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   1 /*
   2  * security.c
   3  *
   4  * Read the security data from the WIM.  Doing anything with the security data
   5  * is not yet implemented other than printing some information about it.
   6  */
   7
   8 /*
   9  * Copyright (C) 2012 Eric Biggers
  10  *
  11  * This file is part of wimlib, a library for working with WIM files.
  12  *
  13  * wimlib is free software; you can redistribute it and/or modify it under the
  14  * terms of the GNU Lesser General Public License as published by the Free
  15  * Software Foundation; either version 2.1 of the License, or (at your option)
  16  * any later version.
  17  *
  18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  20  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU Lesser General Public License
  24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  25  */
  26
  27 #include "wimlib_internal.h"
  28 #include "io.h"
  29 #include "security.h"
  30
  31 /*
  32  * Reads the security data from the metadata resource.
  33  *
  34  * @metadata_resource:  An array that contains the uncompressed metadata
  35  *                              resource for the WIM file.
  36  * @metadata_resource_len:      The length of @metadata_resource.  It MUST be at
  37  *                              least 8 bytes.
  38  * @sd_p:       A pointer to a pointer to a wim_security_data structure that
  39  *              will be filled in with a pointer to a new wim_security_data
  40  *              structure on success.
  41  *
  42  * Note: There is no `offset' argument because the security data is located at
  43  * the beginning of the metadata resource.
  44  */
  45 int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len,
  46                        struct wim_security_data **sd_p)
  47 {
  48         struct wim_security_data *sd;
  49         const u8 *p;
  50         int ret;
  51         u64 total_len;
  52
  53         sd = MALLOC(sizeof(struct wim_security_data));
  54         if (!sd) {
  55                 ERROR("Out of memory");
  56                 return WIMLIB_ERR_NOMEM;
  57         }
  58         sd->sizes       = NULL;
  59         sd->descriptors = NULL;
  60         sd->refcnt      = 1;
  61
  62         p = metadata_resource;
  63         p = get_u32(p, &sd->total_length);
  64         p = get_u32(p, &sd->num_entries);
  65
  66         /* Verify the listed total length of the security data is big enough to
  67          * include the sizes array, verify that the file data is big enough to
  68          * include it as well, then allocate the array of sizes.
  69          *
  70          * Note: The total length of the security data must fit in a 32-bit
  71          * integer, even though each security descriptor size is a 64-bit
  72          * integer.  This is stupid, and we need to be careful not to actually
  73          * let the security descriptor sizes be over 0xffffffff.  */
  74         if ((u64)sd->total_length > metadata_resource_len) {
  75                 ERROR("Security data total length (%u) is bigger than the "
  76                       "metadata resource length (%"PRIu64")",
  77                       sd->total_length, metadata_resource_len);
  78                 ret = WIMLIB_ERR_INVALID_RESOURCE_SIZE;
  79                 goto out_free_sd;
  80         }
  81
  82         DEBUG("Reading security data: %u entries, length = %u",
  83               sd->num_entries, sd->total_length);
  84
  85         if (sd->num_entries == 0) {
  86                 /* No security data. */
  87                 total_len = 8;
  88                 goto out;
  89         }
  90
  91         u64 sizes_size = (u64)sd->num_entries * sizeof(u64);
  92         u64 size_no_descriptors = 8 + sizes_size;
  93         if (size_no_descriptors > (u64)sd->total_length) {
  94                 ERROR("Security data total length of %u is too short because "
  95                       "there must be at least %"PRIu64" bytes of security data",
  96                       sd->total_length, 8 + sizes_size);
  97                 ret = WIMLIB_ERR_INVALID_RESOURCE_SIZE;
  98                 goto out_free_sd;
  99         }
 100         sd->sizes = MALLOC(sizes_size);
 101         if (!sd->sizes) {
 102                 ret = WIMLIB_ERR_NOMEM;
 103                 goto out_free_sd;
 104         }
 105
 106         /* Copy the sizes array in from the file data. */
 107         p = get_bytes(p, sizes_size, sd->sizes);
 108         array_to_le64(sd->sizes, sd->num_entries);
 109
 110         /* Allocate the array of pointers to descriptors, and read them in. */
 111         sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*));
 112         if (!sd->descriptors) {
 113                 ERROR("Out of memory while allocating security "
 114                       "descriptors");
 115                 ret = WIMLIB_ERR_NOMEM;
 116                 goto out_free_sd;
 117         }
 118         total_len = size_no_descriptors;
 119
 120         for (u32 i = 0; i < sd->num_entries; i++) {
 121                 /* Watch out for huge security descriptor sizes that could
 122                  * overflow the total length and wrap it around. */
 123                 if (total_len + sd->sizes[i] < total_len) {
 124                         ERROR("Caught overflow in security descriptor lengths "
 125                               "(current total length = %"PRIu64", security "
 126                               "descriptor size = %"PRIu64")",
 127                               total_len, sd->sizes[i]);
 128                         ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
 129                         goto out_free_sd;
 130                 }
 131                 total_len += sd->sizes[i];
 132                 if (total_len > (u64)sd->total_length) {
 133                         ERROR("Security data total length of %u is too short "
 134                               "because there are at least %"PRIu64" bytes of "
 135                               "security data", sd->total_length, total_len);
 136                         ret = WIMLIB_ERR_INVALID_RESOURCE_SIZE;
 137                         goto out_free_sd;
 138                 }
 139                 sd->descriptors[i] = MALLOC(sd->sizes[i]);
 140                 if (!sd->descriptors[i]) {
 141                         ERROR("Out of memory while allocating security "
 142                               "descriptors");
 143                         ret = WIMLIB_ERR_NOMEM;
 144                         goto out_free_sd;
 145                 }
 146                 p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
 147         }
 148 out:
 149         sd->total_length = (u32)total_len;
 150         *sd_p = sd;
 151         return 0;
 152 out_free_sd:
 153         free_security_data(sd);
 154         return ret;
 155 }
 156
 157 /*
 158  * Writes security data to an in-memory buffer.
 159  */
 160 u8 *write_security_data(const struct wim_security_data *sd, u8 *p)
 161 {
 162         DEBUG("Writing security data (total_length = %"PRIu32", num_entries "
 163               "= %"PRIu32")", sd->total_length, sd->num_entries);
 164
 165         u8 *orig_p = p;
 166         p = put_u32(p, sd->total_length);
 167         p = put_u32(p, sd->num_entries);
 168
 169         for (u32 i = 0; i < sd->num_entries; i++)
 170                 p = put_u64(p, sd->sizes[i]);
 171
 172         for (u32 i = 0; i < sd->num_entries; i++)
 173                 p = put_bytes(p, sd->sizes[i], sd->descriptors[i]);
 174
 175         wimlib_assert(p - orig_p == sd->total_length);
 176
 177         DEBUG("Successfully wrote security data.");
 178         return p;
 179 }
 180
 181 static void print_acl(const u8 *p, const char *type)
 182 {
 183         ACL *acl = (ACL*)p;
 184         TO_LE16(acl->acl_size);
 185         TO_LE16(acl->acl_count);
 186         printf("    [%s ACL]\n", type);
 187         printf("    Revision = %u\n", acl->revision);
 188         printf("    ACL Size = %u\n", acl->acl_size);
 189         printf("    ACE Count = %u\n", acl->ace_count);
 190
 191         p += sizeof(ACL);
 192         for (uint i = 0; i < acl->ace_count; i++) {
 193                 ACEHeader *hdr = (ACEHeader*)p;
 194                 printf("        [ACE]\n");
 195                 printf("        ACE type  = %d\n", hdr->type);
 196                 printf("        ACE flags = 0x%x\n", hdr->flags);
 197                 printf("        ACE size  = %u\n", hdr->size);
 198                 AccessAllowedACE *aaa = (AccessAllowedACE*)hdr;
 199                 printf("        ACE mask = %x\n", to_le32(aaa->mask));
 200                 printf("        SID start = %u\n", to_le32(aaa->sid_start));
 201                 p += hdr->size;
 202         }
 203         putchar('\n');
 204 }
 205
 206 static void print_sid(const u8 *p, const char *type)
 207 {
 208         SID *sid = (SID*)p;
 209         printf("    [%s SID]\n", type);
 210         printf("    Revision = %u\n", sid->revision);
 211         printf("    Subauthority count = %u\n", sid->sub_authority_count);
 212         printf("    Identifier authority = ");
 213         print_byte_field(sid->identifier_authority, sizeof(sid->identifier_authority));
 214         putchar('\n');
 215         for (uint i = 0; i < sid->sub_authority_count; i++)
 216                 printf("    Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i]));
 217         putchar('\n');
 218 }
 219
 220 static void print_security_descriptor(const u8 *p, u64 size)
 221 {
 222         SecurityDescriptor *sd = (SecurityDescriptor*)p;
 223         TO_LE16(sd->security_descriptor_control);
 224         TO_LE32(sd->owner_offset);
 225         TO_LE32(sd->group_offset);
 226         TO_LE32(sd->sacl_offset);
 227         TO_LE32(sd->dacl_offset);
 228         printf("Revision = %u\n", sd->revision);
 229         printf("Security Descriptor Control = %#x\n", sd->security_descriptor_control);
 230         printf("Owner offset = %u\n", sd->owner_offset);
 231         printf("Group offset = %u\n", sd->group_offset);
 232         printf("System ACL offset = %u\n", sd->sacl_offset);
 233         printf("Discretionary ACL offset = %u\n", sd->dacl_offset);
 234
 235         if (sd->owner_offset != 0)
 236                 print_sid(p + sd->owner_offset, "Owner");
 237         if (sd->group_offset != 0)
 238                 print_sid(p + sd->group_offset, "Group");
 239         if (sd->sacl_offset != 0)
 240                 print_acl(p + sd->sacl_offset, "System");
 241         if (sd->dacl_offset != 0)
 242                 print_acl(p + sd->dacl_offset, "Discretionary");
 243 }
 244
 245 /*
 246  * Prints the security data for a WIM file.
 247  */
 248 void print_security_data(const struct wim_security_data *sd)
 249 {
 250         puts("[SECURITY DATA]");
 251         printf("Length            = %"PRIu32" bytes\n", sd->total_length);
 252         printf("Number of Entries = %"PRIu32"\n", sd->num_entries);
 253
 254         for (u32 i = 0; i < sd->num_entries; i++) {
 255                 printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n",
 256                        i, sd->sizes[i]);
 257                 print_security_descriptor(sd->descriptors[i], sd->sizes[i]);
 258                 putchar('\n');
 259         }
 260         putchar('\n');
 261 }
 262
 263 void free_security_data(struct wim_security_data *sd)
 264 {
 265         if (!sd)
 266                 return;
 267         wimlib_assert(sd->refcnt != 0);
 268         if (--sd->refcnt == 0) {
 269                 u8 **descriptors = sd->descriptors;
 270                 u32 num_entries  = sd->num_entries;
 271                 if (descriptors)
 272                         while (num_entries--)
 273                                 FREE(*descriptors++);
 274                 FREE(sd->sizes);
 275                 FREE(sd->descriptors);
 276                 FREE(sd);
 277         }
 278 }