From: Andreas Gruenbacher <agrue...@redhat.com>

Hook the richacl permission checking function into the vfs.

Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
 fs/namei.c     | 51 +++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/posix_acl.c |  6 +++---
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 2eab19e..3822b5e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -35,6 +35,7 @@
 #include <linux/fs_struct.h>
 #include <linux/posix_acl.h>
 #include <linux/hash.h>
+#include <linux/richacl.h>
 #include <asm/uaccess.h>
 
 #include "internal.h"
@@ -255,7 +256,40 @@ void putname(struct filename *name)
                __putname(name);
 }
 
-static int check_acl(struct inode *inode, int mask)
+static int check_richacl(struct inode *inode, int mask)
+{
+#ifdef CONFIG_FS_RICHACL
+       struct richacl *acl;
+
+       if (mask & MAY_NOT_BLOCK) {
+               acl = get_cached_richacl_rcu(inode);
+               if (!acl)
+                       goto no_acl;
+               /* no ->get_richacl() calls in RCU mode... */
+               if (acl == ACL_NOT_CACHED)
+                       return -ECHILD;
+               return richacl_permission(inode, acl, mask & ~MAY_NOT_BLOCK);
+       }
+
+       acl = get_richacl(inode);
+       if (IS_ERR(acl))
+               return PTR_ERR(acl);
+       if (acl) {
+               int error = richacl_permission(inode, acl, mask);
+               richacl_put(acl);
+               return error;
+       }
+no_acl:
+#endif
+       if (mask & (MAY_DELETE_SELF | MAY_TAKE_OWNERSHIP |
+                   MAY_CHMOD | MAY_SET_TIMES)) {
+               /* File permission bits cannot grant this. */
+               return -EACCES;
+       }
+       return -EAGAIN;
+}
+
+static int check_posix_acl(struct inode *inode, int mask)
 {
 #ifdef CONFIG_FS_POSIX_ACL
        struct posix_acl *acl;
@@ -290,11 +324,24 @@ static int acl_permission_check(struct inode *inode, int 
mask)
 {
        unsigned int mode = inode->i_mode;
 
+       /*
+        * With POSIX ACLs, the (mode & S_IRWXU) bits exactly match the owner
+        * permissions, and we can skip checking posix acls for the owner.
+        * With richacls, the owner may be granted fewer permissions than the
+        * mode bits seem to suggest (for example, append but not write), and
+        * we always need to check the richacl.
+        */
+
+       if (IS_RICHACL(inode)) {
+               int error = check_richacl(inode, mask);
+               if (error != -EAGAIN)
+                       return error;
+       }
        if (likely(uid_eq(current_fsuid(), inode->i_uid)))
                mode >>= 6;
        else {
                if (IS_POSIXACL(inode) && (mode & S_IRWXG)) {
-                       int error = check_acl(inode, mask);
+                       int error = check_posix_acl(inode, mask);
                        if (error != -EAGAIN)
                                return error;
                }
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 1d766a5..3459bd5 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -100,13 +100,13 @@ struct posix_acl *get_acl(struct inode *inode, int type)
 {
        struct posix_acl *acl;
 
+       if (!IS_POSIXACL(inode))
+               return NULL;
+
        acl = get_cached_acl(inode, type);
        if (acl != ACL_NOT_CACHED)
                return acl;
 
-       if (!IS_POSIXACL(inode))
-               return NULL;
-
        /*
         * A filesystem can force a ACL callback by just never filling the
         * ACL cache. But normally you'd fill the cache either at inode
-- 
2.5.0

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