sanitize pathname component hash calculation

Lift it to lookup_one_len() and link_path_walk() resp. into the
same place where we calculated default hash function of the same
name.

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

1 files changed, 19 insertions, 23 deletions

diff --git a/fs/namei.c b/fs/namei.c
index f6f3ef47bc74..d1a5dfeaf999 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1217,16 +1217,6 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
         int err;
 
         /*
-         * See if the low-level filesystem might want
-         * to use its own hash..
-         */
-        if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
-                err = parent->d_op->d_hash(parent, nd->inode, name);
-                if (err < 0)
-                        return err;
-        }
-
-        /*
          * Rename seqlock is not required here because in the off chance
          * of a false negative due to a concurrent rename, we're going to
          * do the non-racy lookup, below.
@@ -1414,8 +1404,16 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                         case 1:
                                 type = LAST_DOT;
                 }
-                if (likely(type == LAST_NORM))
+                if (likely(type == LAST_NORM)) {
+                        struct dentry *parent = nd->path.dentry;
                         nd->flags &= ~LOOKUP_JUMPED;
+                        if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
+                                err = parent->d_op->d_hash(parent, nd->inode,
+                                                           &this);
+                                if (err < 0)
+                                        break;
+                        }
+                }
 
                 /* remove trailing slashes? */
                 if (!c)
@@ -1723,17 +1721,6 @@ static struct dentry *__lookup_hash(struct qstr *name,
                 return ERR_PTR(err);
 
         /*
-         * See if the low-level filesystem might want
-         * to use its own hash..
-         */
-        if (base->d_flags & DCACHE_OP_HASH) {
-                err = base->d_op->d_hash(base, inode, name);
-                dentry = ERR_PTR(err);
-                if (err < 0)
-                        goto out;
-        }
-
-        /*
          * Don't bother with __d_lookup: callers are for creat as
          * well as unlink, so a lot of the time it would cost
          * a double lookup.
@@ -1745,7 +1732,7 @@ static struct dentry *__lookup_hash(struct qstr *name,
 
         if (!dentry)
                 dentry = d_alloc_and_lookup(base, name, nd);
-out:
+
         return dentry;
 }
 
@@ -1791,6 +1778,15 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
                 hash = partial_name_hash(c, hash);
         }
         this.hash = end_name_hash(hash);
+        /*
+         * See if the low-level filesystem might want
+         * to use its own hash..
+         */
+        if (base->d_flags & DCACHE_OP_HASH) {
+                int err = base->d_op->d_hash(base, base->d_inode, &this);
+                if (err < 0)
+                        return ERR_PTR(err);
+        }
 
         return __lookup_hash(&this, base, NULL);
 }