/*
* 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 per-WIM-image table of security descriptors.
*/
/*
* This file is part of wimlib, a library for working with WIM files.
*
* wimlib 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)
+ * 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.
*
* 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 Lesser General Public License for more
+ * 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
+ * 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 "buffer_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 this ensures that that the security descriptors pass
+ * the validation in libntfs-3g.
+ */
+static void empty_sacl_fixup(u8 *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 = cpu_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. 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 = metadata_resource;
p = get_u32(p, &sd->total_length);
- p = get_u32(p, &sd->num_entries);
+ p = get_u32(p, (u32*)&sd->num_entries);
+
+ /* 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!");
+ 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
ERROR("Security data total length (%u) is bigger than the "
"metadata resource length (%"PRIu64")",
sd->total_length, metadata_resource_len);
- ret = WIMLIB_ERR_INVALID_RESOURCE_SIZE;
- 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_RESOURCE_SIZE;
- goto out_free_sd;
+ goto out_invalid_sd;
}
+
sd->sizes = MALLOC(sizes_size);
if (!sd->sizes) {
ret = WIMLIB_ERR_NOMEM;
/* Copy the sizes array in from the file data. */
p = get_bytes(p, sizes_size, sd->sizes);
- array_to_le64(sd->sizes, sd->num_entries);
+ array_le64_to_cpu(sd->sizes, sd->num_entries);
/* Allocate the array of pointers to descriptors, and read them in. */
sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*));
"(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_RESOURCE_SIZE;
- 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]) {
goto out_free_sd;
}
p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
+ empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]);
+ }
+ 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;
}
-out:
- sd->total_length = (u32)total_len;
+ 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)
DEBUG("Writing security data (total_length = %"PRIu32", num_entries "
"= %"PRIu32")", sd->total_length, sd->num_entries);
+ u32 aligned_length = (sd->total_length + 7) & ~7;
+
u8 *orig_p = p;
- p = put_u32(p, sd->total_length);
+ p = put_u32(p, aligned_length);
p = put_u32(p, sd->num_entries);
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);
DEBUG("Successfully wrote security data.");
return p;
}
-/* 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... */
-
-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 = le16_to_cpu(acl->acl_size);
+ u16 ace_count = le16_to_cpu(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;
+ for (u16 i = 0; i < ace_count; i++) {
+ 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;
- printf(" ACE mask = %x\n", to_le32(aaa->mask));
- printf(" SID start = %u\n", to_le32(aaa->sid_start));
+ const AccessAllowedACE *aaa = (const AccessAllowedACE*)hdr;
+ printf(" ACE mask = %x\n", le32_to_cpu(aaa->mask));
+ printf(" SID start = %u\n", le32_to_cpu(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 = ");
- print_byte_field(sid->identifier_authority, sizeof(sid->identifier_authority));
+ print_byte_field(sid->identifier_authority,
+ sizeof(sid->identifier_authority));
+ putchar('\n');
+ 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');
- for (uint i = 0; i < sid->sub_authority_count; i++)
- printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i]));
}
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 = le16_to_cpu(sd->security_descriptor_control);
+ u32 owner_offset = le32_to_cpu(sd->owner_offset);
+ u32 group_offset = le32_to_cpu(sd->group_offset);
+ u32 sacl_offset = le32_to_cpu(sd->sacl_offset);
+ u32 dacl_offset = le32_to_cpu(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");
}
-/*
+/*
* 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 >= 1);
- if (sd->refcnt == 1) {
- 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);
- } else {
- sd->refcnt--;
+ 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);
+ }
}
}
-
-#endif
git://wimlib.net / wimlib / blobdiff