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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, (u32*)&sd->num_entries);
  65
  66         if (sd->num_entries > 0x7fffffff) {
  67                 ERROR("Security data has too many entries!");
  68                 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
  69                 goto out_free_sd;
  70         }
  71
  72         /* Verify the listed total length of the security data is big enough to
  73          * include the sizes array, verify that the file data is big enough to
  74          * include it as well, then allocate the array of sizes.
  75          *
  76          * Note: The total length of the security data must fit in a 32-bit
  77          * integer, even though each security descriptor size is a 64-bit
  78          * integer.  This is stupid, and we need to be careful not to actually
  79          * let the security descriptor sizes be over 0xffffffff.  */
  80         if ((u64)sd->total_length > metadata_resource_len) {
  81                 ERROR("Security data total length (%u) is bigger than the "
  82                       "metadata resource length (%"PRIu64")",
  83                       sd->total_length, metadata_resource_len);
  84                 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
  85                 goto out_free_sd;
  86         }
  87
  88         DEBUG("Reading security data: %u entries, length = %u",
  89               sd->num_entries, sd->total_length);
  90
  91         if (sd->num_entries == 0) {
  92                 /* No security data. */
  93                 total_len = 8;
  94                 goto out;
  95         }
  96
  97         u64 sizes_size = (u64)sd->num_entries * sizeof(u64);
  98         u64 size_no_descriptors = 8 + sizes_size;
  99         if (size_no_descriptors > (u64)sd->total_length) {
 100                 ERROR("Security data total length of %u is too short because "
 101                       "there must be at least %"PRIu64" bytes of security data",
 102                       sd->total_length, 8 + sizes_size);
 103                 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
 104                 goto out_free_sd;
 105         }
 106         sd->sizes = MALLOC(sizes_size);
 107         if (!sd->sizes) {
 108                 ret = WIMLIB_ERR_NOMEM;
 109                 goto out_free_sd;
 110         }
 111
 112         /* Copy the sizes array in from the file data. */
 113         p = get_bytes(p, sizes_size, sd->sizes);
 114         array_to_le64(sd->sizes, sd->num_entries);
 115
 116         /* Allocate the array of pointers to descriptors, and read them in. */
 117         sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*));
 118         if (!sd->descriptors) {
 119                 ERROR("Out of memory while allocating security "
 120                       "descriptors");
 121                 ret = WIMLIB_ERR_NOMEM;
 122                 goto out_free_sd;
 123         }
 124         total_len = size_no_descriptors;
 125
 126         for (u32 i = 0; i < sd->num_entries; i++) {
 127                 /* Watch out for huge security descriptor sizes that could
 128                  * overflow the total length and wrap it around. */
 129                 if (total_len + sd->sizes[i] < total_len) {
 130                         ERROR("Caught overflow in security descriptor lengths "
 131                               "(current total length = %"PRIu64", security "
 132                               "descriptor size = %"PRIu64")",
 133                               total_len, sd->sizes[i]);
 134                         ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
 135                         goto out_free_sd;
 136                 }
 137                 total_len += sd->sizes[i];
 138                 if (total_len > (u64)sd->total_length) {
 139                         ERROR("Security data total length of %u is too short "
 140                               "because there are at least %"PRIu64" bytes of "
 141                               "security data", sd->total_length, total_len);
 142                         ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
 143                         goto out_free_sd;
 144                 }
 145                 sd->descriptors[i] = MALLOC(sd->sizes[i]);
 146                 if (!sd->descriptors[i]) {
 147                         ERROR("Out of memory while allocating security "
 148                               "descriptors");
 149                         ret = WIMLIB_ERR_NOMEM;
 150                         goto out_free_sd;
 151                 }
 152                 p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
 153         }
 154 out:
 155         sd->total_length = (u32)total_len;
 156         *sd_p = sd;
 157         return 0;
 158 out_free_sd:
 159         free_security_data(sd);
 160         return ret;
 161 }
 162
 163 /*
 164  * Writes security data to an in-memory buffer.
 165  */
 166 u8 *write_security_data(const struct wim_security_data *sd, u8 *p)
 167 {
 168         DEBUG("Writing security data (total_length = %"PRIu32", num_entries "
 169               "= %"PRIu32")", sd->total_length, sd->num_entries);
 170
 171         u32 aligned_length = (sd->total_length + 7) & ~7;
 172
 173         u8 *orig_p = p;
 174         p = put_u32(p, aligned_length);
 175         p = put_u32(p, sd->num_entries);
 176
 177         for (u32 i = 0; i < sd->num_entries; i++)
 178                 p = put_u64(p, sd->sizes[i]);
 179
 180         for (u32 i = 0; i < sd->num_entries; i++)
 181                 p = put_bytes(p, sd->sizes[i], sd->descriptors[i]);
 182
 183         wimlib_assert(p - orig_p == sd->total_length);
 184         p = put_zeroes(p, aligned_length - sd->total_length);
 185
 186         DEBUG("Successfully wrote security data.");
 187         return p;
 188 }
 189
 190 static void print_acl(const u8 *p, const char *type)
 191 {
 192         ACL *acl = (ACL*)p;
 193         TO_LE16(acl->acl_size);
 194         TO_LE16(acl->acl_count);
 195         printf("    [%s ACL]\n", type);
 196         printf("    Revision = %u\n", acl->revision);
 197         printf("    ACL Size = %u\n", acl->acl_size);
 198         printf("    ACE Count = %u\n", acl->ace_count);
 199
 200         p += sizeof(ACL);
 201         for (uint i = 0; i < acl->ace_count; i++) {
 202                 ACEHeader *hdr = (ACEHeader*)p;
 203                 printf("        [ACE]\n");
 204                 printf("        ACE type  = %d\n", hdr->type);
 205                 printf("        ACE flags = 0x%x\n", hdr->flags);
 206                 printf("        ACE size  = %u\n", hdr->size);
 207                 AccessAllowedACE *aaa = (AccessAllowedACE*)hdr;
 208                 printf("        ACE mask = %x\n", to_le32(aaa->mask));
 209                 printf("        SID start = %u\n", to_le32(aaa->sid_start));
 210                 p += hdr->size;
 211         }
 212         putchar('\n');
 213 }
 214
 215 static void print_sid(const u8 *p, const char *type)
 216 {
 217         SID *sid = (SID*)p;
 218         printf("    [%s SID]\n", type);
 219         printf("    Revision = %u\n", sid->revision);
 220         printf("    Subauthority count = %u\n", sid->sub_authority_count);
 221         printf("    Identifier authority = ");
 222         print_byte_field(sid->identifier_authority, sizeof(sid->identifier_authority));
 223         putchar('\n');
 224         for (uint i = 0; i < sid->sub_authority_count; i++)
 225                 printf("    Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i]));
 226         putchar('\n');
 227 }
 228
 229 static void print_security_descriptor(const u8 *p, u64 size)
 230 {
 231         SecurityDescriptor *sd = (SecurityDescriptor*)p;
 232         TO_LE16(sd->security_descriptor_control);
 233         TO_LE32(sd->owner_offset);
 234         TO_LE32(sd->group_offset);
 235         TO_LE32(sd->sacl_offset);
 236         TO_LE32(sd->dacl_offset);
 237         printf("Revision = %u\n", sd->revision);
 238         printf("Security Descriptor Control = %#x\n", sd->security_descriptor_control);
 239         printf("Owner offset = %u\n", sd->owner_offset);
 240         printf("Group offset = %u\n", sd->group_offset);
 241         printf("System ACL offset = %u\n", sd->sacl_offset);
 242         printf("Discretionary ACL offset = %u\n", sd->dacl_offset);
 243
 244         if (sd->owner_offset != 0)
 245                 print_sid(p + sd->owner_offset, "Owner");
 246         if (sd->group_offset != 0)
 247                 print_sid(p + sd->group_offset, "Group");
 248         if (sd->sacl_offset != 0)
 249                 print_acl(p + sd->sacl_offset, "System");
 250         if (sd->dacl_offset != 0)
 251                 print_acl(p + sd->dacl_offset, "Discretionary");
 252 }
 253
 254 /*
 255  * Prints the security data for a WIM file.
 256  */
 257 void print_security_data(const struct wim_security_data *sd)
 258 {
 259         puts("[SECURITY DATA]");
 260         printf("Length            = %"PRIu32" bytes\n", sd->total_length);
 261         printf("Number of Entries = %"PRIu32"\n", sd->num_entries);
 262
 263         for (u32 i = 0; i < sd->num_entries; i++) {
 264                 printf("[SecurityDescriptor %"PRIu32", length = %"PRIu64"]\n",
 265                        i, sd->sizes[i]);
 266                 print_security_descriptor(sd->descriptors[i], sd->sizes[i]);
 267                 putchar('\n');
 268         }
 269         putchar('\n');
 270 }
 271
 272 void free_security_data(struct wim_security_data *sd)
 273 {
 274         if (!sd)
 275                 return;
 276         wimlib_assert(sd->refcnt != 0);
 277         if (--sd->refcnt == 0) {
 278                 u8 **descriptors = sd->descriptors;
 279                 u32 num_entries  = sd->num_entries;
 280                 if (descriptors)
 281                         while (num_entries--)
 282                                 FREE(*descriptors++);
 283                 FREE(sd->sizes);
 284                 FREE(sd->descriptors);
 285                 FREE(sd);
 286         }
 287 }