From: Eric Biggers <ebiggers3@gmail.com>
Date: Wed, 25 Mar 2015 01:46:01 +0000 (-0500)
Subject: Limit exposure of dentry and inode creation
X-Git-Tag: v1.8.1~68
X-Git-Url: https://wimlib.net/git/?p=wimlib;a=commitdiff_plain;h=43a26b833482fc019c7aeee95656b8f2f3077db7

Limit exposure of dentry and inode creation

- Don't allow creating d_inode=NULL dentries outside of dentry.c
- Don't allow creating i_nlink=0 inodes
---

diff --git a/include/wimlib/dentry.h b/include/wimlib/dentry.h
index 241dc56d..cb0f330b 100644
--- a/include/wimlib/dentry.h
+++ b/include/wimlib/dentry.h
@@ -231,13 +231,12 @@ extern tchar *
 dentry_full_path(struct wim_dentry *dentry);
 
 extern int
-new_dentry(const tchar *name, struct wim_dentry **dentry_ret);
+new_dentry_with_new_inode(const tchar *name, bool set_timestamps,
+			  struct wim_dentry **dentry_ret);
 
 extern int
-new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret);
-
-extern int
-new_dentry_with_timeless_inode(const tchar *name, struct wim_dentry **dentry_ret);
+new_dentry_with_existing_inode(const tchar *name, struct wim_inode *inode,
+			       struct wim_dentry **dentry_ret);
 
 extern void
 dentry_tree_clear_inode_visited(struct wim_dentry *root);
diff --git a/include/wimlib/inode.h b/include/wimlib/inode.h
index 28285b2b..1818d108 100644
--- a/include/wimlib/inode.h
+++ b/include/wimlib/inode.h
@@ -281,10 +281,7 @@ struct wim_inode {
 #define FILE_ATTRIBUTE_VIRTUAL             0x00010000
 
 extern struct wim_inode *
-new_inode(void) _malloc_attribute;
-
-extern struct wim_inode *
-new_timeless_inode(void) _malloc_attribute;
+new_inode(struct wim_dentry *dentry, bool set_timestamps);
 
 /* Iterate through each alias of the specified inode.  */
 #define inode_for_each_dentry(dentry, inode) \
diff --git a/src/dentry.c b/src/dentry.c
index 55da50cf..302409f9 100644
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -914,7 +914,7 @@ get_parent_dentry(WIMStruct *wim, const tchar *path,
  * *dentry_ret.  On failure, returns WIMLIB_ERR_NOMEM or an error code resulting
  * from a failed string conversion.
  */
-int
+static int
 new_dentry(const tchar *name, struct wim_dentry **dentry_ret)
 {
 	struct wim_dentry *dentry;
@@ -936,9 +936,12 @@ new_dentry(const tchar *name, struct wim_dentry **dentry_ret)
 	return 0;
 }
 
-static int
-_new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret,
-		       bool timeless)
+/* Like new_dentry(), but also allocate an inode and associate it with the
+ * dentry.  If set_timestamps=true, the timestamps for the inode will be set to
+ * the current time; otherwise, they will be left 0.  */
+int
+new_dentry_with_new_inode(const tchar *name, bool set_timestamps,
+			  struct wim_dentry **dentry_ret)
 {
 	struct wim_dentry *dentry;
 	struct wim_inode *inode;
@@ -948,36 +951,28 @@ _new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret,
 	if (ret)
 		return ret;
 
-	if (timeless)
-		inode = new_timeless_inode();
-	else
-		inode = new_inode();
+	inode = new_inode(dentry, set_timestamps);
 	if (!inode) {
 		free_dentry(dentry);
 		return WIMLIB_ERR_NOMEM;
 	}
 
-	d_associate(dentry, inode);
-
 	*dentry_ret = dentry;
 	return 0;
 }
 
-/* Like new_dentry(), but also allocate an inode and associate it with the
- * dentry.  The timestamps for the inode will be set to the current time.  */
+/* Like new_dentry(), but also associate the new dentry with the specified inode
+ * and acquire a reference to each of the inode's blobs.  */
 int
-new_dentry_with_inode(const tchar *name, struct wim_dentry **dentry_ret)
+new_dentry_with_existing_inode(const tchar *name, struct wim_inode *inode,
+			       struct wim_dentry **dentry_ret)
 {
-	return _new_dentry_with_inode(name, dentry_ret, false);
-}
-
-/* Like new_dentry_with_inode(), but don't bother setting the timestamps for the
- * new inode; instead, just leave them as 0, under the presumption that the
- * caller will set them itself.  */
-int
-new_dentry_with_timeless_inode(const tchar *name, struct wim_dentry **dentry_ret)
-{
-	return _new_dentry_with_inode(name, dentry_ret, true);
+	int ret = new_dentry(name, dentry_ret);
+	if (ret)
+		return ret;
+	d_associate(*dentry_ret, inode);
+	inode_ref_blobs(inode);
+	return 0;
 }
 
 /* Create an unnamed dentry with a new inode for a directory with the default
@@ -988,7 +983,7 @@ new_filler_directory(struct wim_dentry **dentry_ret)
 	int ret;
 	struct wim_dentry *dentry;
 
-	ret = new_dentry_with_inode(NULL, &dentry);
+	ret = new_dentry_with_new_inode(NULL, true, &dentry);
 	if (ret)
 		return ret;
 	/* Leave the inode number as 0; this is allowed for non
@@ -1449,7 +1444,7 @@ read_dentry(const u8 * restrict buf, size_t buf_len,
 		return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
 
 	/* Allocate new dentry structure, along with a preliminary inode.  */
-	ret = new_dentry_with_timeless_inode(NULL, &dentry);
+	ret = new_dentry_with_new_inode(NULL, false, &dentry);
 	if (ret)
 		return ret;
 
diff --git a/src/inode.c b/src/inode.c
index 1114a153..e6da5095 100644
--- a/src/inode.c
+++ b/src/inode.c
@@ -44,32 +44,28 @@
  */
 const utf16lechar NO_STREAM_NAME[1];
 
-/* Allocate a new inode.  Set the timestamps to the current time.  */
+/* Allocate a new inode and associate the specified dentry with it.  */
 struct wim_inode *
-new_inode(void)
+new_inode(struct wim_dentry *dentry, bool set_timestamps)
 {
-	struct wim_inode *inode = new_timeless_inode();
-	if (inode) {
+	struct wim_inode *inode;
+
+	inode = CALLOC(1, sizeof(struct wim_inode));
+	if (!inode)
+		return NULL;
+
+	inode->i_security_id = -1;
+	/*inode->i_nlink = 0;*/
+	inode->i_not_rpfixed = 1;
+	INIT_LIST_HEAD(&inode->i_list);
+	INIT_LIST_HEAD(&inode->i_dentry);
+	if (set_timestamps) {
 		u64 now = now_as_wim_timestamp();
 		inode->i_creation_time = now;
 		inode->i_last_access_time = now;
 		inode->i_last_write_time = now;
 	}
-	return inode;
-}
-
-/* Allocate a new inode.  Leave the timestamps zeroed out.  */
-struct wim_inode *
-new_timeless_inode(void)
-{
-	struct wim_inode *inode = CALLOC(1, sizeof(struct wim_inode));
-	if (inode) {
-		inode->i_security_id = -1;
-		/*inode->i_nlink = 0;*/
-		inode->i_not_rpfixed = 1;
-		INIT_LIST_HEAD(&inode->i_list);
-		INIT_LIST_HEAD(&inode->i_dentry);
-	}
+	d_associate(dentry, inode);
 	return inode;
 }
 
diff --git a/src/inode_table.c b/src/inode_table.c
index f6de4e60..1a1fba69 100644
--- a/src/inode_table.c
+++ b/src/inode_table.c
@@ -96,7 +96,7 @@ inode_table_new_dentry(struct wim_inode_table *table, const tchar *name,
 	if (noshare) {
 		/* File that cannot be hardlinked--- Return a new inode with its
 		 * inode and device numbers left at 0. */
-		ret = new_dentry_with_timeless_inode(name, &dentry);
+		ret = new_dentry_with_new_inode(name, false, &dentry);
 		if (ret)
 			return ret;
 		list_add_tail(&dentry->d_inode->i_list, &table->extra_inodes);
@@ -105,35 +105,25 @@ inode_table_new_dentry(struct wim_inode_table *table, const tchar *name,
 		struct hlist_node *cur;
 
 		/* File that can be hardlinked--- search the table for an
-		 * existing inode matching the inode number and device;
-		 * otherwise create a new inode. */
-		ret = new_dentry(name, &dentry);
-		if (ret)
-			return ret;
-
-		/* Search for an existing inode having the same inode number and
-		 * device number.  */
+		 * existing inode matching the inode number and device.  */
 		pos = hash_u64(hash_u64(ino) + hash_u64(devno)) % table->capacity;
 		hlist_for_each_entry(inode, cur, &table->array[pos], i_hlist) {
 			if (inode->i_ino == ino && inode->i_devno == devno) {
 				/* Found; use the existing inode.  */
-				inode_ref_blobs(inode);
-				goto have_inode;
+				return new_dentry_with_existing_inode(name, inode,
+								      dentry_ret);
 			}
 		}
 
-		/* Create a new inode and insert it into the table.  */
-		inode = new_timeless_inode();
-		if (!inode) {
-			free_dentry(dentry);
-			return WIMLIB_ERR_NOMEM;
-		}
+		/* Not found; create a new inode and add it to the table.  */
+		ret = new_dentry_with_new_inode(name, false, &dentry);
+		if (ret)
+			return ret;
+		inode = dentry->d_inode;
 		inode->i_ino = ino;
 		inode->i_devno = devno;
 		hlist_add_head(&inode->i_hlist, &table->array[pos]);
 		table->num_entries++;
-	have_inode:
-		d_associate(dentry, inode);
 	}
 	*dentry_ret = dentry;
 	return 0;
diff --git a/src/mount_image.c b/src/mount_image.c
index dd6d94c6..10fc61cc 100644
--- a/src/mount_image.c
+++ b/src/mount_image.c
@@ -480,7 +480,7 @@ create_dentry(struct fuse_context *fuse_ctx, const char *path,
 	if (get_dentry_child_with_name(parent, basename, WIMLIB_CASE_SENSITIVE))
 		return -EEXIST;
 
-	if (new_dentry_with_inode(basename, &new_dentry))
+	if (new_dentry_with_new_inode(basename, true, &new_dentry))
 		return -ENOMEM;
 
 	new_inode = new_dentry->d_inode;
@@ -1405,11 +1405,9 @@ wimfs_link(const char *existing_path, const char *new_path)
 	if (get_dentry_child_with_name(dir, new_name, WIMLIB_CASE_SENSITIVE))
 		return -EEXIST;
 
-	if (new_dentry(new_name, &new_alias))
+	if (new_dentry_with_existing_inode(new_name, inode, &new_alias))
 		return -ENOMEM;
 
-	inode_ref_blobs(inode);
-	d_associate(new_alias, inode);
 	dentry_add_child(dir, new_alias);
 	touch_inode(dir->d_inode);
 	return 0;