From: Andreas Gruenbacher <agruenba@redhat.com> To: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@fieldses.org>, linux-nfs@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>, Andreas Gruenbacher <agruenba@redhat.com>, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org, Trond Myklebust <trond.myklebust@primarydata.com>, linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Christoph Hellwig <hch@infradead.org>, Andreas Dilger <adilger.kernel@dilger.ca>, linux-fsdevel@vger.kernel.org, Jeff Layton <jlayton@poochiereds.net>, linux-ext4@vger.kernel.org, Anna Schumaker <anna.schumaker@netapp.com> Subject: [PATCH v26 04/21] vfs: Add permission flags for setting file attributes Date: Thu, 29 Sep 2016 01:29:23 +0200 [thread overview] Message-ID: <1475105380-22837-5-git-send-email-agruenba@redhat.com> (raw) In-Reply-To: <1475105380-22837-1-git-send-email-agruenba@redhat.com> Richacls support permissions that allow to take ownership of a file, change the file permissions, and set the file timestamps. Support that by introducing new permission mask flags and by checking for those mask flags in setattr_prepare(). Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: J. Bruce Fields <bfields@redhat.com> Reviewed-by: Steve French <steve.french@primarydata.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> --- fs/attr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++--------- include/linux/fs.h | 3 +++ 2 files changed, 70 insertions(+), 12 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index c902b3d..8fa9869 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -17,6 +17,65 @@ #include <linux/ima.h> /** + * inode_extended_permission - permissions beyond read/write/execute + * + * Check for permissions that only richacls can currently grant. + */ +static int inode_extended_permission(struct inode *inode, int mask) +{ + if (!IS_RICHACL(inode)) + return -EPERM; + return inode_permission(inode, mask); +} + +static bool inode_uid_change_ok(struct inode *inode, kuid_t ia_uid) +{ + if (uid_eq(current_fsuid(), inode->i_uid) && + uid_eq(ia_uid, inode->i_uid)) + return true; + if (uid_eq(current_fsuid(), ia_uid) && + inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0) + return true; + if (capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return true; + return false; +} + +static bool inode_gid_change_ok(struct inode *inode, kgid_t ia_gid) +{ + int in_group = in_group_p(ia_gid); + if (uid_eq(current_fsuid(), inode->i_uid) && + (in_group || gid_eq(ia_gid, inode->i_gid))) + return true; + if (in_group && inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0) + return true; + if (capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return true; + return false; +} + +/** + * inode_owner_permitted_or_capable + * + * Check for permissions implicitly granted to the owner, like MAY_CHMOD or + * MAY_SET_TIMES. Equivalent to inode_owner_or_capable for file systems + * without support for those permissions. + */ +static bool inode_owner_permitted_or_capable(struct inode *inode, int mask) +{ + struct user_namespace *ns; + + if (uid_eq(current_fsuid(), inode->i_uid)) + return true; + if (inode_extended_permission(inode, mask) == 0) + return true; + ns = current_user_ns(); + if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) + return true; + return false; +} + +/** * setattr_prepare - check if attribute changes to a dentry are allowed * @dentry: dentry to check * @attr: attributes to change @@ -50,22 +109,18 @@ int setattr_prepare(struct dentry *dentry, struct iattr *attr) goto kill_priv; /* Make sure a caller can chown. */ - if ((ia_valid & ATTR_UID) && - (!uid_eq(current_fsuid(), inode->i_uid) || - !uid_eq(attr->ia_uid, inode->i_uid)) && - !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) - return -EPERM; + if (ia_valid & ATTR_UID) + if (!inode_uid_change_ok(inode, attr->ia_uid)) + return -EPERM; /* Make sure caller can chgrp. */ - if ((ia_valid & ATTR_GID) && - (!uid_eq(current_fsuid(), inode->i_uid) || - (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) && - !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) - return -EPERM; + if (ia_valid & ATTR_GID) + if (!inode_gid_change_ok(inode, attr->ia_gid)) + return -EPERM; /* Make sure a caller can chmod. */ if (ia_valid & ATTR_MODE) { - if (!inode_owner_or_capable(inode)) + if (!inode_owner_permitted_or_capable(inode, MAY_CHMOD)) return -EPERM; /* Also check the setgid bit! */ if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : @@ -76,7 +131,7 @@ int setattr_prepare(struct dentry *dentry, struct iattr *attr) /* Check for setting the inode time. */ if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { - if (!inode_owner_or_capable(inode)) + if (!inode_owner_permitted_or_capable(inode, MAY_SET_TIMES)) return -EPERM; } diff --git a/include/linux/fs.h b/include/linux/fs.h index f3e21b0..3ab7372 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -88,6 +88,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_CREATE_DIR 0x00000200 #define MAY_DELETE_CHILD 0x00000400 #define MAY_DELETE_SELF 0x00000800 +#define MAY_TAKE_OWNERSHIP 0x00001000 +#define MAY_CHMOD 0x00002000 +#define MAY_SET_TIMES 0x00004000 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.7.4 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs
WARNING: multiple messages have this Message-ID (diff)
From: Andreas Gruenbacher <agruenba@redhat.com> To: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Gruenbacher <agruenba@redhat.com>, Christoph Hellwig <hch@infradead.org>, "Theodore Ts'o" <tytso@mit.edu>, Andreas Dilger <adilger.kernel@dilger.ca>, "J. Bruce Fields" <bfields@fieldses.org>, Jeff Layton <jlayton@poochiereds.net>, Trond Myklebust <trond.myklebust@primarydata.com>, Anna Schumaker <anna.schumaker@netapp.com>, Dave Chinner <david@fromorbit.com>, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-api@vger.kernel.org Subject: [PATCH v26 04/21] vfs: Add permission flags for setting file attributes Date: Thu, 29 Sep 2016 01:29:23 +0200 [thread overview] Message-ID: <1475105380-22837-5-git-send-email-agruenba@redhat.com> (raw) In-Reply-To: <1475105380-22837-1-git-send-email-agruenba@redhat.com> Richacls support permissions that allow to take ownership of a file, change the file permissions, and set the file timestamps. Support that by introducing new permission mask flags and by checking for those mask flags in setattr_prepare(). Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: J. Bruce Fields <bfields@redhat.com> Reviewed-by: Steve French <steve.french@primarydata.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> --- fs/attr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++--------- include/linux/fs.h | 3 +++ 2 files changed, 70 insertions(+), 12 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index c902b3d..8fa9869 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -17,6 +17,65 @@ #include <linux/ima.h> /** + * inode_extended_permission - permissions beyond read/write/execute + * + * Check for permissions that only richacls can currently grant. + */ +static int inode_extended_permission(struct inode *inode, int mask) +{ + if (!IS_RICHACL(inode)) + return -EPERM; + return inode_permission(inode, mask); +} + +static bool inode_uid_change_ok(struct inode *inode, kuid_t ia_uid) +{ + if (uid_eq(current_fsuid(), inode->i_uid) && + uid_eq(ia_uid, inode->i_uid)) + return true; + if (uid_eq(current_fsuid(), ia_uid) && + inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0) + return true; + if (capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return true; + return false; +} + +static bool inode_gid_change_ok(struct inode *inode, kgid_t ia_gid) +{ + int in_group = in_group_p(ia_gid); + if (uid_eq(current_fsuid(), inode->i_uid) && + (in_group || gid_eq(ia_gid, inode->i_gid))) + return true; + if (in_group && inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0) + return true; + if (capable_wrt_inode_uidgid(inode, CAP_CHOWN)) + return true; + return false; +} + +/** + * inode_owner_permitted_or_capable + * + * Check for permissions implicitly granted to the owner, like MAY_CHMOD or + * MAY_SET_TIMES. Equivalent to inode_owner_or_capable for file systems + * without support for those permissions. + */ +static bool inode_owner_permitted_or_capable(struct inode *inode, int mask) +{ + struct user_namespace *ns; + + if (uid_eq(current_fsuid(), inode->i_uid)) + return true; + if (inode_extended_permission(inode, mask) == 0) + return true; + ns = current_user_ns(); + if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) + return true; + return false; +} + +/** * setattr_prepare - check if attribute changes to a dentry are allowed * @dentry: dentry to check * @attr: attributes to change @@ -50,22 +109,18 @@ int setattr_prepare(struct dentry *dentry, struct iattr *attr) goto kill_priv; /* Make sure a caller can chown. */ - if ((ia_valid & ATTR_UID) && - (!uid_eq(current_fsuid(), inode->i_uid) || - !uid_eq(attr->ia_uid, inode->i_uid)) && - !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) - return -EPERM; + if (ia_valid & ATTR_UID) + if (!inode_uid_change_ok(inode, attr->ia_uid)) + return -EPERM; /* Make sure caller can chgrp. */ - if ((ia_valid & ATTR_GID) && - (!uid_eq(current_fsuid(), inode->i_uid) || - (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) && - !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) - return -EPERM; + if (ia_valid & ATTR_GID) + if (!inode_gid_change_ok(inode, attr->ia_gid)) + return -EPERM; /* Make sure a caller can chmod. */ if (ia_valid & ATTR_MODE) { - if (!inode_owner_or_capable(inode)) + if (!inode_owner_permitted_or_capable(inode, MAY_CHMOD)) return -EPERM; /* Also check the setgid bit! */ if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : @@ -76,7 +131,7 @@ int setattr_prepare(struct dentry *dentry, struct iattr *attr) /* Check for setting the inode time. */ if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { - if (!inode_owner_or_capable(inode)) + if (!inode_owner_permitted_or_capable(inode, MAY_SET_TIMES)) return -EPERM; } diff --git a/include/linux/fs.h b/include/linux/fs.h index f3e21b0..3ab7372 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -88,6 +88,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_CREATE_DIR 0x00000200 #define MAY_DELETE_CHILD 0x00000400 #define MAY_DELETE_SELF 0x00000800 +#define MAY_TAKE_OWNERSHIP 0x00001000 +#define MAY_CHMOD 0x00002000 +#define MAY_SET_TIMES 0x00004000 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 2.7.4
next prev parent reply other threads:[~2016-09-28 23:29 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-09-28 23:29 [PATCH v25 00/21] Richacls (Core and Ext4) Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 01/21] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 02/21] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 03/21] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher [this message] 2016-09-28 23:29 ` [PATCH v26 04/21] vfs: Add permission flags for setting file attributes Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 05/21] richacl: In-memory representation and helper functions Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 06/21] richacl: Permission mapping functions Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 07/21] richacl: Permission check algorithm Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 08/21] richacl: Compute maximum file masks from an acl Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 10/21] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher [not found] ` <1475105380-22837-1-git-send-email-agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 2016-09-28 23:29 ` [PATCH v26 09/21] vfs: Cache base_acl objects in inodes Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 11/21] vfs: Cache richacl in struct inode Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-30 16:11 ` [PATCH v25 00/21] Richacls (Core and Ext4) J. Bruce Fields 2016-09-30 16:11 ` J. Bruce Fields 2016-09-30 16:11 ` J. Bruce Fields 2016-09-28 23:29 ` [PATCH v26 12/21] richacl: Update the file masks in chmod() Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 13/21] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 14/21] richacl: Create-time inheritance Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 15/21] richacl: Automatic Inheritance Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 16/21] richacl: xattr mapping functions Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 17/21] richacl: Add richacl xattr handler Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 18/21] vfs: Add richacl permission checking Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 19/21] vfs: Move check_posix_acl and check_richacl out of fs/namei.c Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 20/21] ext4: Add richacl support Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher 2016-09-28 23:29 ` [PATCH v26 21/21] ext4: Add richacl feature flag Andreas Gruenbacher 2016-09-28 23:29 ` Andreas Gruenbacher
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