bpf: fix two bugs in verification logic when accessing 'ctx' pointer

[firefly-linux-kernel-4.4.55.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 6218e62a0534486b9a4919b11e6ba07da115a583..76fb76a0818bc274fc67b2d87b582db6690d62a6 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2038,19 +2038,6 @@ static int filename_lookup(int dfd, struct filename *name,
        return retval;
 }
 
-static int do_path_lookup(int dfd, const char *name,
-                               unsigned int flags, struct nameidata *nd)
-{
-       struct filename *filename = getname_kernel(name);
-       int retval = PTR_ERR(filename);
-
-       if (!IS_ERR(filename)) {
-               retval = filename_lookup(dfd, filename, flags, nd);
-               putname(filename);
-       }
-       return retval;
-}
-
 /* does lookup, returns the object with parent locked */
 struct dentry *kern_path_locked(const char *name, struct path *path)
 {
@@ -2088,9 +2075,15 @@ out:
 int kern_path(const char *name, unsigned int flags, struct path *path)
 {
        struct nameidata nd;
-       int res = do_path_lookup(AT_FDCWD, name, flags, &nd);
-       if (!res)
-               *path = nd.path;
+       struct filename *filename = getname_kernel(name);
+       int res = PTR_ERR(filename);
+
+       if (!IS_ERR(filename)) {
+               res = filename_lookup(AT_FDCWD, filename, flags, &nd);
+               putname(filename);
+               if (!res)
+                       *path = nd.path;
+       }
        return res;
 }
 EXPORT_SYMBOL(kern_path);
@@ -2107,15 +2100,22 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
                    const char *name, unsigned int flags,
                    struct path *path)
 {
-       struct nameidata nd;
-       int err;
-       nd.root.dentry = dentry;
-       nd.root.mnt = mnt;
+       struct filename *filename = getname_kernel(name);
+       int err = PTR_ERR(filename);
+
        BUG_ON(flags & LOOKUP_PARENT);
-       /* the first argument of do_path_lookup() is ignored with LOOKUP_ROOT */
-       err = do_path_lookup(AT_FDCWD, name, flags | LOOKUP_ROOT, &nd);
-       if (!err)
-               *path = nd.path;
+
+       /* the first argument of filename_lookup() is ignored with LOOKUP_ROOT */
+       if (!IS_ERR(filename)) {
+               struct nameidata nd;
+               nd.root.dentry = dentry;
+               nd.root.mnt = mnt;
+               err = filename_lookup(AT_FDCWD, filename,
+                                     flags | LOOKUP_ROOT, &nd);
+               if (!err)
+                       *path = nd.path;
+               putname(filename);
+       }
        return err;
 }
 EXPORT_SYMBOL(vfs_path_lookup);
@@ -2137,9 +2137,7 @@ static struct dentry *lookup_hash(struct nameidata *nd)
  * @len:       maximum length @len should be interpreted to
  *
  * Note that this routine is purely a helper for filesystem usage and should
- * not be called by generic code.  Also note that by using this function the
- * nameidata argument is passed to the filesystem methods and a filesystem
- * using this helper needs to be prepared for that.
+ * not be called by generic code.
  */
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {