diff options
Diffstat (limited to 'libcli/security/create_descriptor.c')
| -rw-r--r-- | libcli/security/create_descriptor.c | 631 |
1 files changed, 631 insertions, 0 deletions
diff --git a/libcli/security/create_descriptor.c b/libcli/security/create_descriptor.c new file mode 100644 index 0000000..947d6c1 --- /dev/null +++ b/libcli/security/create_descriptor.c @@ -0,0 +1,631 @@ +/* + Copyright (C) Nadezhda Ivanova 2009 + + This program 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 program 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 this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +/* + * Name: create_descriptor + * + * Component: routines for calculating and creating security descriptors + * as described in MS-DTYP 2.5.3.x + * + * Description: + * + * + * Author: Nadezhda Ivanova + */ +#include "includes.h" +#include "libcli/security/security.h" +#include "librpc/gen_ndr/ndr_security.h" + +/* Todos: + * build the security token dacl as follows: + * SYSTEM: GA, OWNER: GA, LOGIN_SID:GW|GE + * Need session id information for the login SID. Probably + * the best place for this is during token creation + * + * Implement SD Invariants + * ACE sorting rules + * LDAP_SERVER_SD_FLAGS_OID control + * ADTS 7.1.3.3 needs to be clarified + */ + +/* the mapping function for generic rights for DS.(GA,GR,GW,GX) + * The mapping function is passed as an argument to the + * descriptor calculating routine and depends on the security + * manager that calls the calculating routine. + * TODO: need similar mappings for the file system and + * registry security managers in order to make this code + * generic for all security managers + */ + +uint32_t map_generic_rights_ds(uint32_t access_mask) +{ + if (access_mask & SEC_GENERIC_ALL) { + access_mask |= SEC_ADS_GENERIC_ALL; + access_mask &= ~SEC_GENERIC_ALL; + } + + if (access_mask & SEC_GENERIC_EXECUTE) { + access_mask |= SEC_ADS_GENERIC_EXECUTE; + access_mask &= ~SEC_GENERIC_EXECUTE; + } + + if (access_mask & SEC_GENERIC_WRITE) { + access_mask |= SEC_ADS_GENERIC_WRITE; + access_mask &= ~SEC_GENERIC_WRITE; + } + + if (access_mask & SEC_GENERIC_READ) { + access_mask |= SEC_ADS_GENERIC_READ; + access_mask &= ~SEC_GENERIC_READ; + } + + return access_mask; +} + +/* Not sure what this has to be, +* and it does not seem to have any influence */ +static bool object_in_list(const struct GUID *object_list, const struct GUID *object) +{ + size_t i; + + if (object_list == NULL) { + return true; + } + + if (GUID_all_zero(object)) { + return true; + } + + for (i=0; ; i++) { + if (GUID_all_zero(&object_list[i])) { + return false; + } + if (!GUID_equal(&object_list[i], object)) { + continue; + } + + return true; + } + + return false; +} + +/* returns true if the ACE gontains generic information + * that needs to be processed additionally */ + +static bool desc_ace_has_generic(const struct security_ace *ace) +{ + if (ace->access_mask & SEC_GENERIC_ALL || ace->access_mask & SEC_GENERIC_READ || + ace->access_mask & SEC_GENERIC_WRITE || ace->access_mask & SEC_GENERIC_EXECUTE) { + return true; + } + if (dom_sid_equal(&ace->trustee, &global_sid_Creator_Owner) || + dom_sid_equal(&ace->trustee, &global_sid_Creator_Group)) { + return true; + } + return false; +} + +/* creates an ace in which the generic information is expanded */ + +static void desc_expand_generic(struct security_ace *new_ace, + struct dom_sid *owner, + struct dom_sid *group) +{ + new_ace->access_mask = map_generic_rights_ds(new_ace->access_mask); + if (dom_sid_equal(&new_ace->trustee, &global_sid_Creator_Owner)) { + new_ace->trustee = *owner; + } + if (dom_sid_equal(&new_ace->trustee, &global_sid_Creator_Group)) { + new_ace->trustee = *group; + } + new_ace->flags = 0x0; +} + +static struct security_acl *calculate_inherited_from_parent(TALLOC_CTX *mem_ctx, + struct security_acl *acl, + bool is_container, + struct dom_sid *owner, + struct dom_sid *group, + struct GUID *object_list) +{ + uint32_t i; + TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx); + struct security_acl *tmp_acl = talloc_zero(mem_ctx, struct security_acl); + if (!tmp_acl) { + return NULL; + } + + if (!acl) { + return NULL; + } + + for (i=0; i < acl->num_aces; i++) { + const struct security_ace *ace = &acl->aces[i]; + const struct GUID *inherited_object = NULL; + const struct GUID *inherited_property = NULL; + struct security_ace *tmp_ace = NULL; + bool applies = false; + bool inherited_only = false; + bool expand_ace = false; + bool expand_only = false; + + if (is_container && (ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT)) { + applies = true; + } else if (!is_container && (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)) { + applies = true; + } + + if (!applies) { + /* + * If the ace doesn't apply to the + * current node, we should only keep + * it as SEC_ACE_FLAG_OBJECT_INHERIT + * on a container. We'll add + * SEC_ACE_FLAG_INHERITED_ACE + * and SEC_ACE_FLAG_INHERIT_ONLY below. + * + * Otherwise we should completely ignore it. + */ + if (!(ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)) { + continue; + } + } + + switch (ace->type) { + case SEC_ACE_TYPE_ACCESS_ALLOWED: + case SEC_ACE_TYPE_ACCESS_DENIED: + case SEC_ACE_TYPE_SYSTEM_AUDIT: + case SEC_ACE_TYPE_SYSTEM_ALARM: + case SEC_ACE_TYPE_ALLOWED_COMPOUND: + break; + + case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT: + case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT: + case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT: + case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT: + if (ace->object.object.flags & SEC_ACE_OBJECT_TYPE_PRESENT) { + inherited_property = &ace->object.object.type.type; + } + if (ace->object.object.flags & SEC_ACE_INHERITED_OBJECT_TYPE_PRESENT) { + inherited_object = &ace->object.object.inherited_type.inherited_type; + } + + if (inherited_object != NULL && !object_in_list(object_list, inherited_object)) { + /* + * An explicit object class schemaId is given, + * but doesn't belong to the current object. + */ + applies = false; + } + + break; + } + + if (ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT) { + if (!applies) { + /* + * If the ACE doesn't apply to + * the current object, we should + * ignore it as it should not be + * inherited any further + */ + continue; + } + /* + * We should only keep the expanded version + * of the ACE on the current object. + */ + expand_ace = true; + expand_only = true; + } else if (applies) { + /* + * We check if should also add + * the expanded version of the ACE + * in addition, in case we should + * expand generic access bits or + * special sids. + * + * In that case we need to + * keep the original ACE with + * SEC_ACE_FLAG_INHERIT_ONLY. + */ + expand_ace = desc_ace_has_generic(ace); + if (expand_ace) { + inherited_only = true; + } + } else { + /* + * If the ACE doesn't apply + * to the current object, + * we need to keep it with + * SEC_ACE_FLAG_INHERIT_ONLY + * in order to apply them to + * grandchildren + */ + inherited_only = true; + } + + if (expand_ace) { + tmp_acl->aces = talloc_realloc(tmp_acl, + tmp_acl->aces, + struct security_ace, + tmp_acl->num_aces+1); + if (tmp_acl->aces == NULL) { + talloc_free(tmp_ctx); + return NULL; + } + + tmp_ace = &tmp_acl->aces[tmp_acl->num_aces]; + tmp_acl->num_aces++; + + *tmp_ace = *ace; + + /* + * Expand generic access bits as well as special + * sids. + */ + desc_expand_generic(tmp_ace, owner, group); + + /* + * Expanded ACEs are marked as inherited, + * but never inherited any further to + * grandchildren. + */ + tmp_ace->flags |= SEC_ACE_FLAG_INHERITED_ACE; + tmp_ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT; + tmp_ace->flags &= ~SEC_ACE_FLAG_OBJECT_INHERIT; + tmp_ace->flags &= ~SEC_ACE_FLAG_NO_PROPAGATE_INHERIT; + + /* + * Expanded ACEs never have an explicit + * object class schemaId, so clear it + * if present. + */ + if (inherited_object != NULL) { + tmp_ace->object.object.flags &= ~SEC_ACE_INHERITED_OBJECT_TYPE_PRESENT; + } + + /* + * If the ACE had an explicit object class + * schemaId, but no attribute/propertySet + * we need to downgrate the _OBJECT variants + * to the normal ones. + */ + if (inherited_property == NULL) { + switch (tmp_ace->type) { + case SEC_ACE_TYPE_ACCESS_ALLOWED: + case SEC_ACE_TYPE_ACCESS_DENIED: + case SEC_ACE_TYPE_SYSTEM_AUDIT: + case SEC_ACE_TYPE_SYSTEM_ALARM: + case SEC_ACE_TYPE_ALLOWED_COMPOUND: + break; + case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT: + tmp_ace->type = SEC_ACE_TYPE_ACCESS_ALLOWED; + break; + case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT: + tmp_ace->type = SEC_ACE_TYPE_ACCESS_DENIED; + break; + case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT: + tmp_ace->type = SEC_ACE_TYPE_SYSTEM_ALARM; + break; + case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT: + tmp_ace->type = SEC_ACE_TYPE_SYSTEM_AUDIT; + break; + } + } + + if (expand_only) { + continue; + } + } + + tmp_acl->aces = talloc_realloc(tmp_acl, + tmp_acl->aces, + struct security_ace, + tmp_acl->num_aces+1); + if (tmp_acl->aces == NULL) { + talloc_free(tmp_ctx); + return NULL; + } + + tmp_ace = &tmp_acl->aces[tmp_acl->num_aces]; + tmp_acl->num_aces++; + + *tmp_ace = *ace; + tmp_ace->flags |= SEC_ACE_FLAG_INHERITED_ACE; + + if (inherited_only) { + tmp_ace->flags |= SEC_ACE_FLAG_INHERIT_ONLY; + } else { + tmp_ace->flags &= ~SEC_ACE_FLAG_INHERIT_ONLY; + } + + if (ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT) { + tmp_ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT; + tmp_ace->flags &= ~SEC_ACE_FLAG_OBJECT_INHERIT; + tmp_ace->flags &= ~SEC_ACE_FLAG_NO_PROPAGATE_INHERIT; + } + } + if (tmp_acl->num_aces == 0) { + return NULL; + } + if (acl) { + tmp_acl->revision = acl->revision; + } + return tmp_acl; +} + +static struct security_acl *process_user_acl(TALLOC_CTX *mem_ctx, + struct security_acl *acl, + bool is_container, + struct dom_sid *owner, + struct dom_sid *group, + struct GUID *object_list, + bool is_protected) +{ + uint32_t i; + TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx); + struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl); + struct security_acl *new_acl; + + if (!acl) + return NULL; + + if (!tmp_acl) + return NULL; + + tmp_acl->revision = acl->revision; + DBG_DEBUG("acl revision %d\n", acl->revision); + + for (i=0; i < acl->num_aces; i++){ + struct security_ace *ace = &acl->aces[i]; + /* Remove ID flags from user-provided ACEs + * if we break inheritance, ignore them otherwise */ + if (ace->flags & SEC_ACE_FLAG_INHERITED_ACE) { + if (is_protected) { + ace->flags &= ~SEC_ACE_FLAG_INHERITED_ACE; + } else { + continue; + } + } + + if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY && + !(ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT || + ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)) + continue; + + tmp_acl->aces = talloc_realloc(tmp_acl, + tmp_acl->aces, + struct security_ace, + tmp_acl->num_aces+1); + tmp_acl->aces[tmp_acl->num_aces] = *ace; + tmp_acl->num_aces++; + if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY) { + continue; + } + /* if the ACE contains CO, CG, GA, GE, GR or GW, and is inheritable + * it has to be expanded to two aces, the original as IO, + * and another one where these are translated */ + if (desc_ace_has_generic(ace)) { + if (!(ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT)) { + desc_expand_generic(&tmp_acl->aces[tmp_acl->num_aces-1], + owner, + group); + } else { + /*The original ACE becomes read only */ + tmp_acl->aces[tmp_acl->num_aces-1].flags |= SEC_ACE_FLAG_INHERIT_ONLY; + tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, + struct security_ace, + tmp_acl->num_aces+1); + /* add a new ACE with expanded generic info */ + tmp_acl->aces[tmp_acl->num_aces] = *ace; + desc_expand_generic(&tmp_acl->aces[tmp_acl->num_aces], + owner, + group); + tmp_acl->num_aces++; + } + } + } + new_acl = security_acl_dup(mem_ctx,tmp_acl); + + if (new_acl) + new_acl->revision = acl->revision; + + talloc_free(tmp_ctx); + return new_acl; +} + +static void cr_descr_log_descriptor(struct security_descriptor *sd, + const char *message, + int level) +{ + if (sd) { + DEBUG(level,("%s: %s\n", message, + ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_descriptor, + "", sd))); + } + else { + DEBUG(level,("%s: NULL\n", message)); + } +} + +#if 0 +static void cr_descr_log_acl(struct security_acl *acl, + const char *message, + int level) +{ + if (acl) { + DEBUG(level,("%s: %s\n", message, + ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_acl, + "", acl))); + } + else { + DEBUG(level,("%s: NULL\n", message)); + } +} +#endif + +static bool compute_acl(struct security_descriptor *parent_sd, + struct security_descriptor *creator_sd, + bool is_container, + uint32_t inherit_flags, + struct GUID *object_list, + uint32_t (*generic_map)(uint32_t access_mask), + struct security_token *token, + struct security_descriptor *new_sd) /* INOUT argument */ +{ + struct security_acl *user_dacl, *user_sacl, *inherited_dacl, *inherited_sacl; + int level = 10; + + if (!parent_sd || !(inherit_flags & SEC_DACL_AUTO_INHERIT)) { + inherited_dacl = NULL; + } else if (creator_sd && (creator_sd->type & SEC_DESC_DACL_PROTECTED)) { + inherited_dacl = NULL; + } else { + inherited_dacl = calculate_inherited_from_parent(new_sd, + parent_sd->dacl, + is_container, + new_sd->owner_sid, + new_sd->group_sid, + object_list); + } + + + if (!parent_sd || !(inherit_flags & SEC_SACL_AUTO_INHERIT)) { + inherited_sacl = NULL; + } else if (creator_sd && (creator_sd->type & SEC_DESC_SACL_PROTECTED)) { + inherited_sacl = NULL; + } else { + inherited_sacl = calculate_inherited_from_parent(new_sd, + parent_sd->sacl, + is_container, + new_sd->owner_sid, + new_sd->group_sid, + object_list); + } + + if (!creator_sd || (inherit_flags & SEC_DEFAULT_DESCRIPTOR)) { + user_dacl = NULL; + user_sacl = NULL; + } else { + user_dacl = process_user_acl(new_sd, + creator_sd->dacl, + is_container, + new_sd->owner_sid, + new_sd->group_sid, + object_list, + creator_sd->type & SEC_DESC_DACL_PROTECTED); + user_sacl = process_user_acl(new_sd, + creator_sd->sacl, + is_container, + new_sd->owner_sid, + new_sd->group_sid, + object_list, + creator_sd->type & SEC_DESC_SACL_PROTECTED); + } + cr_descr_log_descriptor(parent_sd, __location__"parent_sd", level); + cr_descr_log_descriptor(creator_sd,__location__ "creator_sd", level); + + new_sd->dacl = security_acl_concatenate(new_sd, user_dacl, inherited_dacl); + if (new_sd->dacl) { + new_sd->type |= SEC_DESC_DACL_PRESENT; + } + if (inherited_dacl) { + new_sd->type |= SEC_DESC_DACL_AUTO_INHERITED; + } + + new_sd->sacl = security_acl_concatenate(new_sd, user_sacl, inherited_sacl); + if (new_sd->sacl) { + new_sd->type |= SEC_DESC_SACL_PRESENT; + } + if (inherited_sacl) { + new_sd->type |= SEC_DESC_SACL_AUTO_INHERITED; + } + /* This is a hack to handle the fact that + * apprantly any AI flag provided by the user is preserved */ + if (creator_sd) + new_sd->type |= creator_sd->type; + cr_descr_log_descriptor(new_sd, __location__"final sd", level); + return true; +} + +struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx, + struct security_descriptor *parent_sd, + struct security_descriptor *creator_sd, + bool is_container, + struct GUID *object_list, + uint32_t inherit_flags, + struct security_token *token, + struct dom_sid *default_owner, /* valid only for DS, NULL for the other RSs */ + struct dom_sid *default_group, /* valid only for DS, NULL for the other RSs */ + uint32_t (*generic_map)(uint32_t access_mask)) +{ + struct security_descriptor *new_sd; + struct dom_sid *new_owner = NULL; + struct dom_sid *new_group = NULL; + + new_sd = security_descriptor_initialise(mem_ctx); + if (!new_sd) { + return NULL; + } + + if (!creator_sd || !creator_sd->owner_sid) { + if ((inherit_flags & SEC_OWNER_FROM_PARENT) && parent_sd) { + new_owner = parent_sd->owner_sid; + } else if (!default_owner) { + new_owner = &token->sids[PRIMARY_USER_SID_INDEX]; + } else { + new_owner = default_owner; + new_sd->type |= SEC_DESC_OWNER_DEFAULTED; + } + } else { + new_owner = creator_sd->owner_sid; + } + + if (!creator_sd || !creator_sd->group_sid){ + if ((inherit_flags & SEC_GROUP_FROM_PARENT) && parent_sd) { + new_group = parent_sd->group_sid; + } else if (!default_group && token->num_sids > PRIMARY_GROUP_SID_INDEX) { + new_group = &token->sids[PRIMARY_GROUP_SID_INDEX]; + } else if (!default_group) { + /* This will happen only for anonymous, which has no other groups */ + new_group = &token->sids[PRIMARY_USER_SID_INDEX]; + } else { + new_group = default_group; + new_sd->type |= SEC_DESC_GROUP_DEFAULTED; + } + } else { + new_group = creator_sd->group_sid; + } + + new_sd->owner_sid = talloc_memdup(new_sd, new_owner, sizeof(struct dom_sid)); + new_sd->group_sid = talloc_memdup(new_sd, new_group, sizeof(struct dom_sid)); + if (!new_sd->owner_sid || !new_sd->group_sid){ + talloc_free(new_sd); + return NULL; + } + + if (!compute_acl(parent_sd, creator_sd, + is_container, inherit_flags, object_list, + generic_map,token,new_sd)){ + talloc_free(new_sd); + return NULL; + } + + return new_sd; +} |