]> wimlib.net Git - wimlib/blobdiff - src/dentry.c
Avoid passing NULL as memcpy source (undefined behavior)
[wimlib] / src / dentry.c
index a45bdf89522dfc0d3a2d7c84e8a9ee3c6873d519..caa3a51b4b86fb0d98e84f103781cc0274499294 100644 (file)
@@ -358,7 +358,8 @@ dentry_out_total_length(const struct wim_dentry *dentry)
                                        dentry->d_short_name_nbytes);
        len = ALIGN(len, 8);
 
-       len += ALIGN(inode->i_extra_size, 8);
+       if (inode->i_extra)
+               len += ALIGN(inode->i_extra->size, 8);
 
        if (!(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
                /*
@@ -503,7 +504,8 @@ calculate_dentry_full_path(struct wim_dentry *dentry)
        d = dentry;
        do {
                p -= d->d_name_nbytes / sizeof(utf16lechar);
-               memcpy(p, d->d_name, d->d_name_nbytes);
+               if (d->d_name_nbytes)
+                       memcpy(p, d->d_name, d->d_name_nbytes);
                *--p = cpu_to_le16(WIM_PATH_SEPARATOR);
                d = d->d_parent;  /* assumes d == d->d_parent for root  */
        } while (!dentry_is_root(d));
@@ -982,19 +984,6 @@ new_filler_directory(struct wim_dentry **dentry_ret)
        return 0;
 }
 
-static int
-dentry_clear_inode_visited(struct wim_dentry *dentry, void *_ignore)
-{
-       dentry->d_inode->i_visited = 0;
-       return 0;
-}
-
-void
-dentry_tree_clear_inode_visited(struct wim_dentry *root)
-{
-       for_dentry_in_tree(root, dentry_clear_inode_visited, NULL);
-}
-
 /*
  * Free a WIM dentry.
  *
@@ -1200,10 +1189,12 @@ read_extra_data(const u8 *p, const u8 *end, struct wim_inode *inode)
                p++;
 
        if (unlikely(p < end)) {
-               inode->i_extra = memdup(p, end - p);
+               inode->i_extra = MALLOC(sizeof(struct wim_inode_extra) +
+                                       end - p);
                if (!inode->i_extra)
                        return WIMLIB_ERR_NOMEM;
-               inode->i_extra_size = end - p;
+               inode->i_extra->size = end - p;
+               memcpy(inode->i_extra->data, p, end - p);
        }
        return 0;
 }
@@ -1240,6 +1231,12 @@ assign_stream_types_encrypted(struct wim_inode *inode)
  * There will be an unnamed data stream, a reparse point stream, or both an
  * unnamed data stream and a reparse point stream.  In addition, there may be
  * named data streams.
+ *
+ * NOTE: if the file has a reparse point stream or at least one named data
+ * stream, then WIMGAPI puts *all* streams in the extra stream entries and
+ * leaves the default stream hash zeroed.  wimlib now does the same.  However,
+ * for input we still support the default hash field being used, since wimlib
+ * used to use it and MS software is somewhat accepting of it as well.
  */
 static void
 assign_stream_types_unencrypted(struct wim_inode *inode)
@@ -1254,7 +1251,10 @@ assign_stream_types_unencrypted(struct wim_inode *inode)
                if (stream_is_named(strm)) {
                        /* Named data stream  */
                        strm->stream_type = STREAM_TYPE_DATA;
-               } else if (!is_zero_hash(strm->_stream_hash)) {
+               } else if (i != 0 || !is_zero_hash(strm->_stream_hash)) {
+                       /* Unnamed stream in the extra stream entries, OR the
+                        * default stream in the dentry provided that it has a
+                        * nonzero hash.  */
                        if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
                            !found_reparse_point_stream) {
                                found_reparse_point_stream = true;
@@ -1263,17 +1263,21 @@ assign_stream_types_unencrypted(struct wim_inode *inode)
                                found_unnamed_data_stream = true;
                                strm->stream_type = STREAM_TYPE_DATA;
                        }
-               } else {
-                       /* If no stream name is specified and the hash is zero,
-                        * then remember this stream for later so that we can
-                        * assign it to the unnamed data stream if we don't find
-                        * a better candidate.  */
+               } else if (!unnamed_stream_with_zero_hash) {
                        unnamed_stream_with_zero_hash = strm;
                }
        }
 
-       if (!found_unnamed_data_stream && unnamed_stream_with_zero_hash != NULL)
-               unnamed_stream_with_zero_hash->stream_type = STREAM_TYPE_DATA;
+       if (unnamed_stream_with_zero_hash) {
+               int type = STREAM_TYPE_UNKNOWN;
+               if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
+                   !found_reparse_point_stream) {
+                       type = STREAM_TYPE_REPARSE_POINT;
+               } else if (!found_unnamed_data_stream) {
+                       type = STREAM_TYPE_DATA;
+               }
+               unnamed_stream_with_zero_hash->stream_type = type;
+       }
 }
 
 /*
@@ -1394,7 +1398,7 @@ read_dentry(const u8 * restrict buf, size_t buf_len,
        u64 calculated_size;
        int ret;
 
-       BUILD_BUG_ON(sizeof(struct wim_dentry_on_disk) != WIM_DENTRY_DISK_SIZE);
+       STATIC_ASSERT(sizeof(struct wim_dentry_on_disk) == WIM_DENTRY_DISK_SIZE);
 
        /* Before reading the whole dentry, we need to read just the length.
         * This is because a dentry of length 8 (that is, just the length field)
@@ -1547,21 +1551,14 @@ dentry_is_dot_or_dotdot(const struct wim_dentry *dentry)
 
 static int
 read_dentry_tree_recursive(const u8 * restrict buf, size_t buf_len,
-                          struct wim_dentry * restrict dir)
+                          struct wim_dentry * restrict dir, unsigned depth)
 {
        u64 cur_offset = dir->d_subdir_offset;
 
-       /* Check for cyclic directory structure, which would cause infinite
-        * recursion if not handled.  */
-       for (struct wim_dentry *d = dir->d_parent;
-            !dentry_is_root(d); d = d->d_parent)
-       {
-               if (unlikely(d->d_subdir_offset == cur_offset)) {
-                       ERROR("Cyclic directory structure detected: children "
-                             "of \"%"TS"\" coincide with children of \"%"TS"\"",
-                             dentry_full_path(dir), dentry_full_path(d));
-                       return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
-               }
+       /* Disallow extremely deep or cyclic directory structures  */
+       if (unlikely(depth >= 16384)) {
+               ERROR("Directory structure too deep!");
+               return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
        }
 
        for (;;) {
@@ -1614,7 +1611,8 @@ read_dentry_tree_recursive(const u8 * restrict buf, size_t buf_len,
                        if (likely(dentry_is_directory(child))) {
                                ret = read_dentry_tree_recursive(buf,
                                                                 buf_len,
-                                                                child);
+                                                                child,
+                                                                depth + 1);
                                if (ret)
                                        return ret;
                        } else {
@@ -1655,8 +1653,6 @@ read_dentry_tree(const u8 *buf, size_t buf_len,
        int ret;
        struct wim_dentry *root;
 
-       DEBUG("Reading dentry tree (root_offset=%"PRIu64")", root_offset);
-
        ret = read_dentry(buf, buf_len, &root_offset, &root);
        if (ret)
                return ret;
@@ -1677,7 +1673,7 @@ read_dentry_tree(const u8 *buf, size_t buf_len,
                }
 
                if (likely(root->d_subdir_offset != 0)) {
-                       ret = read_dentry_tree_recursive(buf, buf_len, root);
+                       ret = read_dentry_tree_recursive(buf, buf_len, root, 0);
                        if (ret)
                                goto err_free_dentry_tree;
                }
@@ -1782,9 +1778,9 @@ write_dentry(const struct wim_dentry * restrict dentry, u8 * restrict p)
        while ((uintptr_t)p & 7)
                *p++ = 0;
 
-       if (inode->i_extra_size) {
+       if (inode->i_extra) {
                /* Extra tagged items --- not usually present.  */
-               p = mempcpy(p, inode->i_extra, inode->i_extra_size);
+               p = mempcpy(p, inode->i_extra->data, inode->i_extra->size);
 
                /* Align to 8-byte boundary */
                while ((uintptr_t)p & 7)
@@ -1903,10 +1899,6 @@ write_dir_dentries(struct wim_dentry *dir, void *_pp)
 u8 *
 write_dentry_tree(struct wim_dentry *root, u8 *p)
 {
-       DEBUG("Writing dentry tree.");
-
-       wimlib_assert(root != NULL);
-
        /* write root dentry and end-of-directory entry following it */
        p = write_dentry(root, p);
        *(u64*)p = 0;