1 #include "first.h" 2 3 /* mod_authn_pam 4 * 5 * FUTURE POTENTIAL PERFORMANCE ENHANCEMENTS: 6 * - database response is not cached 7 * TODO: db response caching (for limited time) to reduce load on db 8 * (only cache successful logins to prevent cache bloat?) 9 * (or limit number of entries (size) of cache) 10 * (maybe have negative cache (limited size) of names not found in database) 11 * - database query is synchronous and blocks waiting for response 12 */ 13 14 #include <security/pam_appl.h> 15 16 #include "base.h" 17 #include "http_auth.h" 18 #include "log.h" 19 #include "plugin.h" 20 21 #include <stdlib.h> 22 #include <string.h> 23 24 typedef struct { 25 const char *service; 26 } plugin_config; 27 28 typedef struct { 29 PLUGIN_DATA; 30 plugin_config defaults; 31 plugin_config conf; 32 } plugin_data; 33 34 static handler_t mod_authn_pam_basic(request_st *r, void *p_d, const http_auth_require_t *require, const buffer *username, const char *pw); 35 36 INIT_FUNC(mod_authn_pam_init) { 37 static http_auth_backend_t http_auth_backend_pam = 38 { "pam", mod_authn_pam_basic, NULL, NULL }; 39 plugin_data *p = calloc(1, sizeof(*p)); 40 41 /* register http_auth_backend_pam */ 42 http_auth_backend_pam.p_d = p; 43 http_auth_backend_set(&http_auth_backend_pam); 44 45 return p; 46 } 47 48 static void mod_authn_pam_merge_config_cpv(plugin_config * const pconf, const config_plugin_value_t * const cpv) { 49 switch (cpv->k_id) { /* index into static config_plugin_keys_t cpk[] */ 50 case 0: /* auth.backend.pam.opts */ 51 if (cpv->vtype == T_CONFIG_LOCAL) 52 pconf->service = cpv->v.v; 53 break; 54 default:/* should not happen */ 55 return; 56 } 57 } 58 59 static void mod_authn_pam_merge_config(plugin_config * const pconf, const config_plugin_value_t *cpv) { 60 do { 61 mod_authn_pam_merge_config_cpv(pconf, cpv); 62 } while ((++cpv)->k_id != -1); 63 } 64 65 static void mod_authn_pam_patch_config(request_st * const r, plugin_data * const p) { 66 p->conf = p->defaults; /* copy small struct instead of memcpy() */ 67 /*memcpy(&p->conf, &p->defaults, sizeof(plugin_config));*/ 68 for (int i = 1, used = p->nconfig; i < used; ++i) { 69 if (config_check_cond(r, (uint32_t)p->cvlist[i].k_id)) 70 mod_authn_pam_merge_config(&p->conf, 71 p->cvlist + p->cvlist[i].v.u2[0]); 72 } 73 } 74 75 SETDEFAULTS_FUNC(mod_authn_pam_set_defaults) { 76 static const config_plugin_keys_t cpk[] = { 77 { CONST_STR_LEN("auth.backend.pam.opts"), 78 T_CONFIG_ARRAY_KVSTRING, 79 T_CONFIG_SCOPE_CONNECTION } 80 ,{ NULL, 0, 81 T_CONFIG_UNSET, 82 T_CONFIG_SCOPE_UNSET } 83 }; 84 85 plugin_data * const p = p_d; 86 if (!config_plugin_values_init(srv, p, cpk, "mod_authn_pam")) 87 return HANDLER_ERROR; 88 89 /* process and validate config directives 90 * (init i to 0 if global context; to 1 to skip empty global context) */ 91 for (int i = !p->cvlist[0].v.u2[1]; i < p->nconfig; ++i) { 92 config_plugin_value_t *cpv = p->cvlist + p->cvlist[i].v.u2[0]; 93 for (; -1 != cpv->k_id; ++cpv) { 94 switch (cpv->k_id) { 95 case 0: /* auth.backend.pam.opts */ 96 if (cpv->v.a->used) { 97 const data_string *ds = (const data_string *) 98 array_get_element_klen(cpv->v.a,CONST_STR_LEN("service")); 99 cpv->v.v = (NULL != ds) ? ds->value.ptr : "http"; 100 cpv->vtype = T_CONFIG_LOCAL; 101 } 102 break; 103 default:/* should not happen */ 104 break; 105 } 106 } 107 } 108 109 p->defaults.service = "http"; 110 111 /* initialize p->defaults from global config context */ 112 if (p->nconfig > 0 && p->cvlist->v.u2[1]) { 113 const config_plugin_value_t *cpv = p->cvlist + p->cvlist->v.u2[0]; 114 if (-1 != cpv->k_id) 115 mod_authn_pam_merge_config(&p->defaults, cpv); 116 } 117 118 return HANDLER_GO_ON; 119 } 120 121 static int mod_authn_pam_fn_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr) { 122 const char * const pw = (char *)appdata_ptr; 123 struct pam_response * const pr = *resp = 124 (struct pam_response *)malloc(num_msg * sizeof(struct pam_response)); 125 for (int i = 0; i < num_msg; ++i) { 126 const int style = msg[i]->msg_style; 127 pr[i].resp_retcode = 0; 128 pr[i].resp = (style==PAM_PROMPT_ECHO_OFF || style==PAM_PROMPT_ECHO_ON) 129 ? strdup(pw) 130 : NULL; 131 } 132 return PAM_SUCCESS; 133 } 134 135 static handler_t mod_authn_pam_query(request_st * const r, void *p_d, const buffer * const username, const char * const realm, const char * const pw) { 136 plugin_data *p = (plugin_data *)p_d; 137 pam_handle_t *pamh = NULL; 138 struct pam_conv conv = { mod_authn_pam_fn_conv, NULL }; 139 const int flags = PAM_SILENT | PAM_DISALLOW_NULL_AUTHTOK; 140 int rc; 141 UNUSED(realm); 142 *(const char **)&conv.appdata_ptr = pw; /*(cast away const)*/ 143 144 mod_authn_pam_patch_config(r, p); 145 146 const char * const addrstr = r->con->dst_addr_buf->ptr; 147 rc = pam_start(p->conf.service, username->ptr, &conv, &pamh); 148 if (PAM_SUCCESS != rc 149 || PAM_SUCCESS !=(rc = pam_set_item(pamh, PAM_RHOST, addrstr)) 150 || PAM_SUCCESS !=(rc = pam_authenticate(pamh, flags)) 151 || PAM_SUCCESS !=(rc = pam_acct_mgmt(pamh, flags))) 152 log_error(r->conf.errh, __FILE__, __LINE__, 153 "pam: %s", pam_strerror(pamh, rc)); 154 pam_end(pamh, rc); 155 return (PAM_SUCCESS == rc) ? HANDLER_GO_ON : HANDLER_ERROR; 156 } 157 158 static handler_t mod_authn_pam_basic(request_st * const r, void *p_d, const http_auth_require_t * const require, const buffer * const username, const char * const pw) { 159 char *realm = require->realm->ptr; 160 handler_t rc = mod_authn_pam_query(r, p_d, username, realm, pw); 161 if (HANDLER_GO_ON != rc) return rc; 162 return http_auth_match_rules(require, username->ptr, NULL, NULL) 163 ? HANDLER_GO_ON /* access granted */ 164 : HANDLER_ERROR; 165 } 166 167 int mod_authn_pam_plugin_init(plugin *p); 168 int mod_authn_pam_plugin_init(plugin *p) { 169 p->version = LIGHTTPD_VERSION_ID; 170 p->name = "authn_pam"; 171 p->init = mod_authn_pam_init; 172 p->set_defaults= mod_authn_pam_set_defaults; 173 174 return 0; 175 } 176