]> wimlib.net Git - wimlib/blobdiff - src/security.c
Extract NTFS junction points correctly
[wimlib] / src / security.c
index cbf7fe0072d7d9d33f965cd1e6b236b4cd944b4b..bc44b45ae9d3707dea3fe6fb670e47d5c3d326f6 100644 (file)
@@ -3,23 +3,25 @@
  *
  * Read the security data from the WIM.  Doing anything with the security data
  * is not yet implemented other than printing some information about it.
- *
+ */
+
+/*
  * 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 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.
  *
- * 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 Lesser 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 Lesser General Public License
+ * along with wimlib; if not, see http://www.gnu.org/licenses/.
  */
 
 #include "wimlib_internal.h"
  *
  * @metadata_resource: An array that contains the uncompressed metadata
  *                             resource for the WIM file.
- * @metadata_resource_len:     The length of @metadata_resource.
- * @sd:                A pointer to a WIMSecurityData structure that is filled in with
- *             the security data.
- * @return:    True on success, false on failure.
+ * @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.
  */
-bool read_security_data(const u8 metadata_resource[], 
-               u64 metadata_resource_len, WIMSecurityData *sd)
+int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len,
+                      struct wim_security_data **sd_p)
 {
-       sd->num_entries = 0;
-       sd->descriptors = NULL;
-       sd->sizes       = NULL;
+       struct wim_security_data *sd;
+       const u8 *p;
+       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 false;
+       sd = MALLOC(sizeof(struct wim_security_data));
+       if (!sd) {
+               ERROR("Out of memory");
+               return WIMLIB_ERR_NOMEM;
        }
-       const u8 *p = metadata_resource;
+       sd->sizes       = NULL;
+       sd->descriptors = NULL;
+       sd->refcnt      = 1;
+
+       p = metadata_resource;
        p = get_u32(p, &sd->total_length);
        p = get_u32(p, &sd->num_entries);
 
        /* 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. */
-       u64 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_RESOURCE_SIZE;
+               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) {
-               sd->sizes = NULL;
-               sd->descriptors = NULL;
-               return true;
+               /* 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 there must be at least %"PRIu64" bytes of security "
-                               "data!\n", sd->total_length, 
-                               8 + sizes_size);
-               return false;
+       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_RESOURCE_SIZE;
+               goto out_free_sd;
        }
-       if (size_no_descriptors > 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, size_no_descriptors);
-               return false;
+       sd->sizes = MALLOC(sizes_size);
+       if (!sd->sizes) {
+               ret = WIMLIB_ERR_NOMEM;
+               goto out_free_sd;
        }
-       sd->sizes = xmalloc(sizes_size);
 
        /* 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);
 
        /* Allocate the array of pointers to descriptors, and read them in. */
-       sd->descriptors = xmalloc(sd->num_entries * sizeof(u8*));
-       u64 total_len = size_no_descriptors;
-
-       for (uint i = 0; i < sd->num_entries; i++) {
+       sd->descriptors = CALLOC(sd->num_entries, sizeof(u8*));
+       if (!sd->descriptors) {
+               ERROR("Out of memory while allocating security "
+                     "descriptors");
+               ret = WIMLIB_ERR_NOMEM;
+               goto out_free_sd;
+       }
+       total_len = size_no_descriptors;
 
+       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;
+               }
                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);
-                       sd->num_entries = i;
-                       return false;
+               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;
                }
-               if (total_len > metadata_resource_len) {
-                       sd->num_entries = i;
-                       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);
-                       return false;
+               sd->descriptors[i] = MALLOC(sd->sizes[i]);
+               if (!sd->descriptors[i]) {
+                       ERROR("Out of memory while allocating security "
+                             "descriptors");
+                       ret = WIMLIB_ERR_NOMEM;
+                       goto out_free_sd;
                }
-               sd->descriptors[i] = xmalloc(sd->sizes[i]);
                p = get_bytes(p, sd->sizes[i], sd->descriptors[i]);
        }
-
-       /* The total_length field seems to take into account padding for
-        * quadword alignment of the dentry following it, so we can ignore the
-        * case where the actual length read so far is less than the specified
-        * total length of the security data. */
-       #if 0
-       if (total_len < sd->total_length) {
-               /*ERROR("Warning: security data was actually %"PRIu64" bytes, but "*/
-                               /*"it says its length is %"PRIu64" bytes!\n",*/
-                               /*total_len, sd->total_length);*/
-       }
-       #endif
-
-       return true;
+out:
+       sd->total_length = (u32)total_len;
+       *sd_p = sd;
+       return 0;
+out_free_sd:
+       free_security_data(sd);
+       return ret;
 }
 
 /* 
- * Writes the security data to the output file.
- *
- * @sd:        The security data structure.
- * @out:       The FILE* for the output file.
- * @return:    True on success, false on failure.
+ * Writes security data to an in-memory buffer.
  */
-u8 *write_security_data(const WIMSecurityData *sd, u8 *p)
+u8 *write_security_data(const struct wim_security_data *sd, u8 *p)
 {
-       DEBUG("Writing security data (total_length = %u, num_entries = %u)\n",
-                       sd->total_length, sd->num_entries);
+       DEBUG("Writing security data (total_length = %"PRIu32", num_entries "
+             "= %"PRIu32")", sd->total_length, sd->num_entries);
+
        u8 *orig_p = p;
        p = put_u32(p, sd->total_length);
        p = put_u32(p, sd->num_entries);
 
-       for (uint i = 0; i < sd->num_entries; i++)
+       for (u32 i = 0; i < sd->num_entries; i++)
                p = put_u64(p, sd->sizes[i]);
 
-       for (uint i = 0; i < sd->num_entries; i++)
+       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);
+       wimlib_assert(p - orig_p == sd->total_length);
 
-       DEBUG("Successfully wrote security data.\n");
-       return orig_p + 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
@@ -225,44 +247,35 @@ static void print_security_descriptor(const u8 *p, u64 size)
 
 /* 
  * Prints the security data for a WIM file.
- *
- * @sd:        A pointer to the WIMSecurityData structure.
  */
-void print_security_data(const WIMSecurityData *sd)
+void print_security_data(const struct wim_security_data *sd)
 {
        puts("[SECURITY DATA]");
-       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]);
+       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');
 }
 
-void init_security_data(WIMSecurityData *sd)
+void free_security_data(struct wim_security_data *sd)
 {
-       sd->total_length = 8;
-       sd->num_entries  = 0;
-       sd->sizes        = NULL;
-       sd->descriptors  = NULL;
-       /* XXX figure out what the security descriptors actually do */
-}
-
-void destroy_security_data(WIMSecurityData *sd)
-{
-       u8 **descriptors = sd->descriptors;
-       u32 num_entries = sd->num_entries;
-       while (num_entries--)
-               FREE(*descriptors++);
-       sd->num_entries = 0;
-       FREE(sd->sizes);
-       sd->sizes = NULL;
-       FREE(sd->descriptors);
-       sd->descriptors = NULL;
+       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);
+       }
 }
-