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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0386EB64DC for ; Fri, 14 Jul 2023 20:54:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689368064; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=HVTO/9J62dnF8jOO1csBEN4qjpqAxKHltYr5ZylFd7w=; b=DxtATbVo03l+8ZioIhDacKRivAhTiRCh5a8b87sCdero8BngozAP4hpRwUobJGhN0uPyUz 3uLqg6LR+XRKkAOsEseMpqgQ7h66It31Fs6Uf5cI3lImeZROWHwoMdrmN++F/JiDFOiIn1 BfU0q+39i8Mkm/1umoDqHE/XFsf1czg= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-277-5F9A8kSdNYiURGvmI-6ynA-1; Fri, 14 Jul 2023 16:54:19 -0400 X-MC-Unique: 5F9A8kSdNYiURGvmI-6ynA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 252241C05AA0; Fri, 14 Jul 2023 20:54:15 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12D9A4CD0E3; Fri, 14 Jul 2023 20:54:15 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 9CD521946A4B; Fri, 14 Jul 2023 20:54:12 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 6B8491946A4A for ; Fri, 14 Jul 2023 20:54:11 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 4F7344087C67; Fri, 14 Jul 2023 20:54:11 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast09.extmail.prod.ext.rdu2.redhat.com [10.11.55.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 487D64087C62 for ; Fri, 14 Jul 2023 20:54:11 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2920929AA39A for ; Fri, 14 Jul 2023 20:54:11 +0000 (UTC) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-161-KNwm47F1OhKwNAPUVlqDFg-1; Fri, 14 Jul 2023 16:54:09 -0400 X-MC-Unique: KNwm47F1OhKwNAPUVlqDFg-1 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BA1DC61DF9; Fri, 14 Jul 2023 20:54:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F282C433C7; Fri, 14 Jul 2023 20:54:07 +0000 (UTC) From: Sasha Levin To: stable-commits@vger.kernel.org, demi@invisiblethingslab.com Date: Fri, 14 Jul 2023 16:54:05 -0400 Message-Id: <20230714205405.1301874-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Subject: [dm-devel] Patch "dm ioctl: Avoid double-fetch of version" has been added to the 6.1-stable tree X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com, Mike Snitzer , Alasdair Kergon Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit This is a note to let you know that I've just added the patch titled dm ioctl: Avoid double-fetch of version to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-ioctl-avoid-double-fetch-of-version.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. commit edad1af6376d882614441fb3632a88a31e49a527 Author: Demi Marie Obenour Date: Sat Jun 3 10:52:42 2023 -0400 dm ioctl: Avoid double-fetch of version [ Upstream commit 249bed821b4db6d95a99160f7d6d236ea5fe6362 ] The version is fetched once in check_version(), which then does some validation and then overwrites the version in userspace with the API version supported by the kernel. copy_params() then fetches the version from userspace *again*, and this time no validation is done. The result is that the kernel's version number is completely controllable by userspace, provided that userspace can win a race condition. Fix this flaw by not copying the version back to the kernel the second time. This is not exploitable as the version is not further used in the kernel. However, it could become a problem if future patches start relying on the version field. Cc: stable@vger.kernel.org Signed-off-by: Demi Marie Obenour Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 6aeae095086d7..2afd2d2a0f407 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1811,30 +1811,36 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) * As well as checking the version compatibility this always * copies the kernel interface version out. */ -static int check_version(unsigned int cmd, struct dm_ioctl __user *user) +static int check_version(unsigned int cmd, struct dm_ioctl __user *user, + struct dm_ioctl *kernel_params) { - uint32_t version[3]; int r = 0; - if (copy_from_user(version, user->version, sizeof(version))) + /* Make certain version is first member of dm_ioctl struct */ + BUILD_BUG_ON(offsetof(struct dm_ioctl, version) != 0); + + if (copy_from_user(kernel_params->version, user->version, sizeof(kernel_params->version))) return -EFAULT; - if ((version[0] != DM_VERSION_MAJOR) || - (version[1] > DM_VERSION_MINOR)) { + if ((kernel_params->version[0] != DM_VERSION_MAJOR) || + (kernel_params->version[1] > DM_VERSION_MINOR)) { DMERR("ioctl interface mismatch: kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)", DM_VERSION_MAJOR, DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, - version[0], version[1], version[2], cmd); + kernel_params->version[0], + kernel_params->version[1], + kernel_params->version[2], + cmd); r = -EINVAL; } /* * Fill in the kernel version. */ - version[0] = DM_VERSION_MAJOR; - version[1] = DM_VERSION_MINOR; - version[2] = DM_VERSION_PATCHLEVEL; - if (copy_to_user(user->version, version, sizeof(version))) + kernel_params->version[0] = DM_VERSION_MAJOR; + kernel_params->version[1] = DM_VERSION_MINOR; + kernel_params->version[2] = DM_VERSION_PATCHLEVEL; + if (copy_to_user(user->version, kernel_params->version, sizeof(kernel_params->version))) return -EFAULT; return r; @@ -1860,7 +1866,10 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern const size_t minimum_data_size = offsetof(struct dm_ioctl, data); unsigned int noio_flag; - if (copy_from_user(param_kernel, user, minimum_data_size)) + /* check_version() already copied version from userspace, avoid TOCTOU */ + if (copy_from_user((char *)param_kernel + sizeof(param_kernel->version), + (char __user *)user + sizeof(param_kernel->version), + minimum_data_size - sizeof(param_kernel->version))) return -EFAULT; if (param_kernel->data_size < minimum_data_size) { @@ -1972,7 +1981,7 @@ static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *us * Check the interface version passed in. This also * writes out the kernel's interface version. */ - r = check_version(cmd, user); + r = check_version(cmd, user, ¶m_kernel); if (r) return r; -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel