[PATCH] sanitize ->permission() prototype

* kill nameidata * argument; map the 3 bits in ->flags anybody cares
  about to new MAY_... ones and pass with the mask.
* kill redundant gfs2_iop_permission()
* sanitize ecryptfs_permission()
* fix remaining places where ->permission() instances might barf on new
  MAY_... found in mask.

The obvious next target in that direction is permission(9)

folded fix for nfs_permission() breakage from Miklos Szeredi <mszeredi@suse.cz>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 6 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 3b26a240ade9..46af98ed136b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -185,6 +185,8 @@ int generic_permission(struct inode *inode, int mask,
 {
         umode_t                 mode = inode->i_mode;
 
+        mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
+
         if (current->fsuid == inode->i_uid)
                 mode >>= 6;
         else {
@@ -203,7 +205,7 @@ int generic_permission(struct inode *inode, int mask,
         /*
          * If the DACs are ok we don't need any capability check.
          */
-        if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask))
+        if ((mask & ~mode) == 0)
                 return 0;
 
  check_capabilities:
@@ -228,7 +230,7 @@ int generic_permission(struct inode *inode, int mask,
 
 int permission(struct inode *inode, int mask, struct nameidata *nd)
 {
-        int retval, submask;
+        int retval;
         struct vfsmount *mnt = NULL;
 
         if (nd)
@@ -261,9 +263,17 @@ int permission(struct inode *inode, int mask, struct nameidata *nd)
         }
 
         /* Ordinary permission routines do not understand MAY_APPEND. */
-        submask = mask & ~MAY_APPEND;
         if (inode->i_op && inode->i_op->permission) {
-                retval = inode->i_op->permission(inode, submask, nd);
+                int extra = 0;
+                if (nd) {
+                        if (nd->flags & LOOKUP_ACCESS)
+                                extra |= MAY_ACCESS;
+                        if (nd->flags & LOOKUP_CHDIR)
+                                extra |= MAY_CHDIR;
+                        if (nd->flags & LOOKUP_OPEN)
+                                extra |= MAY_OPEN;
+                }
+                retval = inode->i_op->permission(inode, mask | extra);
                 if (!retval) {
                         /*
                          * Exec permission on a regular file is denied if none
@@ -277,7 +287,7 @@ int permission(struct inode *inode, int mask, struct nameidata *nd)
                                 return -EACCES;
                 }
         } else {
-                retval = generic_permission(inode, submask, NULL);
+                retval = generic_permission(inode, mask, NULL);
         }
         if (retval)
                 return retval;
@@ -286,7 +296,8 @@ int permission(struct inode *inode, int mask, struct nameidata *nd)
         if (retval)
                 return retval;
 
-        return security_inode_permission(inode, mask, nd);
+        return security_inode_permission(inode,
+                        mask & (MAY_READ|MAY_WRITE|MAY_EXEC), nd);
 }
 
 /**