X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Fsecurity.c;h=85cfb5bc6ce968f85671672577bd0c3984a69e41;hp=99f09134c18678aeea79a8adf49ea314276129c6;hb=d31b2fee211b1c31420bafe1c2379f6f89bd92fe;hpb=902a8bb8de242de08b29b995b69ae3e2a3495f6f diff --git a/src/security.c b/src/security.c index 99f09134..85cfb5bc 100644 --- a/src/security.c +++ b/src/security.c @@ -1,67 +1,104 @@ /* * 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. */ /* - * Copyright (C) 2012 Eric Biggers + * Copyright (C) 2012, 2013, 2014 Eric Biggers * - * This file is part of wimlib, a library for working with WIM files. + * This file 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 3 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. - * - * 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 + * This file 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 wimlib; if not, see http://www.gnu.org/licenses/. + * along with this file; 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. 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. + * @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 */ -int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, - struct wim_security_data **sd_p) +int +read_wim_security_data(const u8 *buf, size_t buf_len, + struct wim_security_data **sd_ret) { struct wim_security_data *sd; - const u8 *p; int ret; u64 total_len; + u64 sizes_size; + u64 size_no_descriptors; + const struct wim_security_data_disk *sd_disk; + const u8 *p; - sd = MALLOC(sizeof(struct wim_security_data)); - if (!sd) { - ERROR("Out of memory"); - return WIMLIB_ERR_NOMEM; - } - sd->sizes = NULL; - sd->descriptors = NULL; - sd->refcnt = 1; + 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 = ALIGN(le32_to_cpu(sd_disk->total_length), 8); + sd->num_entries = le32_to_cpu(sd_disk->num_entries); + + /* Length field of 0 is a special case that really means length + * of 8. */ + if (sd->total_length == 0) + sd->total_length = 8; - p = metadata_resource; - p = get_u32(p, &sd->total_length); - p = get_u32(p, &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) + 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 @@ -71,208 +108,285 @@ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, * 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; - } + if (sd->total_length > buf_len) + goto out_invalid_sd; - DEBUG("Reading security data: %u entries, length = %u", - sd->num_entries, sd->total_length); + 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) { - /* No security data. */ - total_len = 8; - goto out; - } + total_len = size_no_descriptors; - 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", - sd->total_length, 8 + sizes_size); - ret = WIMLIB_ERR_INVALID_RESOURCE_SIZE; - goto out_free_sd; - } + /* Return immediately if no security descriptors. */ + if (sd->num_entries == 0) + goto out_descriptors_ready; + + /* Allocate a new buffer for the sizes array */ sd->sizes = MALLOC(sizes_size); - if (!sd->sizes) { - ret = WIMLIB_ERR_NOMEM; - goto out_free_sd; - } + if (!sd->sizes) + goto out_of_memory; - /* 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 = 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; + /* 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; } - total_len = size_no_descriptors; + + 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++) { - /* 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; - } + if (sd->sizes[i] == 0) + continue; total_len += sd->sizes[i]; - 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; - } - 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; - } - 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]; } -out: - sd->total_length = (u32)total_len; - *sd_p = sd; - return 0; +out_descriptors_ready: + if (ALIGN(total_len, 8) != sd->total_length) { + WARNING("Stored WIM security data total length was " + "%"PRIu32" bytes, but calculated %"PRIu32" bytes", + sd->total_length, (u32)total_len); + } + *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_security_data(sd); + free_wim_security_data(sd); +out: return ret; } -/* - * Writes security data to an in-memory buffer. +/* + * Writes the security data for a WIM image to an in-memory buffer. */ -u8 *write_security_data(const struct wim_security_data *sd, u8 *p) +u8 * +write_wim_security_data(const struct wim_security_data * restrict sd, + u8 * restrict p) { - 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; - for (u32 i = 0; i < sd->num_entries; i++) - p = put_u64(p, sd->sizes[i]); + sd_disk->total_length = cpu_to_le32(sd->total_length); + sd_disk->num_entries = cpu_to_le32(num_entries); - for (u32 i = 0; i < sd->num_entries; i++) - p = put_bytes(p, sd->sizes[i], sd->descriptors[i]); + for (u32 i = 0; i < num_entries; i++) + sd_disk->sizes[i] = cpu_to_le64(sd->sizes[i]); - wimlib_assert(p - orig_p == sd->total_length); + p = (u8*)&sd_disk->sizes[num_entries]; - DEBUG("Successfully wrote security data."); + for (u32 i = 0; i < num_entries; i++) + p = mempcpy(p, sd->descriptors[i], sd->sizes[i]); + + while ((uintptr_t)p & 7) + *p++ = 0; + + wimlib_assert(p - orig_p == sd->total_length); return p; } -static void print_acl(const u8 *p, const char *type) +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 { + s32 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 +free_sd_tree(struct avl_tree_node *node) { - ACL *acl = (ACL*)p; - TO_LE16(acl->acl_size); - TO_LE16(acl->acl_count); - printf(" [%s ACL]\n", type); - 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)); } - putchar('\n'); } -static void print_sid(const u8 *p, const char *type) +void +rollback_new_security_descriptors(struct wim_sd_set *sd_set) +{ + 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; +} + +/* Frees a security descriptor index set. */ +void +destroy_sd_set(struct wim_sd_set *sd_set) +{ + free_sd_tree(sd_set->root); +} + +static int +_avl_cmp_nodes_by_hash(const struct avl_tree_node *n1, + const struct avl_tree_node *n2) { - SID *sid = (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)); - putchar('\n'); - for (uint i = 0; i < sid->sub_authority_count; i++) - printf(" Subauthority %u = %u\n", i, to_le32(sid->sub_authority[i])); - putchar('\n'); + return hashes_cmp(SD_NODE(n1)->hash, SD_NODE(n2)->hash); } -static void print_security_descriptor(const u8 *p, u64 size) +/* 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) { - 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 = %#x\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, "Owner"); - if (sd->group_offset != 0) - print_sid(p + sd->group_offset, "Group"); - if (sd->sacl_offset != 0) - print_acl(p + sd->sacl_offset, "System"); - if (sd->dacl_offset != 0) - print_acl(p + sd->dacl_offset, "Discretionary"); + return NULL == avl_tree_insert(&set->root, &new->index_node, + _avl_cmp_nodes_by_hash); } -/* - * Prints the security data for a WIM file. +/* Returns the index of the security descriptor having a SHA1 message digest of + * @hash. If not found, return -1. */ +static s32 +lookup_sd(struct wim_sd_set *set, const u8 hash[SHA1_HASH_SIZE]) +{ + 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. */ -void print_security_data(const struct wim_security_data *sd) +s32 +sd_set_add_sd(struct wim_sd_set *sd_set, const char *descriptor, size_t size) { - puts("[SECURITY DATA]"); - printf("Length = %"PRIu32" bytes\n", sd->total_length); - printf("Number of Entries = %"PRIu32"\n", sd->num_entries); + u8 hash[SHA1_HASH_SIZE]; + s32 security_id; + struct sd_node *new; + u8 **descriptors; + u64 *sizes; + u8 *descr_copy; + struct wim_security_data *sd; + bool bret; - 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'); + 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++; + 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; } -void free_security_data(struct wim_security_data *sd) +/* 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) { - 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); + 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; }