/*
* security.c
*
- * Read the security data from the WIM. Doing anything with the security data
- * is not yet implemented other than printing some information about it.
- *
+ * 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.
+ */
+
+/*
* Copyright (C) 2012 Eric Biggers
*
- * wimlib - Library for working with WIM files
+ * This file is part of wimlib, a library for working with WIM files.
*
- * This library 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
- * Software Foundation; either version 2.1 of the License, or (at your option) any
- * later version.
+ * wimlib is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option)
+ * any later version.
*
- * This library is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
- * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
*
- * You should have received a copy of the GNU Lesser General Public License along
- * with this library; if not, write to the Free Software Foundation, Inc., 59
- * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the GNU General Public License
+ * along with wimlib; if not, see http://www.gnu.org/licenses/.
*/
#include "wimlib_internal.h"
#include "io.h"
#include "security.h"
-#ifdef ENABLE_SECURITY_DATA
+/*
+ * 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
+ * (Sysetm Access Control List) with no ACE's (Access Control Entries) to be
+ * 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
+ * the validation in libntfs-3g.
+ */
+static void empty_sacl_fixup(char *descr, u64 *size_p)
+{
+ if (*size_p >= sizeof(SecurityDescriptor)) {
+ SecurityDescriptor *sd = (SecurityDescriptor*)descr;
+ u32 sacl_offset = le32_to_cpu(sd->sacl_offset);
+ if (sacl_offset == *size_p - sizeof(ACL)) {
+ sd->sacl_offset = to_le32(0);
+ *size_p -= sizeof(ACL);
+ }
+ }
+}
/*
* 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.
- * @sd_p: A pointer to a pointer wim_security_data structure that will be filled
- * in with a pointer to a new wim_security_data structure on success.
+ * @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
+ * structure on success.
*
* Note: There is no `offset' argument because the security data is located at
* the beginning of the metadata resource.
*/
-int read_security_data(const u8 metadata_resource[],
- u64 metadata_resource_len, struct wim_security_data **sd_p)
+int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len,
+ struct wim_security_data **sd_p)
{
struct wim_security_data *sd;
const u8 *p;
- u64 sizes_size;
+ int ret;
+ u64 total_len;
- if (metadata_resource_len < 8) {
- ERROR("Not enough space in %"PRIu64"-byte file resource for "
- "security data!\n", metadata_resource_len);
- return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
- }
sd = MALLOC(sizeof(struct wim_security_data));
- if (!sd)
+ if (!sd) {
+ ERROR("Out of memory");
return WIMLIB_ERR_NOMEM;
- p = get_u32(metadata_resource, &sd->total_length);
- p = get_u32(p, &sd->num_entries);
+ }
+ sd->sizes = NULL;
+ sd->descriptors = NULL;
+ sd->refcnt = 1;
+
+ p = metadata_resource;
+ p = get_u32(p, &sd->total_length);
+ p = get_u32(p, (u32*)&sd->num_entries);
+
+ if (sd->num_entries > 0x7fffffff) {
+ ERROR("Security data has too many entries!");
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
+ goto out_free_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. */
- sizes_size = sd->num_entries * sizeof(u64);
+ * 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 ((u64)sd->total_length > metadata_resource_len) {
+ 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;
+ }
- DEBUG("Reading security data with %u entries\n", sd->num_entries);
+ DEBUG("Reading security data: %u entries, length = %u",
+ sd->num_entries, sd->total_length);
if (sd->num_entries == 0) {
- FREE(sd);
- return 0;
+ /* No security data. */
+ total_len = 8;
+ goto out;
}
+ u64 sizes_size = (u64)sd->num_entries * sizeof(u64);
u64 size_no_descriptors = 8 + sizes_size;
- if (size_no_descriptors > sd->total_length) {
- ERROR("Security data total length of %"PRIu64" is too short because\n"
- "there must be at least %"PRIu64" bytes of security "
- "data!\n", sd->total_length,
- 8 + sizes_size);
- FREE(sd);
- return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
- }
- if (size_no_descriptors > metadata_resource_len) {
- ERROR("File resource of %"PRIu64" bytes is not big enough\n"
- "to hold security data of at least %"PRIu64" "
- "bytes!\n", metadata_resource_len, size_no_descriptors);
- FREE(sd);
- return WIMLIB_ERR_INVALID_RESOURCE_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",
+ sd->total_length, 8 + sizes_size);
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
+ goto out_free_sd;
}
sd->sizes = MALLOC(sizes_size);
if (!sd->sizes) {
- FREE(sd);
- return WIMLIB_ERR_NOMEM;
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_sd;
}
/* Copy the sizes array in from the file data. */
/* Allocate the array of pointers to descriptors, and read them in. */
sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*));
if (!sd->descriptors) {
- FREE(sd);
- FREE(sd->sizes);
- return WIMLIB_ERR_NOMEM;
+ ERROR("Out of memory while allocating security "
+ "descriptors");
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_sd;
}
- u64 total_len = size_no_descriptors;
+ total_len = size_no_descriptors;
- for (uint i = 0; i < sd->num_entries; i++) {
- total_len += sd->sizes[i];
- if (total_len > sd->total_length) {
- ERROR("Security data total length of %"PRIu64" is too "
- "short because there are at least %"PRIu64" "
- "bytes of security data!\n",
- sd->total_length, total_len);
- free_security_data(sd);
- return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
+ for (u32 i = 0; i < sd->num_entries; i++) {
+ /* Watch out for huge security descriptor sizes that could
+ * overflow the total length and wrap it around. */
+ if (total_len + sd->sizes[i] < total_len) {
+ ERROR("Caught overflow in security descriptor lengths "
+ "(current total length = %"PRIu64", security "
+ "descriptor size = %"PRIu64")",
+ total_len, sd->sizes[i]);
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
+ goto out_free_sd;
}
- if (total_len > metadata_resource_len) {
- ERROR("File resource of %"PRIu64" bytes is not big enough "
- "to hold security data of at least %"PRIu64" "
- "bytes!\n", metadata_resource_len, total_len);
- free_security_data(sd);
- return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
+ total_len += sd->sizes[i];
+ 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;
}
sd->descriptors[i] = MALLOC(sd->sizes[i]);
if (!sd->descriptors[i]) {
- free_security_data(sd);
- return WIMLIB_ERR_NOMEM;
+ ERROR("Out of memory while allocating security "
+ "descriptors");
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_sd;
}
p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
+ empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]);
}
- sd->refcnt = 1;
+out:
+ sd->total_length = (u32)total_len;
*sd_p = sd;
return 0;
+out_free_sd:
+ free_security_data(sd);
+ return ret;
}
/*
*/
u8 *write_security_data(const struct wim_security_data *sd, u8 *p)
{
- if (sd) {
- DEBUG("Writing security data (total_length = %u, "
- "num_entries = %u)\n", sd->total_length,
- sd->num_entries);
- u8 *orig_p = p;
- p = put_u32(p, sd->total_length);
- p = put_u32(p, sd->num_entries);
+ DEBUG("Writing security data (total_length = %"PRIu32", num_entries "
+ "= %"PRIu32")", sd->total_length, sd->num_entries);
- for (uint i = 0; i < sd->num_entries; i++)
- p = put_u64(p, sd->sizes[i]);
+ u32 aligned_length = (sd->total_length + 7) & ~7;
- for (uint i = 0; i < sd->num_entries; i++)
- p = put_bytes(p, sd->sizes[i], sd->descriptors[i]);
+ u8 *orig_p = p;
+ p = put_u32(p, aligned_length);
+ p = put_u32(p, sd->num_entries);
- wimlib_assert(p - orig_p <= sd->total_length);
+ for (u32 i = 0; i < sd->num_entries; i++)
+ p = put_u64(p, sd->sizes[i]);
- DEBUG("Successfully wrote security data.\n");
- return orig_p + sd->total_length;
- } else {
- DEBUG("Writing security data (total_length = 8, "
- "num_entries = 0)\n");
- p = put_u32(p, 8);
- return put_u32(p, 0);
+ for (u32 i = 0; i < sd->num_entries; i++)
+ p = put_bytes(p, sd->sizes[i], sd->descriptors[i]);
- }
-}
+ wimlib_assert(p - orig_p == sd->total_length);
+ p = put_zeroes(p, aligned_length - sd->total_length);
-/* XXX We don't actually do anything with the ACL's yet besides being able to
- * print a few things. It seems it would be a lot of work to have comprehensive
- * support for all the weird flags and stuff, and Windows PE seems to be okay
- * running from a WIM file that doesn't have any security data at all... */
+ DEBUG("Successfully wrote security data.");
+ return p;
+}
-static void print_acl(const u8 *p)
+static void print_acl(const u8 *p, const char *type)
{
- ACL *acl = (ACL*)p;
- TO_LE16(acl->acl_size);
- TO_LE16(acl->acl_count);
- printf(" [ACL]\n");
- printf(" Revision = %u\n", acl->revision);
- printf(" ACL Size = %u\n", acl->acl_size);
- printf(" ACE Count = %u\n", acl->ace_count);
+ const ACL *acl = (const ACL*)p;
+ u8 revision = acl->revision;
+ u16 acl_size = to_le16(acl->acl_size);
+ u16 ace_count = to_le16(acl->ace_count);
+ printf(" [%s ACL]\n", type);
+ printf(" Revision = %u\n", revision);
+ printf(" ACL Size = %u\n", acl_size);
+ printf(" ACE Count = %u\n", ace_count);
p += sizeof(ACL);
for (uint i = 0; i < acl->ace_count; i++) {
- ACEHeader *hdr = (ACEHeader*)p;
+ const ACEHeader *hdr = (const ACEHeader*)p;
printf(" [ACE]\n");
printf(" ACE type = %d\n", hdr->type);
printf(" ACE flags = 0x%x\n", hdr->flags);
printf(" ACE size = %u\n", hdr->size);
- AccessAllowedACE *aaa = (AccessAllowedACE*)hdr;
+ const AccessAllowedACE *aaa = (const AccessAllowedACE*)hdr;
printf(" ACE mask = %x\n", to_le32(aaa->mask));
printf(" SID start = %u\n", to_le32(aaa->sid_start));
p += hdr->size;
}
+ putchar('\n');
}
-static void print_sid(const u8 *p)
+static void print_sid(const u8 *p, const char *type)
{
- SID *sid = (SID*)p;
- printf(" [SID]\n");
+ const SID *sid = (const SID*)p;
+ printf(" [%s SID]\n", type);
printf(" Revision = %u\n", sid->revision);
printf(" Subauthority count = %u\n", sid->sub_authority_count);
printf(" Identifier authority = ");
putchar('\n');
for (uint i = 0; i < sid->sub_authority_count; i++)
printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i]));
+ putchar('\n');
}
static void print_security_descriptor(const u8 *p, u64 size)
{
- SecurityDescriptor *sd = (SecurityDescriptor*)p;
- TO_LE16(sd->security_descriptor_control);
- TO_LE32(sd->owner_offset);
- TO_LE32(sd->group_offset);
- TO_LE32(sd->sacl_offset);
- TO_LE32(sd->dacl_offset);
- printf("Revision = %u\n", sd->revision);
- printf("Security Descriptor Control = %u\n", sd->security_descriptor_control);
- printf("Owner offset = %u\n", sd->owner_offset);
- printf("Group offset = %u\n", sd->group_offset);
- printf("System ACL offset = %u\n", sd->sacl_offset);
- printf("Discretionary ACL offset = %u\n", sd->dacl_offset);
+ const SecurityDescriptor *sd = (const SecurityDescriptor*)p;
+ u8 revision = sd->revision;
+ u16 control = to_le16(sd->security_descriptor_control);
+ u32 owner_offset = to_le32(sd->owner_offset);
+ u32 group_offset = to_le32(sd->group_offset);
+ u32 sacl_offset = to_le32(sd->sacl_offset);
+ u32 dacl_offset = to_le32(sd->dacl_offset);
+ printf("Revision = %u\n", revision);
+ printf("Security Descriptor Control = %#x\n", control);
+ printf("Owner offset = %u\n", owner_offset);
+ printf("Group offset = %u\n", group_offset);
+ printf("System ACL offset = %u\n", sacl_offset);
+ printf("Discretionary ACL offset = %u\n", dacl_offset);
if (sd->owner_offset != 0)
- print_sid(p + sd->owner_offset);
+ print_sid(p + owner_offset, "Owner");
if (sd->group_offset != 0)
- print_sid(p + sd->group_offset);
+ print_sid(p + group_offset, "Group");
if (sd->sacl_offset != 0)
- print_acl(p + sd->sacl_offset);
+ print_acl(p + sacl_offset, "System");
if (sd->dacl_offset != 0)
- print_acl(p + sd->dacl_offset);
+ print_acl(p + dacl_offset, "Discretionary");
}
/*
void print_security_data(const struct wim_security_data *sd)
{
puts("[SECURITY DATA]");
- if (sd) {
- printf("Length = %u bytes\n", sd->total_length);
- printf("Number of Entries = %u\n", sd->num_entries);
+ printf("Length = %"PRIu32" bytes\n", sd->total_length);
+ printf("Number of Entries = %"PRIu32"\n", sd->num_entries);
- u64 num_entries = (u64)sd->num_entries;
- for (u64 i = 0; i < num_entries; i++) {
- printf("[SecurityDescriptor %"PRIu64", "
- "length = %"PRIu64"]\n",
- i, sd->sizes[i]);
- print_security_descriptor(sd->descriptors[i],
- sd->sizes[i]);
- putchar('\n');
- }
- } else {
- puts("Length = 8 bytes\n"
- "Number of Entries = 0");
+ for (u32 i = 0; i < sd->num_entries; i++) {
+ printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n",
+ i, sd->sizes[i]);
+ print_security_descriptor(sd->descriptors[i], sd->sizes[i]);
+ putchar('\n');
}
putchar('\n');
}
{
if (!sd)
return;
- wimlib_assert(sd->refcnt >= 1);
- if (sd->refcnt == 1) {
+ wimlib_assert(sd->refcnt != 0);
+ if (--sd->refcnt == 0) {
u8 **descriptors = sd->descriptors;
- u32 num_entries = sd->num_entries;
-
+ u32 num_entries = sd->num_entries;
if (descriptors)
while (num_entries--)
FREE(*descriptors++);
FREE(sd->sizes);
FREE(sd->descriptors);
FREE(sd);
- } else {
- sd->refcnt--;
}
}
-
-#endif
git://wimlib.net / wimlib / blobdiff