From patchwork Wed Feb 21 21:24:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 13566428 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 3628B12D76A; Wed, 21 Feb 2024 21:25:07 +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=fYBu4JDuTHzs7IVZa9hmYI/sybpJSLPG1hgkWgsUB1dw/XqqR4YiNDlIyhdrpG7Ndz61wEY/Y0AIdl+ZaOvoefkGOt2CZqtzRVqgCYxYwGKeYHDwDBjSS6k2dtJJKcGP4Q4b+R6pLZD/KVfQVqjbLkQLZ9oQ9a3lG/eNQnQS41w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708550707; c=relaxed/simple; bh=+wh5MLx6qw22a4Y5hCQZNo83AwcQ+EWK6GdCRZ0V+nQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=KRIZAaYoNEo2S9kCPhZWLMj0yXE75go2vwP28dMuNv+ElH4/9QI5x34+I7AqRDSHrJykGpLhDCJvslEOja4Kwtq8OGfCyVGSwS3fY3UuU13w72ArLrvPTMi6KlNaisGmaKYiyTJBhFzXC77EbFOMJJkFn+uUCDLyNoYonszVDp4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AK2yECFZ; 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="AK2yECFZ" Received: by smtp.kernel.org (Postfix) with ESMTPS id 0B327C341C0; Wed, 21 Feb 2024 21:25:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708550707; bh=+wh5MLx6qw22a4Y5hCQZNo83AwcQ+EWK6GdCRZ0V+nQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=AK2yECFZ23ei6Bxl7F8aU4RQFm0YNyCmD5DcPDYqym9xF7gaxYzUJ2X5OzxtyZ0Hw jPUD9OW85WtWmTmE6K2tld1wGbO2HH6O5MD688xPMXAjBVi4ya8mKxsVHOo779FDGV lRw2fvbhrPwugd44qEaOW8vEtMXx58eIHpkKUSZOaTRPoc58KcCScAZVwfupFGcWlX nkizFJHHKDqDwA4QMrPvtj0C1d55a4KCB/ohfrVyv7j5lzaDxLUoDXeFAtXCNDtgeN Nq7ynBMpMFENnCjJi7IdAuahdWZMWMT2NqQLBvoemxpz+mdl2HFCa007AGoS6/7zSY ziChLdNXv1sOQ== 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 ECE24C54791; Wed, 21 Feb 2024 21:25:06 +0000 (UTC) From: "Seth Forshee (DigitalOcean)" Date: Wed, 21 Feb 2024 15:24:49 -0600 Subject: [PATCH v2 18/25] fs: add vfs_set_fscaps() Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240221-idmap-fscap-refactor-v2-18-3039364623bd@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=3582; i=sforshee@kernel.org; h=from:subject:message-id; bh=+wh5MLx6qw22a4Y5hCQZNo83AwcQ+EWK6GdCRZ0V+nQ=; =?utf-8?q?b=3DowEBbQGS/pANAwAKAVMDma7l9DHJAcsmYgBl1mooRK6GQBMSPSNeq9TIC5Eyp?= =?utf-8?q?s87cR1e+jRyO5IO_L9tbqdiJATMEAAEKAB0WIQSQnt+rKAvnETy4Hc9TA5mu5fQxy?= =?utf-8?q?QUCZdZqKAAKCRBTA5mu5fQxybD1B/_9c/EK+CWeOAxlDfTdwJDnyY4A/3nNMB6EGt?= =?utf-8?q?r5LZ4F2yneQa64m4QIo+ZrLzxwRuKvGPtIkZCsgv3Wb_6VqtJ33/oxBPXedXR/8tZ?= =?utf-8?q?F8LC3tHmVHZfMcJiWkgNH1vM/2hjC3leSEQ3Srb60sYUy2gPEfXPlhWpe_h/pci4h?= =?utf-8?q?nVsUsdxdKrZxVZVwxFBuorxCAFi/1o0mLPD9pAPePer6DS5+YEVd3E+OgW7bBhAyD?= =?utf-8?q?biQacI_Rs7+v+o8JqU+YEueRgm1Wmn00s+iF4/Rr+LY78hTjMrqWSXqxGiaZhctJh?= =?utf-8?q?fft1eTDgbM1jEEsoYH6B?= N1daNdaH5CVnSWpjKxBb1/q+bBht8s 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 Provide a type-safe interface for setting filesystem capabilities and a generic implementation suitable for most filesystems. Signed-off-by: Seth Forshee (DigitalOcean) --- fs/xattr.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 2 files changed, 81 insertions(+) diff --git a/fs/xattr.c b/fs/xattr.c index 10d1b1f78fc2..96de43928a51 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -245,6 +245,85 @@ int vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, } EXPORT_SYMBOL(vfs_get_fscaps); +static int generic_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, + const struct vfs_caps *caps, int setxattr_flags) +{ + struct inode *inode = d_inode(dentry); + struct vfs_ns_cap_data nscaps; + int size; + + size = vfs_caps_to_xattr(idmap, i_user_ns(inode), caps, + &nscaps, sizeof(nscaps)); + if (size < 0) + return size; + + return __vfs_setxattr_noperm(idmap, dentry, XATTR_NAME_CAPS, + &nscaps, size, setxattr_flags); +} + +/** + * vfs_set_fscaps - set filesystem capabilities + * @idmap: idmap of the mount the inode was found from + * @dentry: the dentry on which to set filesystem capabilities + * @caps: the filesystem capabilities to be written + * @setxattr_flags: setxattr flags to use when writing the capabilities xattr + * + * This function writes the supplied filesystem capabilities to the dentry. + * + * Return: 0 on success, a negative errno on error. + */ +int vfs_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, + const struct vfs_caps *caps, int setxattr_flags) +{ + struct inode *inode = d_inode(dentry); + struct inode *delegated_inode = NULL; + int error; + +retry_deleg: + inode_lock(inode); + + error = xattr_permission(idmap, inode, XATTR_NAME_CAPS, MAY_WRITE); + if (error) + goto out_inode_unlock; + error = security_inode_set_fscaps(idmap, dentry, caps, setxattr_flags); + if (error) + goto out_inode_unlock; + + error = try_break_deleg(inode, &delegated_inode); + if (error) + goto out_inode_unlock; + + if (inode->i_opflags & IOP_XATTR) { + if (inode->i_op->set_fscaps) + error = inode->i_op->set_fscaps(idmap, dentry, caps, + setxattr_flags); + else + error = generic_set_fscaps(idmap, dentry, caps, + setxattr_flags); + if (!error) { + fsnotify_xattr(dentry); + security_inode_post_set_fscaps(idmap, dentry, caps, + setxattr_flags); + } + } else if (unlikely(is_bad_inode(inode))) { + error = -EIO; + } else { + error = -EOPNOTSUPP; + } + +out_inode_unlock: + inode_unlock(inode); + + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + + return error; +} +EXPORT_SYMBOL(vfs_set_fscaps); + int __vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, struct inode *inode, const char *name, const void *value, diff --git a/include/linux/fs.h b/include/linux/fs.h index d7cd2467e1ea..4f5d7ed44644 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2120,6 +2120,8 @@ extern int vfs_get_fscaps_nosec(struct mnt_idmap *idmap, struct dentry *dentry, struct vfs_caps *caps); extern int vfs_get_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, struct vfs_caps *caps); +extern int vfs_set_fscaps(struct mnt_idmap *idmap, struct dentry *dentry, + const struct vfs_caps *caps, int setxattr_flags); /** * enum freeze_holder - holder of the freeze