From patchwork Wed Feb 21 21:24:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Seth Forshee (DigitalOcean)" X-Patchwork-Id: 13566391 X-Patchwork-Delegate: paul@paul-moore.com 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 D598712AAE2; Wed, 21 Feb 2024 21:25:06 +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=1708550707; cv=none; b=bxM94GCzQ6Qi8Oqgyl3TXv3uJYZ9iMhg/RGGlvSPa+TAp14XczAA2Ous2lD0nBlkzGMnR497dyekF3NdkT/FhSNMTs6NzHzN9r8izkAS/bWt3W0IPYYHdjlUCecZV/BorsvcGPMMLAXfAPTxnRi9GDSowapVC60YNn9Y/qDM0V4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708550707; c=relaxed/simple; bh=Yr3ph0XCYOXrp9CXWdQMd7IWQbhJjbtCnaMZrcY53gY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=bw/i2eZcirMgisYTFexaGG9ezqUkiUYSYFEU+WtPovHo4VU8V3IqA05fTFXLS+DN4TvL2cEnJLSvjX0TOWdEzpSuz5fHhCvBZaJx7MfK8b9lM00FIad3Jy99EUTXQrsRps9bBdoc4YQaaye80Lw9V9zYqnj0ga/oJN3aFUq5ljw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lzqK00wH; 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="lzqK00wH" Received: by smtp.kernel.org (Postfix) with ESMTPS id B5D8FC32790; Wed, 21 Feb 2024 21:25:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708550706; bh=Yr3ph0XCYOXrp9CXWdQMd7IWQbhJjbtCnaMZrcY53gY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=lzqK00wHaspxkj8s4YixHYBHO5uRXAEZjNOy9Tt0Z+zVFhBNoRvYu/G86zief0nKx DOC8vrh8C8IjEHbdu7wwreh1NNB3LwwbqMH0XaZWH+IykU6H5BTj1w/GUbwEY07O5Z pvwC+B2b6olS/XcTYKLHEbL6kmg/L1ovWhiGt+wN7z3/EUgIDJm5CNvALRd0UvLCPr YN7WDcK0FDtDVAfriM9B0F3WsZlZvlWdTcQPII7bNMfNd41fGQdq/VjOUrAZzeTnvH ZJaeZRN5maBuF9hI2NOJ5ijYh2cBqpS/xIahdqiP82EiiWzznvttVF2LXIWeD/RRi7 EhxIDDDI3G5bw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E1A0C54791; Wed, 21 Feb 2024 21:25:06 +0000 (UTC) From: "Seth Forshee (DigitalOcean)" Date: Wed, 21 Feb 2024 15:24:45 -0600 Subject: [PATCH v2 14/25] evm: add support for fscaps security hooks Precedence: bulk X-Mailing-List: audit@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240221-idmap-fscap-refactor-v2-14-3039364623bd@kernel.org> References: <20240221-idmap-fscap-refactor-v2-0-3039364623bd@kernel.org> In-Reply-To: <20240221-idmap-fscap-refactor-v2-0-3039364623bd@kernel.org> To: Christian Brauner , Seth Forshee , Serge Hallyn , Paul Moore , Eric Paris , James Morris , Alexander Viro , Jan Kara , Stephen Smalley , Ondrej Mosnacek , Casey Schaufler , Mimi Zohar , Roberto Sassu , Dmitry Kasatkin , Eric Snowberg , "Matthew Wilcox (Oracle)" , Jonathan Corbet , Miklos Szeredi , Amir Goldstein Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, audit@vger.kernel.org, selinux@vger.kernel.org, linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org, linux-unionfs@vger.kernel.org X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=openpgp-sha256; l=4327; i=sforshee@kernel.org; h=from:subject:message-id; bh=Yr3ph0XCYOXrp9CXWdQMd7IWQbhJjbtCnaMZrcY53gY=; =?utf-8?q?b=3DowEBbQGS/pANAwAKAVMDma7l9DHJAcsmYgBl1mol25TRgD1iHEn0O+Lzt/PUv?= =?utf-8?q?oaNtWltRiGhhXzf_m3QV75SJATMEAAEKAB0WIQSQnt+rKAvnETy4Hc9TA5mu5fQxy?= =?utf-8?q?QUCZdZqJQAKCRBTA5mu5fQxyS9CB/_9kSIwlWp/cTH5n9oXEiY7IRY7QctvMWegFy?= =?utf-8?q?imx7di5G0HHXG0GkFzYw+GCyZNDCVL5R5AuZIagZMKH_cytRQKwJZdn+UxoBt7VxR?= =?utf-8?q?cVA0NXxcM5vRXXYDzuNpVQNmbfH5HvHaFvaIDzOEYFmJqsIW/jaxzfWVB_RjglGLz?= =?utf-8?q?pDryq2M/ZCsQx9KBTGmEwTBnxzalQNyrtvXgG4UHhg2ZBqBAWhD3SNXDCf7Ii95JG?= =?utf-8?q?mya1vE_xyBqVMzbjM3/l+t7NBgQWvLHaHz7A3od4uGdwyYRfroyU95TFJcCTgcv4b?= =?utf-8?q?gK682Ja2e9Zo3X4dw5Wp?= Ka5r0Q2dpUgYDHMm+pijpjRjRaNrcP X-Developer-Key: i=sforshee@kernel.org; a=openpgp; fpr=2ABCA7498D83E1D32D51D3B5AB4800A62DB9F73A X-Endpoint-Received: by B4 Relay for sforshee@kernel.org/default with auth_id=103 Support the new fscaps security hooks by converting the vfs_caps to raw xattr data and then handling them the same as other xattrs. Signed-off-by: Seth Forshee (DigitalOcean) --- include/linux/evm.h | 39 +++++++++++++++++++++++++ security/integrity/evm/evm_main.c | 60 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 99 insertions(+) diff --git a/include/linux/evm.h b/include/linux/evm.h index 36ec884320d9..aeb9ff52ad22 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -57,6 +57,20 @@ static inline void evm_inode_post_set_acl(struct dentry *dentry, { return evm_inode_post_setxattr(dentry, acl_name, NULL, 0); } +extern int evm_inode_set_fscaps(struct mnt_idmap *idmap, + struct dentry *dentry, + const struct vfs_caps *caps, int flags); +static inline int evm_inode_remove_fscaps(struct dentry *dentry) +{ + return evm_inode_set_fscaps(&nop_mnt_idmap, dentry, NULL, XATTR_REPLACE); +} +extern void evm_inode_post_set_fscaps(struct mnt_idmap *idmap, + struct dentry *dentry, + const struct vfs_caps *caps, int flags); +static inline void evm_inode_post_remove_fscaps(struct dentry *dentry) +{ + return evm_inode_post_set_fscaps(&nop_mnt_idmap, dentry, NULL, 0); +} int evm_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, @@ -164,6 +178,31 @@ static inline void evm_inode_post_set_acl(struct dentry *dentry, return; } +static inline int evm_inode_set_fscaps(struct mnt_idmap *idmap, + struct dentry *dentry, + const struct vfs_caps *caps, int flags) +{ + return 0; +} + +static inline int evm_inode_remove_fscaps(struct dentry *dentry) +{ + return 0; +} + +static inline void evm_inode_post_set_fscaps(struct mnt_idmap *idmap, + struct dentry *dentry, + const struct vfs_caps *caps, + int flags) +{ + return; +} + +static inline void evm_inode_post_remove_fscaps(struct dentry *dentry) +{ + return; +} + static inline int evm_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index cc7956d7878b..ecf4634a921a 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -805,6 +805,66 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) evm_update_evmxattr(dentry, xattr_name, NULL, 0); } +int evm_inode_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, + const struct vfs_caps *caps, int flags) +{ + struct inode *inode = d_inode(dentry); + struct vfs_ns_cap_data nscaps; + const void *xattr_data = NULL; + int size = 0; + + /* Policy permits modification of the protected xattrs even though + * there's no HMAC key loaded + */ + if (evm_initialized & EVM_ALLOW_METADATA_WRITES) + return 0; + + if (caps) { + size = vfs_caps_to_xattr(idmap, i_user_ns(inode), caps, &nscaps, + sizeof(nscaps)); + if (size < 0) + return size; + xattr_data = &nscaps; + } + + return evm_protect_xattr(idmap, dentry, XATTR_NAME_CAPS, xattr_data, size); +} + +void evm_inode_post_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, + const struct vfs_caps *caps, int flags) +{ + struct inode *inode = d_inode(dentry); + struct vfs_ns_cap_data nscaps; + const void *xattr_data = NULL; + int size = 0; + + if (!evm_revalidate_status(XATTR_NAME_CAPS)) + return; + + evm_reset_status(dentry->d_inode); + + if (!(evm_initialized & EVM_INIT_HMAC)) + return; + + if (is_unsupported_fs(dentry)) + return; + + if (caps) { + size = vfs_caps_to_xattr(idmap, i_user_ns(inode), caps, &nscaps, + sizeof(nscaps)); + /* + * The fscaps here should have been converted to an xattr by + * evm_inode_set_fscaps() already, so a failure to convert + * here is a bug. + */ + if (WARN_ON_ONCE(size < 0)) + return; + xattr_data = &nscaps; + } + + evm_update_evmxattr(dentry, XATTR_NAME_CAPS, xattr_data, size); +} + static int evm_attr_change(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr) {