Code to handle some weird siutations and bad WIMs
authorEric Biggers <ebiggers3@gmail.com>
Fri, 24 Aug 2012 00:44:42 +0000 (19:44 -0500)
committerEric Biggers <ebiggers3@gmail.com>
Fri, 24 Aug 2012 00:44:42 +0000 (19:44 -0500)
- read_lookup_table():  It is now an error if uncompressed resources have
  different compressed and uncompressed size.
- read_lookup_table(): It is now an error if two lookup table entries have the
  same SHA1 message digest.
- write_metadata_resource(): Append 20 random bytes to the end of the metadata
  resource to make the metadata resource unique even if we capture exactly the
  same image again.

src/lookup_table.c
src/resource.c
src/util.c
src/wimlib.h

index 0c6a55fcccb9463c8092fda7269ef09b048745a8..0546f958a3108f41dc2b3dffc884a576567b8ea3 100644 (file)
@@ -197,7 +197,7 @@ int read_lookup_table(WIMStruct *w)
 
        while (num_entries--) {
                const u8 *p;
-               struct lookup_table_entry *cur_entry;
+               struct lookup_table_entry *cur_entry, *duplicate_entry;
 
                if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
                        if (feof(w->fp)) {
@@ -221,7 +221,31 @@ int read_lookup_table(WIMStruct *w)
                p = get_u16(p, &cur_entry->part_number);
                p = get_u32(p, &cur_entry->refcnt);
                p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
+
+               duplicate_entry = __lookup_resource(table, cur_entry->hash);
+               if (duplicate_entry) {
+                       ERROR("The WIM lookup table contains two entries with the "
+                             "same SHA1 message digest!");
+                       ERROR("The first entry is:");
+                       print_lookup_table_entry(duplicate_entry);
+                       ERROR("The second entry is:");
+                       print_lookup_table_entry(cur_entry);
+                       ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
+                       goto out;
+               }
                lookup_table_insert(table, cur_entry);
+
+               if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
+                   && (cur_entry->resource_entry.size !=
+                     cur_entry->resource_entry.original_size))
+               {
+                       ERROR("Found uncompressed resource with original size "
+                             "not the same as compressed size");
+                       ERROR("The lookup table entry for the resource is as follows:");
+                       print_lookup_table_entry(cur_entry);
+                       ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
+                       goto out;
+               }
        }
        DEBUG("Done reading lookup table.");
        w->lookup_table = table;
index 4f093622f9e64d356484015f8b45db1cc33635b9..2dde8d55578435c39b64151746a6c1e1dbe88abd 100644 (file)
@@ -431,18 +431,9 @@ int read_wim_resource(const struct lookup_table_entry *lte, u8 buf[],
                wimlib_assert(lte->wim->fp);
                ctype = wim_resource_compression_type(lte);
 
-               /* XXX This check should be moved elsewhere */
-               if (ctype == WIM_COMPRESSION_TYPE_NONE &&
-                    lte->resource_entry.original_size !=
-                     lte->resource_entry.size) {
-                       ERROR("WIM resource at offset %"PRIu64", size %"PRIu64
-                             "has an original size of %"PRIu64", but is "
-                             "uncompressed",
-                             lte->resource_entry.offset,
-                             lte->resource_entry.size,
-                             lte->resource_entry.original_size);
-                       return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
-               }
+               wimlib_assert(ctype != WIM_COMPRESSION_TYPE_NONE ||
+                             (lte->resource_entry.original_size ==
+                              lte->resource_entry.size));
 
                if (raw || ctype == WIM_COMPRESSION_TYPE_NONE)
                        return read_uncompressed_resource(lte->wim->fp,
@@ -1178,9 +1169,18 @@ int write_metadata_resource(WIMStruct *w)
        int ret;
        u64 subdir_offset;
        struct dentry *root;
-       struct lookup_table_entry *lte;
+       struct lookup_table_entry *lte, *duplicate_lte;
        u64 metadata_original_size;
 
+       /* 
+        * We append 20 random bytes to the metadata resource so that we don't
+        * have identical metadata resources if we happen to append exactly the
+        * same image twice without any changes in timestamps.  If this were to
+        * happen, it would cause confusion about the number and order of images
+        * in the WIM.
+        */
+       const unsigned random_tail_len = 20;
+
        DEBUG("Writing metadata resource for image %d", w->current_image);
 
        root = wim_root_dentry(w);
@@ -1191,7 +1191,7 @@ int write_metadata_resource(WIMStruct *w)
        else
                subdir_offset = 8 + root->length + 8;
        calculate_subdir_offsets(root, &subdir_offset);
-       metadata_original_size = subdir_offset;
+       metadata_original_size = subdir_offset + random_tail_len;
        buf = MALLOC(metadata_original_size);
        if (!buf) {
                ERROR("Failed to allocate %"PRIu64" bytes for "
@@ -1203,7 +1203,8 @@ int write_metadata_resource(WIMStruct *w)
 
        DEBUG("Writing dentry tree.");
        p = write_dentry_tree(root, p);
-       wimlib_assert(p - buf == metadata_original_size);
+       randomize_byte_array(p, random_tail_len);
+       wimlib_assert(p - buf + random_tail_len == metadata_original_size);
 
        lte = wim_metadata_lookup_table_entry(w);
 
@@ -1212,11 +1213,12 @@ int write_metadata_resource(WIMStruct *w)
                                             wimlib_get_compression_type(w),
                                             &lte->output_resource_entry,
                                             lte->hash);
-
        lookup_table_unlink(w->lookup_table, lte);
        lookup_table_insert(w->lookup_table, lte);
+       wimlib_assert(lte->out_refcnt == 0);
        lte->out_refcnt++;
        lte->output_resource_entry.flags |= WIM_RESHDR_FLAG_METADATA;
+out:
        FREE(buf);
        return ret;
 }
index e5b0d9e7ad586728387a06dd18f7c1f5515707f6..985d11b875c90352233d73ecbd9f1bdcc918bdd0 100644 (file)
@@ -141,6 +141,8 @@ static const char *error_strings[] = {
                = "Tried to select an image that does not exist in the WIM",
        [WIMLIB_ERR_INVALID_INTEGRITY_TABLE] 
                = "The WIM's integrity table is invalid",
+       [WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY]
+               = "An entry in the WIM's lookup table is invalid",
        [WIMLIB_ERR_INVALID_PARAM] 
                = "An invalid parameter was given",
        [WIMLIB_ERR_INVALID_RESOURCE_HASH]
index 73f5c32af31404fcc3bed7a1cf7c016348d11ea8..9aa8a05a61b803a91142f6884e6e0b43cee867b4 100644 (file)
@@ -328,6 +328,7 @@ enum wimlib_error_code {
        WIMLIB_ERR_INVALID_HEADER_SIZE,
        WIMLIB_ERR_INVALID_IMAGE,
        WIMLIB_ERR_INVALID_INTEGRITY_TABLE,
+       WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY,
        WIMLIB_ERR_INVALID_PARAM,
        WIMLIB_ERR_INVALID_RESOURCE_HASH,
        WIMLIB_ERR_INVALID_RESOURCE_SIZE,