 bytes (which is not supposed to happen), we currently wrongly bypass the fragment reassembly code but still pass the pointer to the acm->notification_buffer to acm_process_notification(). Make this less wrong by always going through fragment reassembly when we expect more fragments. Before this patch, receiving an overlong fragment could lead to `newctrl` in acm_process_notification() being uninitialized data (instead of data coming from the device). Cc: stable Fixes: ea2583529cd1 ("cdc-acm: reassemble fragmented notifications") Signed-off-by: Jann Horn Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -404,7 +404,7 @@ static void acm_ctrl_irq(struct urb *urb expected_size = sizeof(struct usb_cdc_notification) + le16_to_cpu(dr->wLength); - if (current_size < expected_size) { + if (acm->nb_index != 0 || current_size < expected_size) { /* notification is transmitted fragmented, reassemble */ if (acm->nb_size < expected_size) { u8 *new_buffer;