/* Creates and appends a 'struct wim_image_metadata' for an empty image.
*
* The resulting image will be the last in the WIM, so its index will be
* the new value of wim->hdr.image_count. */
static int
add_empty_image_metadata(WIMStruct *wim)
{
int ret;
struct wim_lookup_table_entry *metadata_lte;
struct wim_security_data *sd;
struct wim_image_metadata *imd;
/* Create lookup table entry for this metadata resource (for now really
* just a dummy entry). */
ret = WIMLIB_ERR_NOMEM;
metadata_lte = new_lookup_table_entry();
if (!metadata_lte)
goto out;
metadata_lte->flags = WIM_RESHDR_FLAG_METADATA;
metadata_lte->unhashed = 1;
/* Create empty security data (no security descriptors). */
sd = new_wim_security_data();
if (!sd)
goto out_free_metadata_lte;
imd = new_image_metadata();
if (!imd)
goto out_free_security_data;
/* A NULL root_dentry indicates a completely empty image, without even a
* root directory. */
imd->root_dentry = NULL;
imd->metadata_lte = metadata_lte;
imd->security_data = sd;
imd->modified = 1;
/* Append as next image index. */
ret = append_image_metadata(wim, imd);
if (ret)
put_image_metadata(imd, NULL);
goto out;
out_free_security_data:
free_wim_security_data(sd);
out_free_metadata_lte:
free_lookup_table_entry(metadata_lte);
out:
return ret;
}
/*
* Reads the security data from the metadata resource of a WIM image.
*
* @buf
* Buffer containing an uncompressed WIM metadata resource.
* @buf_len
* Length of the uncompressed metadata resource, in bytes.
* @sd_ret
* On success, a pointer to the resulting security data structure will be
* returned here.
*
* Note: There is no `offset' argument because the security data is located at
* the beginning of the metadata resource.
*
* Return values:
* WIMLIB_ERR_SUCCESS (0)
* WIMLIB_ERR_INVALID_METADATA_RESOURCE
* WIMLIB_ERR_NOMEM
*/
int
read_wim_security_data(const u8 *buf, size_t buf_len,
struct wim_security_data **sd_ret)
{
struct wim_security_data *sd;
int ret;
u64 total_len;
u64 sizes_size;
u64 size_no_descriptors;
const struct wim_security_data_disk *sd_disk;
const u8 *p;
if (buf_len < 8)
return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
sd = new_wim_security_data();
if (!sd)
goto out_of_memory;
sd_disk = (const struct wim_security_data_disk *)buf;
sd->total_length = le32_to_cpu(sd_disk->total_length);
sd->num_entries = le32_to_cpu(sd_disk->num_entries);
DEBUG("Reading security data: num_entries=%u, total_length=%u",
sd->num_entries, sd->total_length);
/* Length field of 0 is a special case that really means length
* of 8. */
if (sd->total_length == 0)
sd->total_length = 8;
/* 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)
goto out_invalid_sd;
/* Verify the listed total length of the security data is big enough to
* include the sizes array, verify that the file data is big enough to
* include it as well, then allocate the array of sizes.
*
* Note: The total length of the security data must fit in a 32-bit
* integer, even though each security descriptor size is a 64-bit
* integer. This is stupid, and we need to be careful not to actually
* let the security descriptor sizes be over 0xffffffff. */
if (sd->total_length > buf_len)
goto out_invalid_sd;
sizes_size = (u64)sd->num_entries * sizeof(u64);
size_no_descriptors = 8 + sizes_size;
if (size_no_descriptors > sd->total_length)
goto out_invalid_sd;
total_len = size_no_descriptors;
/* Return immediately if no security descriptors. */
if (sd->num_entries == 0)
goto out_align_total_length;
/* Allocate a new buffer for the sizes array */
sd->sizes = MALLOC(sizes_size);
if (!sd->sizes)
goto out_of_memory;
/* Copy the sizes array into the new buffer */
for (u32 i = 0; i < sd->num_entries; i++) {
sd->sizes[i] = le64_to_cpu(sd_disk->sizes[i]);
if (sd->sizes[i] > 0xffffffff)
goto out_invalid_sd;
}
p = (const u8*)sd_disk + size_no_descriptors;
/* Allocate the array of pointers to the security descriptors, then read
* them into separate buffers. */
sd->descriptors = CALLOC(sd->num_entries, sizeof(sd->descriptors[0]));
if (!sd->descriptors)
goto out_of_memory;
for (u32 i = 0; i < sd->num_entries; i++) {
if (sd->sizes[i] == 0)
continue;
total_len += sd->sizes[i];
if (total_len > (u64)sd->total_length)
goto out_invalid_sd;
sd->descriptors[i] = memdup(p, sd->sizes[i]);
if (!sd->descriptors[i])
goto out_of_memory;
p += sd->sizes[i];
}
out_align_total_length:
total_len = (total_len + 7) & ~7;
sd->total_length = (sd->total_length + 7) & ~7;
if (total_len != sd->total_length) {
WARNING("Expected WIM security data total length of "
"%u bytes, but calculated %u bytes",
sd->total_length, (unsigned)total_len);
}
*sd_ret = sd;
ret = 0;
goto out;
out_invalid_sd:
ERROR("WIM security data is invalid!");
ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
goto out_free_sd;
out_of_memory:
ERROR("Out of memory while reading WIM security data!");
ret = WIMLIB_ERR_NOMEM;
out_free_sd:
free_wim_security_data(sd);
out:
return ret;
}
