/*
* security.c
*
- * Read and write the WIM security data. The security data is a table of
- * security descriptors. Each WIM image has its own security data, but it's
- * possible that an image's security data have no security descriptors.
+ * Read and write the per-WIM-image table of security descriptors.
*/
/*
*/
#include "wimlib_internal.h"
-#include "io.h"
+#include "buffer_io.h"
#include "security.h"
-/*
+/*
* This is a hack to work around a problem in libntfs-3g. libntfs-3g validates
* security descriptors with a function named ntfs_valid_descr().
* ntfs_valid_descr() considers a security descriptor that ends in a SACL
* 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)
+static void empty_sacl_fixup(u8 *descr, u64 *size_p)
{
if (*size_p >= sizeof(SecurityDescriptor)) {
SecurityDescriptor *sd = (SecurityDescriptor*)descr;
}
}
-/*
+/*
* Reads the security data from the metadata resource.
*
* @metadata_resource: An array that contains the uncompressed metadata
* resource for the WIM file.
- * @metadata_resource_len: The length of @metadata_resource. It MUST be at
+ * @metadata_resource_len: The length of @metadata_resource. It must be at
* least 8 bytes.
* @sd_p: A pointer to a pointer to a wim_security_data structure that
* will be filled in with a pointer to a new wim_security_data
int ret;
u64 total_len;
+ wimlib_assert(metadata_resource_len >= 8);
+
+ /*
+ * 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. We allow the total_length field to
+ * be either 8 (which is correct, since there are always 2
+ * 32-bit integers) or 0. */
+ 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);
u64 size_no_descriptors = 8 + sizes_size;
if (size_no_descriptors > (u64)sd->total_length) {
ERROR("Security data total length of %u is too short because "
- "there must be at least %"PRIu64" bytes of security data",
+ "there seem to 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;
}
+
sd->sizes = MALLOC(sizes_size);
if (!sd->sizes) {
ret = WIMLIB_ERR_NOMEM;
"(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 ensures 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;
+ "because there seem to be at least %"PRIu64" "
+ "bytes of security data",
+ sd->total_length, total_len);
+ 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, (unsigned)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;
}
-/*
+/*
* Writes security data to an in-memory buffer.
*/
u8 *write_security_data(const struct wim_security_data *sd, u8 *p)
printf(" ACE Count = %u\n", ace_count);
p += sizeof(ACL);
- for (uint i = 0; i < acl->ace_count; i++) {
+ for (u16 i = 0; i < ace_count; i++) {
const ACEHeader *hdr = (const ACEHeader*)p;
printf(" [ACE]\n");
printf(" ACE type = %d\n", hdr->type);
print_byte_field(sid->identifier_authority,
sizeof(sid->identifier_authority));
putchar('\n');
- for (uint i = 0; i < sid->sub_authority_count; i++)
+ for (u8 i = 0; i < sid->sub_authority_count; i++)
printf(" Subauthority %u = %u\n",
i, le32_to_cpu(sid->sub_authority[i]));
putchar('\n');
print_acl(p + dacl_offset, "Discretionary");
}
-/*
+/*
* Prints the security data for a WIM file.
*/
void print_security_data(const struct wim_security_data *sd)
{
+ wimlib_assert(sd != NULL);
+
puts("[SECURITY DATA]");
printf("Length = %"PRIu32" bytes\n", sd->total_length);
printf("Number of Entries = %"PRIu32"\n", sd->num_entries);
for (u32 i = 0; i < sd->num_entries; i++) {
- printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n",
+ printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n",
i, sd->sizes[i]);
print_security_descriptor(sd->descriptors[i], sd->sizes[i]);
putchar('\n');
void free_security_data(struct wim_security_data *sd)
{
- if (!sd)
- return;
- wimlib_assert(sd->refcnt != 0);
- if (--sd->refcnt == 0) {
- u8 **descriptors = sd->descriptors;
- u32 num_entries = sd->num_entries;
- if (descriptors)
- while (num_entries--)
- FREE(*descriptors++);
- FREE(sd->sizes);
- FREE(sd->descriptors);
- FREE(sd);
+ if (sd) {
+ wimlib_assert(sd->refcnt != 0);
+ if (--sd->refcnt == 0) {
+ u8 **descriptors = sd->descriptors;
+ u32 num_entries = sd->num_entries;
+ if (descriptors)
+ while (num_entries--)
+ FREE(*descriptors++);
+ FREE(sd->sizes);
+ FREE(sd->descriptors);
+ FREE(sd);
+ }
}
}
git://wimlib.net / wimlib / blobdiff