From patchwork Tue Oct 18 11:56:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 13010386 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B04D7C4167B for ; Tue, 18 Oct 2022 12:00:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230400AbiJRMAb (ORCPT ); Tue, 18 Oct 2022 08:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229800AbiJRL7f (ORCPT ); Tue, 18 Oct 2022 07:59:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 327B2BE2C7; Tue, 18 Oct 2022 04:58:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C22E16153B; Tue, 18 Oct 2022 11:58:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A997C43470; Tue, 18 Oct 2022 11:58:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666094304; bh=tqHKzPSoL5JMUl6N68cUoyGo4DHsJCIMSdlUIGLtj+w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qRmOReillSpWDrbLxV1jjCT53Gf5VI+oKaSX6DDumLpLrFoGrCw1dmsZXB261t2NA F3c5aSZ/2bEYQ5NYbs/YqhdafYHrBHUyMA6SXd5M+8F1ALrC5Pfi0aYcpjawubzsPO O3BW3hZZZoPzlbgIjoOsY/qekMSxtKTLdfQzaxMJEOcqFD3tJc4lFNsOy5n5TRWkBy JpIN2twn1C899EsgQFgTjzGPiwfEM390L3r3+RLRVK9NbVL4iS8gqkaud7c1YIhdwF NTMLbtHB7Df9Sw5mHdbSJ2bIr4+DrpQB/uS+gcy+rcpPKyY1kwIWhE6I21iXNUT+0Y jZCShftqMoJhQ== From: Christian Brauner To: linux-fsdevel@vger.kernel.org Cc: Christian Brauner , Seth Forshee , Christoph Hellwig , Al Viro , Mimi Zohar , linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, Paul Moore Subject: [PATCH v5 25/30] evm: remove evm_xattr_acl_change() Date: Tue, 18 Oct 2022 13:56:55 +0200 Message-Id: <20221018115700.166010-26-brauner@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221018115700.166010-1-brauner@kernel.org> References: <20221018115700.166010-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3926; i=brauner@kernel.org; h=from:subject; bh=tqHKzPSoL5JMUl6N68cUoyGo4DHsJCIMSdlUIGLtj+w=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMST7TdFsEJxabXfi3MuKCc8dfn/VNVk5v/enhllSVcjBGs8t rTckOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZiaMjwT62WR/WfRZaNdeD6gF2HD0 +KKazNDA1X8paffSc/QMHVg+Gf7dys448nOqtdPRZYy/Cpemlk1a2TF4yj376eVNxu/D2EEwA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: The security and integrity infrastructure has dedicated hooks now so evm_xattr_acl_change() is dead code. Before this commit the callchain was: evm_protect_xattr() -> evm_xattr_change() -> evm_xattr_acl_change() where evm_protect_xattr() was hit from evm_inode_setxattr() and evm_inode_removexattr(). But now we have evm_inode_set_acl() and evm_inode_remove_acl() and have switched over the vfs to rely on the posix acl api so the code isn't hit anymore. Suggested-by: Paul Moore Signed-off-by: Christian Brauner (Microsoft) --- Notes: /* v2 */ unchanged /* v3 */ Paul Moore : - Remove evm_xattr_acl_change() completely. /* v4 */ unchanged /* v5 */ unchanged security/integrity/evm/evm_main.c | 64 ------------------------------- 1 file changed, 64 deletions(-) diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index dcc5e704ef70..e074c2b4d499 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -434,66 +434,6 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) return evm_verify_hmac(dentry, NULL, NULL, 0, NULL); } -/* - * evm_xattr_acl_change - check if passed ACL changes the inode mode - * @mnt_userns: user namespace of the idmapped mount - * @dentry: pointer to the affected dentry - * @xattr_name: requested xattr - * @xattr_value: requested xattr value - * @xattr_value_len: requested xattr value length - * - * Check if passed ACL changes the inode mode, which is protected by EVM. - * - * Returns 1 if passed ACL causes inode mode change, 0 otherwise. - */ -static int evm_xattr_acl_change(struct user_namespace *mnt_userns, - struct dentry *dentry, const char *xattr_name, - const void *xattr_value, size_t xattr_value_len) -{ -#ifdef CONFIG_FS_POSIX_ACL - umode_t mode; - struct posix_acl *acl = NULL, *acl_res; - struct inode *inode = d_backing_inode(dentry); - int rc; - - /* - * An earlier comment here mentioned that the idmappings for - * ACL_{GROUP,USER} don't matter since EVM is only interested in the - * mode stored as part of POSIX ACLs. Nonetheless, if it must translate - * from the uapi POSIX ACL representation to the VFS internal POSIX ACL - * representation it should do so correctly. There's no guarantee that - * we won't change POSIX ACLs in a way that ACL_{GROUP,USER} matters - * for the mode at some point and it's difficult to keep track of all - * the LSM and integrity modules and what they do to POSIX ACLs. - * - * Frankly, EVM shouldn't try to interpret the uapi struct for POSIX - * ACLs it received. It requires knowledge that only the VFS is - * guaranteed to have. - */ - acl = vfs_set_acl_prepare(mnt_userns, i_user_ns(inode), - xattr_value, xattr_value_len); - if (IS_ERR_OR_NULL(acl)) - return 1; - - acl_res = acl; - /* - * Passing mnt_userns is necessary to correctly determine the GID in - * an idmapped mount, as the GID is used to clear the setgid bit in - * the inode mode. - */ - rc = posix_acl_update_mode(mnt_userns, inode, &mode, &acl_res); - - posix_acl_release(acl); - - if (rc) - return 1; - - if (inode->i_mode != mode) - return 1; -#endif - return 0; -} - /* * evm_xattr_change - check if passed xattr value differs from current value * @mnt_userns: user namespace of the idmapped mount @@ -513,10 +453,6 @@ static int evm_xattr_change(struct user_namespace *mnt_userns, char *xattr_data = NULL; int rc = 0; - if (posix_xattr_acl(xattr_name)) - return evm_xattr_acl_change(mnt_userns, dentry, xattr_name, - xattr_value, xattr_value_len); - rc = vfs_getxattr_alloc(&init_user_ns, dentry, xattr_name, &xattr_data, 0, GFP_NOFS); if (rc < 0)