/* * security.c * * Read and write the per-WIM-image table of security descriptors. */ /* * Copyright (C) 2012, 2013 Eric Biggers * * This file is part of wimlib, a library for working with WIM files. * * 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. * * 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 General Public License * along with wimlib; if not, see http://www.gnu.org/licenses/. */ #include "wimlib_internal.h" #include "buffer_io.h" #include "security.h" #define SECURITY_DESCRIPTOR_REVISION 1 #define SECURITY_DESCRIPTOR_REVISION1 1 /* inherit AceFlags */ #define OBJECT_INHERIT_ACE 0x01 #define CONTAINER_INHERIT_ACE 0x02 #define NO_PROPAGATE_INHERIT_ACE 0x04 #define INHERIT_ONLY_ACE 0x08 #define INHERITED_ACE 0x10 #define VALID_INHERIT_FLAGS 0x1F #define SE_OWNER_DEFAULTED 0x00000001 #define SE_GROUP_DEFAULTED 0x00000002 #define SE_DACL_PRESENT 0x00000004 #define SE_DACL_DEFAULTED 0x00000008 #define SE_SACL_PRESENT 0x00000010 #define SE_SACL_DEFAULTED 0x00000020 #define SE_DACL_AUTO_INHERIT_REQ 0x00000100 #define SE_SACL_AUTO_INHERIT_REQ 0x00000200 #define SE_DACL_AUTO_INHERITED 0x00000400 #define SE_SACL_AUTO_INHERITED 0x00000800 #define SE_DACL_PROTECTED 0x00001000 #define SE_SACL_PROTECTED 0x00002000 #define SE_RM_CONTROL_VALID 0x00004000 #define SE_SELF_RELATIVE 0x00008000 /* Flags in access control entries */ #define DELETE 0x00010000 #define READ_CONTROL 0x00020000 #define WRITE_DAC 0x00040000 #define WRITE_OWNER 0x00080000 #define SYNCHRONIZE 0x00100000 #define STANDARD_RIGHTS_REQUIRED 0x000f0000 #define STANDARD_RIGHTS_READ READ_CONTROL #define STANDARD_RIGHTS_WRITE READ_CONTROL #define STANDARD_RIGHTS_EXECUTE READ_CONTROL #define STANDARD_RIGHTS_ALL 0x001f0000 #define SPECIFIC_RIGHTS_ALL 0x0000ffff #define GENERIC_READ 0x80000000 #define GENERIC_WRITE 0x40000000 #define GENERIC_EXECUTE 0x20000000 #define GENERIC_ALL 0x10000000 #define MAXIMUM_ALLOWED 0x02000000 #define ACCESS_SYSTEM_SECURITY 0x01000000 #define EVENT_QUERY_STATE 0x0001 #define EVENT_MODIFY_STATE 0x0002 #define EVENT_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x3) #define SEMAPHORE_MODIFY_STATE 0x0002 #define SEMAPHORE_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x3) #define MUTEX_MODIFY_STATE 0x0001 #define MUTEX_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x1) #define JOB_OBJECT_ASSIGN_PROCESS 0x0001 #define JOB_OBJECT_SET_ATTRIBUTES 0x0002 #define JOB_OBJECT_QUERY 0x0004 #define JOB_OBJECT_TERMINATE 0x0008 #define JOB_OBJECT_SET_SECURITY_ATTRIBUTES 0x0010 #define JOB_OBJECT_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x1f) #define TIMER_QUERY_STATE 0x0001 #define TIMER_MODIFY_STATE 0x0002 #define TIMER_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x3) #define PROCESS_TERMINATE 0x0001 #define PROCESS_CREATE_THREAD 0x0002 #define PROCESS_VM_OPERATION 0x0008 #define PROCESS_VM_READ 0x0010 #define PROCESS_VM_WRITE 0x0020 #define PROCESS_DUP_HANDLE 0x0040 #define PROCESS_CREATE_PROCESS 0x0080 #define PROCESS_SET_QUOTA 0x0100 #define PROCESS_SET_INFORMATION 0x0200 #define PROCESS_QUERY_INFORMATION 0x0400 #define PROCESS_SUSPEND_RESUME 0x0800 #define PROCESS_QUERY_LIMITED_INFORMATION 0x1000 #define PROCESS_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0xfff) #define THREAD_TERMINATE 0x0001 #define THREAD_SUSPEND_RESUME 0x0002 #define THREAD_GET_CONTEXT 0x0008 #define THREAD_SET_CONTEXT 0x0010 #define THREAD_SET_INFORMATION 0x0020 #define THREAD_QUERY_INFORMATION 0x0040 #define THREAD_SET_THREAD_TOKEN 0x0080 #define THREAD_IMPERSONATE 0x0100 #define THREAD_DIRECT_IMPERSONATION 0x0200 #define THREAD_ALL_ACCESS (STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|0x3ff) #define THREAD_BASE_PRIORITY_LOWRT 15 #define THREAD_BASE_PRIORITY_MAX 2 #define THREAD_BASE_PRIORITY_MIN -2 #define THREAD_BASE_PRIORITY_IDLE -15 /* predefined authority values for SID's (security identifiers) */ enum sid_authority_value { SECURITY_NULL_SID_AUTHORITY = 0, SECURITY_WORLD_SID_AUTHORITY = 1, SECURITY_LOCAL_SID_AUTHORITY = 2, SECURITY_CREATOR_SID_AUTHORITY = 3, SECURITY_NON_UNIQUE_AUTHORITY = 4, SECURITY_NT_AUTHORITY = 5, }; /* local administrators group */ #define SECURITY_BUILTIN_DOMAIN_RID 32 #define DOMAIN_ALIAS_RID_ADMINS 544 /* See ACEHeader. */ enum ace_type { ACCESS_ALLOWED_ACE_TYPE = 0, ACCESS_DENIED_ACE_TYPE = 1, SYSTEM_AUDIT_ACE_TYPE = 2, }; /* At the start of each type of access control entry. */ typedef struct { /* enum ace_type, specifies what type of ACE this is. */ u8 type; /* bitwise OR of the inherit ACE flags #defined above */ u8 flags; /* Size of the access control entry. */ u8 size; } ACEHeader; /* Grants rights to a user or group */ typedef struct { ACEHeader hdr; u32 mask; u32 sid_start; } AccessAllowedACE; /* Denies rights to a user or group */ typedef struct { ACEHeader hdr; u32 mask; u32 sid_start; } AccessDeniedACE; typedef struct { ACEHeader hdr; u32 mask; u32 sid_start; } SystemAuditACE; /* Header of an access control list. */ typedef struct { /* ACL_REVISION or ACL_REVISION_DS */ u8 revision; /* padding */ u8 sbz1; /* Total size of the ACL, including all access control entries */ u16 acl_size; /* Number of access control entry structures that follow the ACL * structure. */ u16 ace_count; /* padding */ u16 sbz2; } ACL; /* A structure used to identify users or groups. */ typedef struct { /* example: 0x1 */ u8 revision; u8 sub_authority_count; /* Identifies the authority that issued the SID. Can be, but does not * have to be, one of enum sid_authority_value */ u8 identifier_authority[6]; u32 sub_authority[0]; } SID; typedef struct { /* Example: 0x1 */ u8 revision; /* Example: 0x0 */ u8 sbz1; /* Example: 0x4149 */ u16 security_descriptor_control; /* Offset of a SID structure in the security descriptor. */ /* Example: 0x14 */ u32 owner_offset; /* Offset of a SID structure in the security descriptor. */ /* Example: 0x24 */ u32 group_offset; /* Offset of an ACL structure in the security descriptor. */ /* System ACL. */ /* Example: 0x00 */ u32 sacl_offset; /* Offset of an ACL structure in the security descriptor. */ /* Discretionary ACL. */ /* Example: 0x34 */ u32 dacl_offset; } SecurityDescriptor; /* * This is a hack to work around a problem in libntfs-3g. libntfs-3g validates * security descriptors with a function named ntfs_valid_descr(). * ntfs_valid_descr() considers a security descriptor that ends in a SACL * (Sysetm Access Control List) with no ACE's (Access Control Entries) to be * invalid. However, a security descriptor like this exists in the Windows 7 * install.wim. Here, security descriptors matching this pattern are modified * to have no SACL. This should make no difference since the SACL had no * entries anyway; however this ensures that that the security descriptors pass * the validation in libntfs-3g. */ static void empty_sacl_fixup(u8 *descr, u64 *size_p) { /* No-op if no NTFS-3g support, or if NTFS-3g is version 2013 or later * */ #if defined(WITH_NTFS_3G) && !defined(HAVE_NTFS_MNT_RDONLY) if (*size_p >= sizeof(SecurityDescriptor)) { SecurityDescriptor *sd = (SecurityDescriptor*)descr; u32 sacl_offset = le32_to_cpu(sd->sacl_offset); if (sacl_offset == *size_p - sizeof(ACL)) { sd->sacl_offset = cpu_to_le32(0); *size_p -= sizeof(ACL); } } #endif } /* * Reads the security data from the metadata resource. * * @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. * * Note: There is no `offset' argument because the security data is located at * the beginning of the metadata resource. */ int read_security_data(const u8 metadata_resource[], u64 metadata_resource_len, struct wim_security_data **sd_p) { struct wim_security_data *sd; const u8 *p; int ret; u64 total_len; wimlib_assert(metadata_resource_len >= 8); /* * Sorry this function is excessively complicated--- I'm just being * extremely careful about integer overflows. */ 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; p = metadata_resource; p = get_u32(p, &sd->total_length); p = get_u32(p, (u32*)&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) { ERROR("Security data has too many entries!"); 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. * * 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); goto out_invalid_sd; } DEBUG("Reading security data: %u entries, length = %u", sd->num_entries, sd->total_length); if (sd->num_entries == 0) { /* No security descriptors. We allow the total_length field to * be either 8 (which is correct, since there are always 2 * 32-bit integers) or 0. */ if (sd->total_length != 0 && sd->total_length != 8) { ERROR("Invalid security data length (%u): expected 0 or 8", sd->total_length); goto out_invalid_sd; } sd->total_length = 8; goto out_return_sd; } 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 seem to be at least %"PRIu64" bytes of security data", sd->total_length, 8 + sizes_size); goto out_invalid_sd; } sd->sizes = MALLOC(sizes_size); if (!sd->sizes) { ret = WIMLIB_ERR_NOMEM; goto out_free_sd; } /* Copy the sizes array in from the file data. */ p = get_bytes(p, sizes_size, sd->sizes); array_le64_to_cpu(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; } 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]); goto out_invalid_sd; } total_len += sd->sizes[i]; /* This check ensures that the descriptor size fits in a 32 bit * integer. Because if it didn't, the total length would come * out bigger than sd->total_length, which is a 32 bit integer. * */ if (total_len > (u64)sd->total_length) { ERROR("Security data total length of %u is too short " "because there seem to be at least %"PRIu64" " "bytes of security data", sd->total_length, total_len); goto out_invalid_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]); empty_sacl_fixup(sd->descriptors[i], &sd->sizes[i]); } wimlib_assert(total_len <= 0xffffffff); if (((total_len + 7) & ~7) != ((sd->total_length + 7) & ~7)) { ERROR("Expected security data total length = %u, but " "calculated %u", sd->total_length, (unsigned)total_len); goto out_invalid_sd; } sd->total_length = total_len; out_return_sd: *sd_p = sd; return 0; out_invalid_sd: ret = WIMLIB_ERR_INVALID_SECURITY_DATA; out_free_sd: free_security_data(sd); return ret; } /* * Writes security data to an in-memory buffer. */ u8 * write_security_data(const struct wim_security_data *sd, u8 *p) { DEBUG("Writing security data (total_length = %"PRIu32", num_entries " "= %"PRIu32")", sd->total_length, sd->num_entries); u32 aligned_length = (sd->total_length + 7) & ~7; u8 *orig_p = p; p = put_u32(p, aligned_length); p = put_u32(p, sd->num_entries); for (u32 i = 0; i < sd->num_entries; i++) p = put_u64(p, sd->sizes[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); p = put_zeroes(p, aligned_length - sd->total_length); DEBUG("Successfully wrote security data."); return p; } static void print_acl(const u8 *p, const char *type) { const ACL *acl = (const ACL*)p; u8 revision = acl->revision; u16 acl_size = le16_to_cpu(acl->acl_size); u16 ace_count = le16_to_cpu(acl->ace_count); printf(" [%s ACL]\n", type); printf(" Revision = %u\n", revision); printf(" ACL Size = %u\n", acl_size); printf(" ACE Count = %u\n", ace_count); p += sizeof(ACL); for (u16 i = 0; i < ace_count; i++) { const ACEHeader *hdr = (const 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); const AccessAllowedACE *aaa = (const AccessAllowedACE*)hdr; printf(" ACE mask = %x\n", le32_to_cpu(aaa->mask)); printf(" SID start = %u\n", le32_to_cpu(aaa->sid_start)); p += hdr->size; } putchar('\n'); } static void print_sid(const u8 *p, const char *type) { const SID *sid = (const 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 (u8 i = 0; i < sid->sub_authority_count; i++) printf(" Subauthority %u = %u\n", i, le32_to_cpu(sid->sub_authority[i])); putchar('\n'); } static void print_security_descriptor(const u8 *p, u64 size) { const SecurityDescriptor *sd = (const SecurityDescriptor*)p; u8 revision = sd->revision; u16 control = le16_to_cpu(sd->security_descriptor_control); u32 owner_offset = le32_to_cpu(sd->owner_offset); u32 group_offset = le32_to_cpu(sd->group_offset); u32 sacl_offset = le32_to_cpu(sd->sacl_offset); u32 dacl_offset = le32_to_cpu(sd->dacl_offset); printf("Revision = %u\n", revision); printf("Security Descriptor Control = %#x\n", control); printf("Owner offset = %u\n", owner_offset); printf("Group offset = %u\n", group_offset); printf("System ACL offset = %u\n", sacl_offset); printf("Discretionary ACL offset = %u\n", dacl_offset); if (sd->owner_offset != 0) print_sid(p + owner_offset, "Owner"); if (sd->group_offset != 0) print_sid(p + group_offset, "Group"); if (sd->sacl_offset != 0) print_acl(p + sacl_offset, "System"); if (sd->dacl_offset != 0) print_acl(p + dacl_offset, "Discretionary"); } /* * Prints the security data for a WIM file. */ void print_security_data(const struct wim_security_data *sd) { wimlib_assert(sd != NULL); puts("[SECURITY DATA]"); printf("Length = %"PRIu32" bytes\n", sd->total_length); printf("Number of Entries = %"PRIu32"\n", sd->num_entries); 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 free_security_data(struct wim_security_data *sd) { if (sd) { 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); } } } /* The security tree stuff is only needed when NTFS capture is supported, either * through NTFS-3G or through a native Windows build. */ #if defined(WITH_NTFS_3G) || defined(__WIN32__) struct sd_node { int security_id; u8 hash[SHA1_HASH_SIZE]; struct rb_node rb_node; }; static void free_sd_tree(struct rb_node *node) { if (node) { free_sd_tree(node->rb_left); free_sd_tree(node->rb_right); FREE(container_of(node, struct sd_node, rb_node)); } } /* Frees a security descriptor index set. */ void destroy_sd_set(struct sd_set *sd_set) { free_sd_tree(sd_set->rb_root.rb_node); } /* Inserts a a new node into the security descriptor index tree. */ static void insert_sd_node(struct sd_set *set, struct sd_node *new) { struct rb_root *root = &set->rb_root; struct rb_node **p = &(root->rb_node); struct rb_node *rb_parent = NULL; while (*p) { struct sd_node *this = container_of(*p, struct sd_node, rb_node); int cmp = hashes_cmp(new->hash, this->hash); rb_parent = *p; if (cmp < 0) p = &((*p)->rb_left); else if (cmp > 0) p = &((*p)->rb_right); else wimlib_assert(0); /* Duplicate SHA1 message digest */ } rb_link_node(&new->rb_node, rb_parent, p); rb_insert_color(&new->rb_node, root); } /* Returns the index of the security descriptor having a SHA1 message digest of * @hash. If not found, return -1. */ int lookup_sd(struct sd_set *set, const u8 hash[SHA1_HASH_SIZE]) { struct rb_node *node = set->rb_root.rb_node; while (node) { struct sd_node *sd_node = container_of(node, struct sd_node, rb_node); int cmp = hashes_cmp(hash, sd_node->hash); if (cmp < 0) node = node->rb_left; else if (cmp > 0) node = node->rb_right; else return sd_node->security_id; } return -1; } /* * 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. */ int sd_set_add_sd(struct sd_set *sd_set, const char descriptor[], size_t size) { u8 hash[SHA1_HASH_SIZE]; int security_id; struct sd_node *new; u8 **descriptors; u64 *sizes; u8 *descr_copy; struct wim_security_data *sd; sha1_buffer((const u8*)descriptor, size, hash); security_id = lookup_sd(sd_set, hash); if (security_id >= 0) /* Identical descriptor already exists */ return security_id; /* Need to add a new security descriptor */ new = MALLOC(sizeof(*new)); if (!new) goto out; descr_copy = MALLOC(size); if (!descr_copy) goto out_free_node; sd = sd_set->sd; memcpy(descr_copy, descriptor, size); new->security_id = sd->num_entries; copy_hash(new->hash, hash); 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 %d security descriptors", sd->num_entries); sd->total_length += size + sizeof(sd->sizes[0]); insert_sd_node(sd_set, new); return new->security_id; out_free_descr: FREE(descr_copy); out_free_node: FREE(new); out: return -1; } #endif /* WITH_NTFS_3G || __WIN32__ */