p = get_bytes(p, short_name_len, short_name);
if (*(u16*)p)
- WARNING("Expected two zero bytes following the file name "
+ WARNING("Expected two zero bytes following the short name of "
"`%s', but found non-zero bytes", file_name_utf8);
p += 2;
}
* included in the dentry->length field for some reason.
*/
if (inode->num_ads != 0) {
- if (calculated_size > metadata_resource_len - offset) {
- ERROR("Not enough space in metadata resource for "
- "alternate stream entries");
- ret = WIMLIB_ERR_INVALID_DENTRY;
- goto out_free_short_name;
+
+ /* Trying different lengths is just a hack to make sure we have
+ * a chance of reading the ADS entries correctly despite the
+ * poor documentation. */
+
+ if (calculated_size != dentry->length) {
+ WARNING("Trying calculated dentry length (%"PRIu64") "
+ "instead of dentry->length field (%"PRIu64") "
+ "to read ADS entries",
+ calculated_size, dentry->length);
}
- ret = read_ads_entries(&metadata_resource[offset + calculated_size],
- inode,
- metadata_resource_len - offset - calculated_size);
- if (ret != 0)
- goto out_free_short_name;
+ u64 lengths_to_try[3] = {calculated_size,
+ dentry->length + 7 & ~7,
+ dentry->length};
+ ret = WIMLIB_ERR_INVALID_DENTRY;
+ for (size_t i = 0; i < ARRAY_LEN(lengths_to_try); i++) {
+ if (lengths_to_try[i] > metadata_resource_len - offset)
+ continue;
+ ret = read_ads_entries(&metadata_resource[offset + lengths_to_try[i]],
+ inode,
+ metadata_resource_len - offset - lengths_to_try[i]);
+ if (ret == 0)
+ goto out;
+ }
+ ERROR("Failed to read alternate data stream "
+ "entries of `%s'", dentry->file_name_utf8);
+ goto out_free_short_name;
}
+out:
/* We've read all the data for this dentry. Set the names and their
* lengths, and we've done. */
return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
}
+ if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) {
+ ERROR("Metadata resource is too large (%"PRIu64" bytes",
+ metadata_len);
+ return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
+ }
+
/* Allocate memory for the uncompressed metadata resource. */
buf = MALLOC(metadata_len);
* and if successful, go ahead and calculate the offset in the metadata
* resource of the root dentry. */
+ wimlib_assert(imd->security_data == NULL);
ret = read_security_data(buf, metadata_len, &imd->security_data);
if (ret != 0)
goto out_free_buf;
- get_u32(buf, &dentry_offset);
- if (dentry_offset == 0)
- dentry_offset = 8;
- dentry_offset = (dentry_offset + 7) & ~7;
+ dentry_offset = imd->security_data->total_length + 7 & ~7;
+
+ if (dentry_offset == 0) {
+ ERROR("Integer overflow while reading metadata resource");
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
+ goto out_free_security_data;
+ }
/* Allocate memory for the root dentry and read it into memory */
dentry = MALLOC(sizeof(struct dentry));
* invalid. However, a security descriptor like this exists in the Windows 7
* install.wim. Here, security descriptors matching this pattern are modified
* to have no SACL. This should make no difference since the SACL had no
- * entries anyway; however his ensures that that the security descriptors pass
+ * entries anyway; however this ensures that that the security descriptors pass
* the validation in libntfs-3g.
*/
static void empty_sacl_fixup(char *descr, u64 *size_p)
int ret;
u64 total_len;
+ /*
+ * Sorry this function is excessively complicated--- I'm just being
+ * extremely careful about integer overflows.
+ */
+
sd = MALLOC(sizeof(struct wim_security_data));
if (!sd) {
ERROR("Out of memory");
p = get_u32(p, &sd->total_length);
p = get_u32(p, (u32*)&sd->num_entries);
- if (sd->num_entries > 0x7fffffff) {
+ /* The security_id field of each dentry is a signed 32-bit integer, so
+ * the possible indices into the security descriptors table are 0
+ * through 0x7fffffff. Which means 0x80000000 security descriptors
+ * maximum. Not like you should ever have anywhere close to that many
+ * security descriptors! */
+ if (sd->num_entries > 0x80000000) {
ERROR("Security data has too many entries!");
- ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
- goto out_free_sd;
+ goto out_invalid_sd;
}
/* Verify the listed total length of the security data is big enough to
ERROR("Security data total length (%u) is bigger than the "
"metadata resource length (%"PRIu64")",
sd->total_length, metadata_resource_len);
- ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
- goto out_free_sd;
+ goto out_invalid_sd;
}
DEBUG("Reading security data: %u entries, length = %u",
sd->num_entries, sd->total_length);
if (sd->num_entries == 0) {
- /* No security data. */
- total_len = 8;
- goto out;
+ /* No security descriptors. */
+ if (sd->total_length != 0 && sd->total_length != 8) {
+ ERROR("Invalid security data length (%u): expected 0 or 8",
+ sd->total_length);
+ goto out_invalid_sd;
+ }
+ sd->total_length = 8;
+ goto out_return_sd;
}
u64 sizes_size = (u64)sd->num_entries * sizeof(u64);
ERROR("Security data total length of %u is too short because "
"there must be at least %"PRIu64" bytes of security data",
sd->total_length, 8 + sizes_size);
- ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
- goto out_free_sd;
+ goto out_invalid_sd;
+ }
+ if (sizeof(size_t) < 8 && sizes_size > 0xffffffff) {
+ ERROR("Too many security descriptors!");
+ goto out_invalid_sd;
}
sd->sizes = MALLOC(sizes_size);
if (!sd->sizes) {
"(current total length = %"PRIu64", security "
"descriptor size = %"PRIu64")",
total_len, sd->sizes[i]);
- ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
- goto out_free_sd;
+ goto out_invalid_sd;
}
total_len += sd->sizes[i];
+ /* This check assures that the descriptor size fits in a 32 bit
+ * integer. Because if it didn't, the total length would come
+ * out bigger than sd->total_length, which is a 32 bit integer.
+ * */
if (total_len > (u64)sd->total_length) {
ERROR("Security data total length of %u is too short "
"because there are at least %"PRIu64" bytes of "
"security data", sd->total_length, total_len);
- ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
- goto out_free_sd;
+ goto out_invalid_sd;
}
sd->descriptors[i] = MALLOC(sd->sizes[i]);
if (!sd->descriptors[i]) {
p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]);
}
-out:
- sd->total_length = (u32)total_len;
+ wimlib_assert(total_len <= 0xffffffff);
+ if ((total_len + 7 & ~7) != ((sd->total_length + 7) & ~7)) {
+ ERROR("Expected security data total length = %u, but "
+ "calculated %u", sd->total_length, total_len);
+ goto out_invalid_sd;
+ }
+ sd->total_length = total_len;
+out_return_sd:
*sd_p = sd;
return 0;
+out_invalid_sd:
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
out_free_sd:
free_security_data(sd);
return ret;