From patchwork Wed Jul 24 02:06:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xu Kuohai X-Patchwork-Id: 13740547 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 4D14A1171C; Wed, 24 Jul 2024 01:57:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721786224; cv=none; b=GMrPaToXtqaTbumDupcCAmxMyJkEkU9P7PWmX+fTJ1u2dGBlhVinWinGHyIsTpkmENc8h1uQd6VNDncqTpASMISXl5Q1t/VIaytXCdRzgd+p7mjek9Gh+hjKIAvBbxyT8BdZkLAh6DlUAETvZxeRnK7VtSl16ddevQTFvGrmrh0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721786224; c=relaxed/simple; bh=WJWRcqsesXwYwAt1BcpzmR0xuMOTS3AEdFL6VnirlvM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=c+yISQdOC4QbwYp1OLAy3Oxbr9kXQY33kDKK/721+miPjtKw5YtZkQxgyPmD1VYEmi3jPcXPBjVlTHde3yfj13vJ59wzdq2Vo9WGdKfY3d1GYyqCU8LRuDp6U9FW6ZNXfIWryDk2dmiNDoNpxRmpJ09l6NdSi1Y8WPI99DG3AdQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4WTHF24TVdz4f3kw5; Wed, 24 Jul 2024 09:56:38 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id 2EF6D1A190F; Wed, 24 Jul 2024 09:56:52 +0800 (CST) Received: from k01.huawei.com (unknown [10.67.174.197]) by APP1 (Coremail) with SMTP id cCh0CgDXw3VgX6BmaKTZAw--.12072S4; Wed, 24 Jul 2024 09:56:51 +0800 (CST) From: Xu Kuohai To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-integrity@vger.kernel.org Cc: Paul Moore , Casey Schaufler , "Serge E . Hallyn" , Miklos Szeredi , Amir Goldstein , James Morris , Mimi Zohar , Roberto Sassu , Dmitry Kasatkin , Eric Snowberg , Stephen Smalley , Ondrej Mosnacek Subject: [PATCH v1 2/2] lsm: Refactor return value of LSM hook inode_copy_up_xattr Date: Wed, 24 Jul 2024 10:06:59 +0800 Message-Id: <20240724020659.120353-3-xukuohai@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240724020659.120353-1-xukuohai@huaweicloud.com> References: <20240724020659.120353-1-xukuohai@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cCh0CgDXw3VgX6BmaKTZAw--.12072S4 X-Coremail-Antispam: 1UD129KBjvJXoWxAw1kXF4DJFWkXFWrJF1fJFb_yoWrZF1fpa 1Dtan2qr1rJFy7XFykJa17ua1F93yrGFWUC39xuw12kFZ3Xrs3Wryayr12kr45Wry8JF4v qanFvrs8C3W5t3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPFb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI 0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG 67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MI IYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E 14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJV W8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUFSdy UUUUU X-CM-SenderInfo: 50xn30hkdlqx5xdzvxpfor3voofrz/ From: Xu Kuohai To be consistent with most LSM hooks, convert the return value of hook inode_copy_up_xattr to 0 or a negative error code. Before: - Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. After: - Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED* when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. Signed-off-by: Xu Kuohai --- fs/overlayfs/copy_up.c | 6 +++--- security/integrity/evm/evm_main.c | 2 +- security/security.c | 11 +++-------- security/selinux/hooks.c | 4 ++-- security/smack/smack_lsm.c | 6 +++--- 5 files changed, 12 insertions(+), 17 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index a5ef2005a2cc..337a5be99ac9 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -115,12 +115,12 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de continue; error = security_inode_copy_up_xattr(old, name); - if (error < 0 && error != -EOPNOTSUPP) - break; - if (error == 1) { + if (error == -ECANCELED) { error = 0; continue; /* Discard */ } + if (error < 0 && error != -EOPNOTSUPP) + break; if (is_posix_acl_xattr(name)) { error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name); diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 62fe66dd53ce..6924ed508ebd 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -1000,7 +1000,7 @@ static int evm_inode_copy_up_xattr(struct dentry *src, const char *name) case EVM_XATTR_HMAC: case EVM_IMA_XATTR_DIGSIG: default: - rc = 1; /* discard */ + rc = -ECANCELED; /* discard */ } kfree(xattr_data); diff --git a/security/security.c b/security/security.c index ff5cca992ee1..ca93d43ad475 100644 --- a/security/security.c +++ b/security/security.c @@ -2760,19 +2760,14 @@ EXPORT_SYMBOL(security_inode_copy_up); * lower layer to the union/overlay layer. The caller is responsible for * reading and writing the xattrs, this hook is merely a filter. * - * Return: Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP - * if the security module does not know about attribute, or a negative - * error code to abort the copy up. + * Return: Returns 0 to accept the xattr, -ECANCELED to discard the xattr, + * -EOPNOTSUPP if the security module does not know about attribute, + * or a negative error code to abort the copy up. */ int security_inode_copy_up_xattr(struct dentry *src, const char *name) { int rc; - /* - * The implementation can return 0 (accept the xattr), 1 (discard the - * xattr), -EOPNOTSUPP if it does not know anything about the xattr or - * any other error code in case of an error. - */ rc = call_int_hook(inode_copy_up_xattr, src, name); if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr)) return rc; diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index af7467cdd181..81fbfa5b80d4 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3531,8 +3531,8 @@ static int selinux_inode_copy_up_xattr(struct dentry *dentry, const char *name) * xattrs up. Instead, filter out SELinux-related xattrs following * policy load. */ - if (selinux_initialized() && strcmp(name, XATTR_NAME_SELINUX) == 0) - return 1; /* Discard */ + if (selinux_initialized() && !strcmp(name, XATTR_NAME_SELINUX)) + return -ECANCELED; /* Discard */ /* * Any other attribute apart from SELINUX is not claimed, supported * by selinux. diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index b0e0205a5724..09ff7f24c0c6 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4902,10 +4902,10 @@ static int smack_inode_copy_up(struct dentry *dentry, struct cred **new) static int smack_inode_copy_up_xattr(struct dentry *src, const char *name) { /* - * Return 1 if this is the smack access Smack attribute. + * Return -ECANCELED if this is the smack access Smack attribute. */ - if (strcmp(name, XATTR_NAME_SMACK) == 0) - return 1; + if (!strcmp(name, XATTR_NAME_SMACK)) + return -ECANCELED; return -EOPNOTSUPP; }