integrity.c: correctly validate minimum integrity table size

[wimlib] / src / integrity.c

diff --git a/src/integrity.c b/src/integrity.c
index 0d1e13782ffad783e44c2e8b26ec944a6ef50c92..fc9b8859b53e632062821df0afa1682cec97d803 100644 (file)
--- a/src/integrity.c
+++ b/src/integrity.c
@@ -7,7 +7,7 @@
  */
 
 /*
- * Copyright (C) 2012, 2013 Eric Biggers
+ * Copyright (C) 2012-2016 Eric Biggers
  *
  * This file is free software; you can redistribute it and/or modify it under
  * the terms of the GNU Lesser General Public License as published by the Free
@@ -42,7 +42,7 @@
  * information. */
 #define INTEGRITY_CHUNK_SIZE 10485760
 
-/* Only use a different chunk size for compatiblity with an existing integrity
+/* Only use a different chunk size for compatibility with an existing integrity
  * table if the chunk size is between these two numbers. */
 #define INTEGRITY_MIN_CHUNK_SIZE 4096
 #define INTEGRITY_MAX_CHUNK_SIZE 134217728
@@ -113,10 +113,9 @@ read_integrity_table(WIMStruct *wim, u64 num_checked_bytes,
        struct integrity_table *table;
        int ret;
 
-       if (wim->hdr.integrity_table_reshdr.uncompressed_size < 8)
-               goto invalid;
-
-       DEBUG("Reading integrity table.");
+       STATIC_ASSERT(sizeof(struct integrity_table) == 12);
+       if (wim->hdr.integrity_table_reshdr.uncompressed_size < 12)
+               return WIMLIB_ERR_INVALID_INTEGRITY_TABLE;
 
        ret = wim_reshdr_to_data(&wim->hdr.integrity_table_reshdr, wim, &buf);
        if (ret)
@@ -127,24 +126,17 @@ read_integrity_table(WIMStruct *wim, u64 num_checked_bytes,
        table->num_entries = le32_to_cpu(table->num_entries);
        table->chunk_size  = le32_to_cpu(table->chunk_size);
 
-       DEBUG("table->size = %u, table->num_entries = %u, "
-             "table->chunk_size = %u",
-             table->size, table->num_entries, table->chunk_size);
-
        if (table->size != wim->hdr.integrity_table_reshdr.uncompressed_size ||
            table->size != (u64)table->num_entries * SHA1_HASH_SIZE + 12 ||
            table->chunk_size == 0 ||
            table->num_entries != DIV_ROUND_UP(num_checked_bytes, table->chunk_size))
        {
                FREE(table);
-               goto invalid;
+               return WIMLIB_ERR_INVALID_INTEGRITY_TABLE;
        }
 
        *table_ret = table;
        return 0;
-
-invalid:
-       return WIMLIB_ERR_INVALID_INTEGRITY_TABLE;
 }
 
 /*
@@ -281,15 +273,13 @@ out_free_new_table:
  * This function can optionally re-use entries from an older integrity table.
  * To do this, specify old_blob_table_end and old_table.
  *
+ * On success, @wim->out_hdr.integrity_table_reshdr will be filled in with
+ * information about the integrity table that was written.
+ *
  * @wim:
  *     WIMStruct for the WIM file.  @wim->out_fd must be a seekable descriptor
  *     to the new WIM file, opened read-write, positioned at the location at
- *     which the integrity table is to be written.  Furthermore,
- *     @wim->hdr.integrity is expected to be a resource entry which will be set
- *     to the integrity table information on success.  In addition, if
- *     @old_blob_table_end != 0, @wim->hdr.integrity must initially contain
- *     information about the old integrity table, and @wim->in_fd must be a
- *     seekable descriptor to the original WIM file opened for reading.
+ *     which the integrity table is to be written.
  *
  * @new_blob_table_end:
  *     The offset of the byte directly following the blob table in the WIM
@@ -313,10 +303,6 @@ write_integrity_table(WIMStruct *wim,
        int ret;
        u32 new_table_size;
 
-       DEBUG("Writing integrity table "
-             "(new_blob_table_end=%"PRIu64", old_blob_table_end=%"PRIu64")",
-             new_blob_table_end, old_blob_table_end);
-
        wimlib_assert(old_blob_table_end <= new_blob_table_end);
 
        ret = calculate_integrity_table(&wim->out_fd, new_blob_table_end,
@@ -337,11 +323,10 @@ write_integrity_table(WIMStruct *wim,
                                             &wim->out_fd,
                                             WIMLIB_COMPRESSION_TYPE_NONE,
                                             0,
-                                            &wim->hdr.integrity_table_reshdr,
+                                            &wim->out_hdr.integrity_table_reshdr,
                                             NULL,
                                             0);
        FREE(new_table);
-       DEBUG("ret=%d", ret);
        return ret;
 }
 
@@ -444,10 +429,8 @@ check_wim_integrity(WIMStruct *wim)
        struct integrity_table *table;
        u64 end_blob_table_offset;
 
-       if (!wim_has_integrity_table(wim)) {
-               DEBUG("No integrity information.");
+       if (!wim_has_integrity_table(wim))
                return WIM_INTEGRITY_NONEXISTENT;
-       }
 
        end_blob_table_offset = wim->hdr.blob_table_reshdr.offset_in_wim +
                                wim->hdr.blob_table_reshdr.size_in_wim;