X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=e6a7e93a84d6001ed47f55afdfdfd8d3e2c1f395;hp=cbf7fe0072d7d9d33f965cd1e6b236b4cd944b4b;hb=76b57cc8cf113194136a7e264644a37515650ccc;hpb=885632f08c75c1d7bb5d25436231c78f6ad7e0c0 diff --git a/src/security.c b/src/security.c index cbf7fe00..e6a7e93a 100644 --- a/src/security.c +++ b/src/security.c @@ -1,268 +1,405 @@ /* * 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. - * - * Copyright (C) 2012 Eric Biggers + * Read and write the per-WIM-image table of security descriptors. + */ + +/* + * Copyright (C) 2012, 2013, 2014 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 HAVE_CONFIG_H +# include "config.h" +#endif + +#include "wimlib/assert.h" +#include "wimlib/avl_tree.h" +#include "wimlib/endianness.h" +#include "wimlib/error.h" +#include "wimlib/security.h" +#include "wimlib/sha1.h" +#include "wimlib/util.h" + +struct wim_security_data_disk { + le32 total_length; + le32 num_entries; + le64 sizes[]; +} _packed_attribute; + +struct wim_security_data * +new_wim_security_data(void) +{ + return CALLOC(1, sizeof(struct wim_security_data)); +} -/* - * Reads the security data from the metadata resource. +/* + * Reads the security data from the metadata resource of a WIM image. * - * @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. + * @buf + * Buffer containing an uncompressed WIM metadata resource. + * @buf_len + * Length of the uncompressed metadata resource, in bytes. + * @sd_ret + * On success, a pointer to the resulting security data structure will be + * returned here. * * Note: There is no `offset' argument because the security data is located at * the beginning of the metadata resource. + * + * Return values: + * WIMLIB_ERR_SUCCESS (0) + * WIMLIB_ERR_INVALID_METADATA_RESOURCE + * WIMLIB_ERR_NOMEM */ -bool read_security_data(const u8 metadata_resource[], - u64 metadata_resource_len, WIMSecurityData *sd) +int +read_wim_security_data(const u8 *buf, size_t buf_len, + struct wim_security_data **sd_ret) { - sd->num_entries = 0; - sd->descriptors = NULL; - sd->sizes = NULL; - - if (metadata_resource_len < 8) { - ERROR("Not enough space in %"PRIu64"-byte file resource for " - "security data!\n", metadata_resource_len); - return false; - } - const u8 *p = metadata_resource; - p = get_u32(p, &sd->total_length); - p = get_u32(p, &sd->num_entries); + struct wim_security_data *sd; + int ret; + u64 total_len; + u64 sizes_size; + u64 size_no_descriptors; + const struct wim_security_data_disk *sd_disk; + const u8 *p; + + if (buf_len < 8) + return WIMLIB_ERR_INVALID_METADATA_RESOURCE; + + sd = new_wim_security_data(); + if (!sd) + goto out_of_memory; + + sd_disk = (const struct wim_security_data_disk *)buf; + sd->total_length = le32_to_cpu(sd_disk->total_length); + sd->num_entries = le32_to_cpu(sd_disk->num_entries); + + DEBUG("Reading security data: num_entries=%u, total_length=%u", + sd->num_entries, sd->total_length); + + /* Length field of 0 is a special case that really means length + * of 8. */ + if (sd->total_length == 0) + sd->total_length = 8; + + /* 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) + 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 - * 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 (sd->total_length > buf_len) + goto out_invalid_sd; - DEBUG("Reading security data with %u entries\n", sd->num_entries); + sizes_size = (u64)sd->num_entries * sizeof(u64); + size_no_descriptors = 8 + sizes_size; + if (size_no_descriptors > sd->total_length) + goto out_invalid_sd; - if (sd->num_entries == 0) { - sd->sizes = NULL; - sd->descriptors = NULL; - return true; - } + total_len = size_no_descriptors; - 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 > 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 = xmalloc(sizes_size); + /* Return immediately if no security descriptors. */ + if (sd->num_entries == 0) + goto out_align_total_length; - /* 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 a new buffer for the sizes array */ + sd->sizes = MALLOC(sizes_size); + if (!sd->sizes) + goto out_of_memory; - /* 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; + /* Copy the sizes array into the new buffer */ + for (u32 i = 0; i < sd->num_entries; i++) { + sd->sizes[i] = le64_to_cpu(sd_disk->sizes[i]); + if (sd->sizes[i] > 0xffffffff) + goto out_invalid_sd; + } - for (uint i = 0; i < sd->num_entries; i++) { + p = (const u8*)sd_disk + size_no_descriptors; + /* Allocate the array of pointers to the security descriptors, then read + * them into separate buffers. */ + sd->descriptors = CALLOC(sd->num_entries, sizeof(sd->descriptors[0])); + if (!sd->descriptors) + goto out_of_memory; + + for (u32 i = 0; i < sd->num_entries; i++) { + if (sd->sizes[i] == 0) + continue; 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 > 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] = xmalloc(sd->sizes[i]); - p = get_bytes(p, sd->sizes[i], sd->descriptors[i]); + if (total_len > (u64)sd->total_length) + goto out_invalid_sd; + sd->descriptors[i] = memdup(p, sd->sizes[i]); + if (!sd->descriptors[i]) + goto out_of_memory; + p += sd->sizes[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);*/ +out_align_total_length: + total_len = (total_len + 7) & ~7; + sd->total_length = (sd->total_length + 7) & ~7; + if (total_len != sd->total_length) { + WARNING("Expected WIM security data total length of " + "%u bytes, but calculated %u bytes", + sd->total_length, (unsigned)total_len); } - #endif - - return true; + *sd_ret = sd; + ret = 0; + goto out; +out_invalid_sd: + ERROR("WIM security data is invalid!"); + ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE; + goto out_free_sd; +out_of_memory: + ERROR("Out of memory while reading WIM security data!"); + ret = WIMLIB_ERR_NOMEM; +out_free_sd: + free_wim_security_data(sd); +out: + 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 the security data for a WIM image to an in-memory buffer. */ -u8 *write_security_data(const WIMSecurityData *sd, u8 *p) +u8 * +write_wim_security_data(const struct wim_security_data * restrict sd, + u8 * restrict 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); + struct wim_security_data_disk *sd_disk = (struct wim_security_data_disk*)p; + u32 num_entries = sd->num_entries; + + sd_disk->total_length = cpu_to_le32(sd->total_length); + sd_disk->num_entries = cpu_to_le32(num_entries); + + for (u32 i = 0; i < num_entries; i++) + sd_disk->sizes[i] = cpu_to_le64(sd->sizes[i]); + + p = (u8*)&sd_disk->sizes[num_entries]; - for (uint i = 0; i < sd->num_entries; i++) - p = put_u64(p, sd->sizes[i]); + for (u32 i = 0; i < num_entries; i++) + p = mempcpy(p, sd->descriptors[i], sd->sizes[i]); - for (uint i = 0; i < sd->num_entries; i++) - p = put_bytes(p, sd->sizes[i], sd->descriptors[i]); + while ((uintptr_t)p & 7) + *p++ = 0; - 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 - * 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... */ +void +free_wim_security_data(struct wim_security_data *sd) +{ + if (sd) { + 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); + } +} + +struct sd_node { + int32_t security_id; + u8 hash[SHA1_HASH_SIZE]; + struct avl_tree_node index_node; +}; + +#define SD_NODE(avl_node) \ + avl_tree_entry(avl_node, struct sd_node, index_node) -static void print_acl(const u8 *p) +static void +free_sd_tree(struct avl_tree_node *node) { - 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); - - p += sizeof(ACL); - for (uint i = 0; i < acl->ace_count; i++) { - ACEHeader *hdr = (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)); - p += hdr->size; + if (node) { + free_sd_tree(node->left); + free_sd_tree(node->right); + FREE(SD_NODE(node)); } } -static void print_sid(const u8 *p) +void +rollback_new_security_descriptors(struct wim_sd_set *sd_set) { - SID *sid = (SID*)p; - printf(" [SID]\n"); - 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)); - putchar('\n'); - for (uint i = 0; i < sid->sub_authority_count; i++) - printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i])); + struct wim_security_data *sd = sd_set->sd; + u8 **descriptors = sd->descriptors + sd_set->orig_num_entries; + u32 num_entries = sd->num_entries - sd_set->orig_num_entries; + while (num_entries--) + FREE(*descriptors++); + sd->num_entries = sd_set->orig_num_entries; } -static void print_security_descriptor(const u8 *p, u64 size) +/* Frees a security descriptor index set. */ +void +destroy_sd_set(struct wim_sd_set *sd_set) { - 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); - - if (sd->owner_offset != 0) - print_sid(p + sd->owner_offset); - if (sd->group_offset != 0) - print_sid(p + sd->group_offset); - if (sd->sacl_offset != 0) - print_acl(p + sd->sacl_offset); - if (sd->dacl_offset != 0) - print_acl(p + sd->dacl_offset); + free_sd_tree(sd_set->root); } -/* - * Prints the security data for a WIM file. - * - * @sd: A pointer to the WIMSecurityData structure. - */ -void print_security_data(const WIMSecurityData *sd) +static int +_avl_cmp_nodes_by_hash(const struct avl_tree_node *n1, + const struct avl_tree_node *n2) { - puts("[SECURITY DATA]"); - printf("Length = %u bytes\n", sd->total_length); - printf("Number of Entries = %u\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'); - } - putchar('\n'); + return hashes_cmp(SD_NODE(n1)->hash, SD_NODE(n2)->hash); } -void init_security_data(WIMSecurityData *sd) +/* Inserts a new node into the security descriptor index tree. Returns true + * if successful (not a duplicate). */ +static bool +insert_sd_node(struct wim_sd_set *set, struct sd_node *new) { - sd->total_length = 8; - sd->num_entries = 0; - sd->sizes = NULL; - sd->descriptors = NULL; - /* XXX figure out what the security descriptors actually do */ + return NULL == avl_tree_insert(&set->root, &new->index_node, + _avl_cmp_nodes_by_hash); } -void destroy_security_data(WIMSecurityData *sd) +/* Returns the index of the security descriptor having a SHA1 message digest of + * @hash. If not found, return -1. */ +static int32_t +lookup_sd(struct wim_sd_set *set, const u8 hash[SHA1_HASH_SIZE]) { - 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; + struct avl_tree_node *res; + struct sd_node dummy; + + copy_hash(dummy.hash, hash); + res = avl_tree_lookup_node(set->root, &dummy.index_node, + _avl_cmp_nodes_by_hash); + if (!res) + return -1; + return SD_NODE(res)->security_id; } +/* + * Adds a security descriptor to the indexed security descriptor set as well as + * the corresponding `struct wim_security_data', and returns the new security + * ID; or, if there is an existing security descriptor that is the same, return + * the security ID for it. If a new security descriptor cannot be allocated, + * return -1. + */ +int32_t +sd_set_add_sd(struct wim_sd_set *sd_set, const char *descriptor, size_t size) +{ + u8 hash[SHA1_HASH_SIZE]; + int32_t security_id; + struct sd_node *new; + u8 **descriptors; + u64 *sizes; + u8 *descr_copy; + struct wim_security_data *sd; + bool bret; + + sha1_buffer(descriptor, size, hash); + + security_id = lookup_sd(sd_set, hash); + if (security_id >= 0) /* Identical descriptor already exists */ + goto out; + + /* Need to add a new security descriptor */ + security_id = -1; + + new = MALLOC(sizeof(*new)); + if (!new) + goto out; + + descr_copy = memdup(descriptor, size); + if (!descr_copy) + goto out_free_node; + + sd = sd_set->sd; + new->security_id = sd->num_entries; + copy_hash(new->hash, hash); + + /* There typically are only a few dozen security descriptors in a + * directory tree, so expanding the array of security descriptors by + * only 1 extra space each time should not be a problem. */ + descriptors = REALLOC(sd->descriptors, + (sd->num_entries + 1) * sizeof(sd->descriptors[0])); + if (!descriptors) + goto out_free_descr; + sd->descriptors = descriptors; + sizes = REALLOC(sd->sizes, + (sd->num_entries + 1) * sizeof(sd->sizes[0])); + if (!sizes) + goto out_free_descr; + sd->sizes = sizes; + sd->descriptors[sd->num_entries] = descr_copy; + sd->sizes[sd->num_entries] = size; + sd->num_entries++; + DEBUG("There are now %u security descriptors", sd->num_entries); + bret = insert_sd_node(sd_set, new); + wimlib_assert(bret); + security_id = new->security_id; + goto out; +out_free_descr: + FREE(descr_copy); +out_free_node: + FREE(new); +out: + return security_id; +} + +/* Initialize a `struct sd_set' mapping from SHA1 message digests of security + * descriptors to indices into the security descriptors table of the WIM image + * (security IDs). */ +int +init_sd_set(struct wim_sd_set *sd_set, struct wim_security_data *sd) +{ + int ret; + + sd_set->sd = sd; + sd_set->root = NULL; + + /* Remember the original number of security descriptors so that newly + * added ones can be rolled back if needed. */ + sd_set->orig_num_entries = sd->num_entries; + for (u32 i = 0; i < sd->num_entries; i++) { + struct sd_node *new; + + new = MALLOC(sizeof(struct sd_node)); + if (!new) { + ret = WIMLIB_ERR_NOMEM; + goto out_destroy_sd_set; + } + sha1_buffer(sd->descriptors[i], sd->sizes[i], new->hash); + new->security_id = i; + if (!insert_sd_node(sd_set, new)) + FREE(new); /* Ignore duplicate security descriptor */ + } + ret = 0; + goto out; +out_destroy_sd_set: + destroy_sd_set(sd_set); +out: + return ret; +}