[PATCH] move executable checking into ->permission()

For execute permission on a regular files we need to check if file has
any execute bits at all, regardless of capabilites.

This check is normally performed by generic_permission() but was also
added to the case when the filesystem defines its own ->permission()
method.  In the latter case the filesystem should be responsible for
performing this check.

Move the check from inode_permission() inside filesystems which are
not calling generic_permission().

Create a helper function execute_ok() that returns true if the inode
is a directory or if any execute bits are present in i_mode.

Also fix up the following code:

 - coda control file is never executable
 - sysctl files are never executable
 - hfs_permission seems broken on MAY_EXEC, remove
 - hfsplus_permission is eqivalent to generic_permission(), remove

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 4 insertions, 17 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 9e2a534383d9..09ce58e49e72 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -212,8 +212,7 @@ int generic_permission(struct inode *inode, int mask,
          * Read/write DACs are always overridable.
          * Executable DACs are overridable if at least one exec bit is set.
          */
-        if (!(mask & MAY_EXEC) ||
-            (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
+        if (!(mask & MAY_EXEC) || execute_ok(inode))
                 if (capable(CAP_DAC_OVERRIDE))
                         return 0;
 
@@ -249,23 +248,11 @@ int inode_permission(struct inode *inode, int mask)
         }
 
         /* Ordinary permission routines do not understand MAY_APPEND. */
-        if (inode->i_op && inode->i_op->permission) {
+        if (inode->i_op && inode->i_op->permission)
                 retval = inode->i_op->permission(inode, mask);
-                if (!retval) {
-                        /*
-                         * Exec permission on a regular file is denied if none
-                         * of the execute bits are set.
-                         *
-                         * This check should be done by the ->permission()
-                         * method.
-                         */
-                        if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
-                            !(inode->i_mode & S_IXUGO))
-                                return -EACCES;
-                }
-        } else {
+        else
                 retval = generic_permission(inode, mask, NULL);
-        }
+
         if (retval)
                 return retval;