From: Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nfs@vger.kernel.org
Subject: [RFC v3 09/45] vfs: Add permission flags for setting file attributes
Date: Fri, 24 Apr 2015 13:04:06 +0200 [thread overview]
Message-ID: <a16a50a48cdaa2363b787f5516affd93874585c7.1429868795.git.agruenba@redhat.com> (raw)
In-Reply-To: <cover.1429868795.git.agruenba@redhat.com>
In-Reply-To: <cover.1429868795.git.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
inode_change_ok().
Signed-off-by: Andreas Gruenbacher <agruenba@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 328be71..85483e0 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;
+}
+
+/**
* inode_change_ok - check if attribute changes to an inode are allowed
* @inode: inode to check
* @attr: attributes to change
@@ -47,22 +106,18 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
return 0;
/* 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 :
@@ -73,7 +128,7 @@ int inode_change_ok(struct inode *inode, 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 8347f81..0121047 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -84,6 +84,9 @@ typedef void (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
--
2.1.0
next prev parent reply other threads:[~2015-04-24 11:04 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-24 11:03 [RFC v3 00/45] Richacls Andreas Gruenbacher
2015-04-24 11:03 ` [RFC v3 01/45] vfs: Minor documentation fix Andreas Gruenbacher
2015-04-24 11:03 ` [RFC v3 02/45] uapi: Remove kernel internal declaration Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 03/45] nfsd: Checking for acl support does not require fetching any acls Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 04/45] vfs: Shrink struct posix_acl Andreas Gruenbacher
2015-04-25 7:56 ` Rasmus Villemoes
2015-04-27 10:27 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 05/45] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 06/45] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 07/45] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD " Andreas Gruenbacher
2015-04-24 11:04 ` Andreas Gruenbacher [this message]
2015-04-24 11:04 ` [RFC v3 10/45] richacl: In-memory representation and helper functions Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 11/45] richacl: Permission mapping functions Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 12/45] richacl: Compute maximum file masks from an acl Andreas Gruenbacher
2015-05-12 21:44 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 15/45] vfs: Cache base_acl objects in inodes Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 16/45] vfs: Cache richacl in struct inode Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 17/45] richacl: Create-time inheritance Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 18/45] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 19/45] richacl: Also recognize nontrivial mode-equivalent acls Andreas Gruenbacher
2015-05-14 19:28 ` J. Bruce Fields
[not found] ` <20150514192806.GG12861-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-05-15 20:04 ` J. Bruce Fields
[not found] ` <5e9ee3b123b3d648487cd18dc906b6a2cd23085b.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-15 20:51 ` J. Bruce Fields
2015-05-27 9:24 ` Andreas Grünbacher
2015-05-27 15:06 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 20/45] richacl: Automatic Inheritance Andreas Gruenbacher
[not found] ` <28e2cd75064ff56bad897b6f69356f4fb15b8128.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-13 18:01 ` Frank Filz
2015-05-13 20:22 ` Andreas Grünbacher
2015-05-13 20:28 ` Jeremy Allison
2015-05-13 20:47 ` Andreas Grünbacher
2015-05-13 20:55 ` Jeremy Allison
2015-05-13 21:15 ` Andreas Grünbacher
[not found] ` <CAHpGcMLBb+s7iSv9SN1eRX-46VU_wnbGX1nXrNkuaYVp8v0jYw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-13 20:38 ` Frank Filz
2015-05-13 21:05 ` Andreas Grünbacher
2015-05-13 22:56 ` Frank Filz
2015-05-13 23:52 ` Andreas Grünbacher
2015-05-14 15:09 ` J. Bruce Fields
[not found] ` <20150514150925.GE12861-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-05-18 20:39 ` Andreas Grünbacher
[not found] ` <CAHpGcMLK+=Sd+5xS5bsq+7FffiKQAH_t53yAMpiukeVh1JB6Mw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-18 20:43 ` J. Bruce Fields
[not found] ` <cover.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-04-24 11:04 ` [RFC v3 08/45] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 13/45] richacl: Update the file masks in chmod() Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 14/45] richacl: Permission check algorithm Andreas Gruenbacher
2015-05-22 21:08 ` J. Bruce Fields
2015-05-27 11:25 ` Andreas Grünbacher
2015-05-27 15:05 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 21/45] richacl: xattr mapping functions Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 22/45] vfs: Add richacl permission checking Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 25/45] richacl: acl editing helper functions Andreas Gruenbacher
[not found] ` <a74bc8fdb5d8ee5bdd5defad9729d17211266079.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-15 21:33 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 39/45] nfs3: Return posix acl encode errors Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 23/45] ext4: Add richacl support Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 24/45] ext4: Add richacl feature flag Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 26/45] richacl: Move everyone@ aces down the acl Andreas Gruenbacher
2015-05-18 21:20 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 27/45] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 28/45] richacl: Isolate the owner and group classes Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 29/45] richacl: Apply the file masks to a richacl Andreas Gruenbacher
[not found] ` <35b73e9515f2395c8595cbbf4ea7b92216e5e2a0.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-26 21:56 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 30/45] richacl: Create richacl from mode values Andreas Gruenbacher
[not found] ` <b435787dd651572f42984f9dec2a68cbf38bc7bf.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-28 19:24 ` J. Bruce Fields
2015-05-28 19:25 ` J. Bruce Fields
[not found] ` <20150528192553.GB31663-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-05-28 19:58 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 31/45] richacl: Create acl with masks applied in richacl_from_mode() Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 32/45] nfsd: Remove dead declarations Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 33/45] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher
[not found] ` <4f0168389120bf67cf69ce4ac7bb8ce878aa0f5d.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-28 19:52 ` J. Bruce Fields
[not found] ` <20150528195205.GC31663-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-05-28 20:28 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 34/45] nfsd: Use richacls as internal acl representation Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 35/45] nfsd: Add richacl support Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 36/45] NFSv4: Fix GETATTR bitmap verification Andreas Gruenbacher
[not found] ` <8d601ee8babe5239b7926542c713c58502b15e35.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-28 20:33 ` J. Bruce Fields
2015-05-28 21:15 ` Andreas Grünbacher
[not found] ` <20150528203332.GD31663-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-05-28 20:50 ` Trond Myklebust
[not found] ` <CAHQdGtTe9RfxxGU+UzxnT8A1BmhtPQaOB=g6wXpvmHTu6Ho=Jg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-28 21:05 ` Andreas Grünbacher
[not found] ` <CAHpGcM+=ydzFDeTc4_1F9dYbtJ+D_mGVLKZOYkvvRjT7ZHd_xA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-28 21:40 ` Trond Myklebust
[not found] ` <CAHQdGtQKRokdRRuGmU-qD3fxOUE8cYrtb=sNcYenVT8M8XAmYA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-28 21:55 ` Trond Myklebust
[not found] ` <CAHQdGtRaq93Rk1ZNn7tqBPJVWhWwUGS7k1XzdC3etfna4kLtDg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-28 22:09 ` Andreas Grünbacher
[not found] ` <CAHpGcMLQGc4HUZEDRKAv2yaH7wwSBBO_jrMA6+=AQ6hb=WrNUg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-28 22:24 ` Trond Myklebust
2015-05-28 22:28 ` Andreas Grünbacher
2015-05-28 21:28 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 37/45] nfs/sunrpc: No more encode and decode function pointer casting Andreas Gruenbacher
2015-05-28 23:11 ` Trond Myklebust
2015-05-28 23:40 ` Andreas Grünbacher
[not found] ` <CAHpGcMKn1khdNTk=MFS7vFgLCHmxX2fVTJanertXT+Zj_BnAKA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-29 0:37 ` Trond Myklebust
[not found] ` <CAHQdGtRKLnMbB6Z5w7MCnONujHH2uBnx4VUrTL1GGfWTNwurRQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-05-29 15:30 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 38/45] nfs/sunrpc: Return status code from encode functions Andreas Gruenbacher
[not found] ` <9c755df47acdef7f6a1d0195af888dafb7d3e7bf.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-28 23:39 ` Trond Myklebust
2015-04-24 11:04 ` [RFC v3 40/45] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 41/45] rpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher
[not found] ` <4bf77d045d2bd3494c695229cd0505b7002cc9a2.1429868795.git.agruenba-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-05-28 23:24 ` Trond Myklebust
2015-05-29 15:46 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 42/45] nfs: Add richacl support Andreas Gruenbacher
2015-05-28 23:06 ` Trond Myklebust
2015-05-28 23:29 ` Andreas Grünbacher
2015-05-29 13:15 ` Trond Myklebust
2015-05-29 15:00 ` Andreas Grünbacher
2015-05-29 15:24 ` Trond Myklebust
2015-05-29 15:45 ` Andreas Grünbacher
2015-05-29 15:54 ` Trond Myklebust
2015-05-29 15:54 ` Frank Filz
2016-06-23 16:37 ` Weston Andros Adamson
2016-06-23 17:15 ` Frank Filz
2016-07-15 8:00 ` Andreas Grünbacher
2015-04-24 11:04 ` [RFC v3 43/45] uapi/nfs: Add NFSv4.1 ACL definitions Andreas Gruenbacher
2015-05-29 14:57 ` J. Bruce Fields
2015-04-24 11:04 ` [RFC v3 44/45] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher
2015-04-24 11:04 ` [RFC v3 45/45] nfs: " Andreas Gruenbacher
2015-05-23 15:50 ` [RFC v3 00/45] Richacls Jeremy Allison
2015-05-23 15:56 ` Andreas Grünbacher
2015-06-25 20:03 ` Stefan (metze) Metzmacher
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