diff options
Diffstat (limited to 'source4/rpc_server/drsuapi/writespn.c')
| -rw-r--r-- | source4/rpc_server/drsuapi/writespn.c | 112 |
1 files changed, 111 insertions, 1 deletions
diff --git a/source4/rpc_server/drsuapi/writespn.c b/source4/rpc_server/drsuapi/writespn.c index 2e7bd762bfa..d9338f74137 100644 --- a/source4/rpc_server/drsuapi/writespn.c +++ b/source4/rpc_server/drsuapi/writespn.c @@ -25,6 +25,106 @@ #include "dsdb/samdb/samdb.h" #include "dsdb/common/util.h" #include "rpc_server/drsuapi/dcesrv_drsuapi.h" +#include "system/kerberos.h" +#include "auth/kerberos/kerberos.h" +#include "libcli/security/session.h" +#include "libcli/security/security.h" +#include "auth/session.h" + +/* + check that the SPN update should be allowed as an override + via sam_ctx_system + + This is only called if the client is not a domain controller or + administrator + */ +static bool writespn_check_spn(struct drsuapi_bind_state *b_state, + struct dcesrv_call_state *dce_call, + struct ldb_dn *dn, + const char *spn) +{ + /* + we only allow SPN updates if: + + 1) they are on the clients own account object + 2) they are of the form SERVICE/dnshostname + */ + struct dom_sid *user_sid, *sid; + TALLOC_CTX *tmp_ctx = talloc_new(dce_call); + struct ldb_result *res; + const char *attrs[] = { "objectSID", "dnsHostName", NULL }; + int ret; + krb5_context krb_ctx; + krb5_error_code kerr; + krb5_principal principal; + const char *dns_name, *dnsHostName; + + /* + get the objectSid of the DN that is being modified, and + check it matches the user_sid in their token + */ + + ret = dsdb_search_dn(b_state->sam_ctx, tmp_ctx, &res, dn, attrs, DSDB_SEARCH_ONE_ONLY); + if (ret != LDB_SUCCESS) { + talloc_free(tmp_ctx); + return false; + } + + user_sid = &dce_call->conn->auth_state.session_info->security_token->sids[PRIMARY_USER_SID_INDEX]; + sid = samdb_result_dom_sid(tmp_ctx, res->msgs[0], "objectSid"); + if (sid == NULL) { + talloc_free(tmp_ctx); + return false; + } + + dnsHostName = ldb_msg_find_attr_as_string(res->msgs[0], "dnsHostName", NULL); + if (dnsHostName == NULL) { + talloc_free(tmp_ctx); + return false; + } + + if (!dom_sid_equal(sid, user_sid)) { + talloc_free(tmp_ctx); + return false; + } + + kerr = smb_krb5_init_context_basic(tmp_ctx, dce_call->conn->dce_ctx->lp_ctx, &krb_ctx); + if (kerr != 0) { + talloc_free(tmp_ctx); + return false; + } + + ret = krb5_parse_name_flags(krb_ctx, spn, KRB5_PRINCIPAL_PARSE_NO_REALM, &principal); + if (kerr != 0) { + krb5_free_context(krb_ctx); + talloc_free(tmp_ctx); + return false; + } + + if (principal->name.name_string.len != 2) { + krb5_free_principal(krb_ctx, principal); + krb5_free_context(krb_ctx); + talloc_free(tmp_ctx); + return false; + } + + dns_name = principal->name.name_string.val[1]; + + if (strcasecmp(dns_name, dnsHostName) != 0) { + krb5_free_principal(krb_ctx, principal); + krb5_free_context(krb_ctx); + talloc_free(tmp_ctx); + return false; + } + + /* its a simple update on their own account - allow it with + * permissions override */ + krb5_free_principal(krb_ctx, principal); + krb5_free_context(krb_ctx); + talloc_free(tmp_ctx); + + return true; +} /* drsuapi_DsWriteAccountSpn @@ -34,6 +134,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL { struct drsuapi_bind_state *b_state; struct dcesrv_handle *h; + enum security_user_level level; *r->out.level_out = r->in.level; @@ -43,6 +144,8 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL r->out.res = talloc(mem_ctx, union drsuapi_DsWriteAccountSpnResult); W_ERROR_HAVE_NO_MEMORY(r->out.res); + level = security_session_user_level(dce_call->conn->auth_state.session_info, NULL); + switch (r->in.level) { case 1: { struct drsuapi_DsWriteAccountSpnRequest1 *req; @@ -51,6 +154,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL unsigned int i; int ret; unsigned spn_count=0; + bool passed_checks = true; req = &r->in.req->req1; count = req->count; @@ -68,6 +172,12 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL /* construct mods */ for (i = 0; i < count; i++) { + if (!writespn_check_spn(b_state, + dce_call, + msg->dn, + req->spn_names[i].str)) { + passed_checks = false; + } ret = samdb_msg_add_string(b_state->sam_ctx, msg, msg, "servicePrincipalName", req->spn_names[i].str); @@ -98,7 +208,7 @@ WERROR dcesrv_drsuapi_DsWriteAccountSpn(struct dcesrv_call_state *dce_call, TALL } /* Apply to database */ - ret = dsdb_modify(b_state->sam_ctx, msg, + ret = dsdb_modify(passed_checks?b_state->sam_ctx_system:b_state->sam_ctx, msg, DSDB_MODIFY_PERMISSIVE); if (ret != LDB_SUCCESS) { DEBUG(0,("Failed to modify SPNs on %s: %s\n", |