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ngx_http_auth_digest_module.c
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/*
* copyright (c) Erik Dubbelboer
* fork from nginx-http-auth-digest (c) samizdat drafting co.
* derived from http_auth_basic (c) igor sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_md5.h>
#include "ngx_http_auth_digest_module.h"
static void *ngx_http_auth_digest_create_loc_conf(ngx_conf_t *cf) {
ngx_http_auth_digest_loc_conf_t *conf;
conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_auth_digest_loc_conf_t));
if (conf == NULL) {
return NULL;
}
conf->timeout = NGX_CONF_UNSET_UINT;
conf->expires = NGX_CONF_UNSET_UINT;
conf->drop_time = NGX_CONF_UNSET_UINT;
conf->replays = NGX_CONF_UNSET_UINT;
conf->evasion_time = NGX_CONF_UNSET_UINT;
conf->maxtries = NGX_CONF_UNSET_UINT;
return conf;
}
static char *ngx_http_auth_digest_merge_loc_conf(ngx_conf_t *cf, void *parent,
void *child) {
ngx_http_auth_digest_loc_conf_t *prev = parent;
ngx_http_auth_digest_loc_conf_t *conf = child;
ngx_conf_merge_sec_value(conf->timeout, prev->timeout, 60);
ngx_conf_merge_sec_value(conf->expires, prev->expires, 10);
ngx_conf_merge_sec_value(conf->drop_time, prev->drop_time, 300);
ngx_conf_merge_value(conf->replays, prev->replays, 20);
ngx_conf_merge_sec_value(conf->evasion_time, prev->evasion_time, 300);
ngx_conf_merge_value(conf->maxtries, prev->maxtries, 5);
if (conf->user_file.value.len == 0) {
conf->user_file = prev->user_file;
}
if (conf->realm.value.len == 0) {
conf->realm = prev->realm;
}
return NGX_CONF_OK;
}
static ngx_int_t ngx_http_auth_digest_init(ngx_conf_t *cf) {
ngx_http_handler_pt *h;
ngx_http_core_main_conf_t *cmcf;
ngx_str_t *shm_name;
cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
if (h == NULL) {
return NGX_ERROR;
}
*h = ngx_http_auth_digest_handler;
ngx_http_auth_digest_cleanup_timer =
ngx_pcalloc(cf->pool, sizeof(ngx_event_t));
if (ngx_http_auth_digest_cleanup_timer == NULL) {
return NGX_ERROR;
}
shm_name = ngx_palloc(cf->pool, sizeof *shm_name);
shm_name->len = sizeof("auth_digest");
shm_name->data = (unsigned char *)"auth_digest";
if (ngx_http_auth_digest_shm_size == 0) {
ngx_http_auth_digest_shm_size = 4 * 256 * ngx_pagesize; // default to 4mb
}
ngx_http_auth_digest_shm_zone =
ngx_shared_memory_add(cf, shm_name, ngx_http_auth_digest_shm_size,
&ngx_http_auth_digest_module);
if (ngx_http_auth_digest_shm_zone == NULL) {
return NGX_ERROR;
}
ngx_http_auth_digest_shm_zone->init = ngx_http_auth_digest_init_shm_zone;
return NGX_OK;
}
static ngx_int_t ngx_http_auth_digest_worker_init(ngx_cycle_t *cycle) {
if (ngx_process != NGX_PROCESS_WORKER) {
return NGX_OK;
}
// create a cleanup queue big enough for the max number of tree nodes in the
// shm
ngx_http_auth_digest_cleanup_list =
ngx_array_create(cycle->pool, NGX_HTTP_AUTH_DIGEST_CLEANUP_BATCH_SIZE,
sizeof(ngx_rbtree_node_t *));
if (ngx_http_auth_digest_cleanup_list == NULL) {
ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
"Could not allocate shared memory for auth_digest");
return NGX_ERROR;
}
ngx_connection_t *dummy;
dummy = ngx_pcalloc(cycle->pool, sizeof(ngx_connection_t));
if (dummy == NULL)
return NGX_ERROR;
dummy->fd = (ngx_socket_t)-1;
dummy->data = cycle;
ngx_http_auth_digest_cleanup_timer->log = ngx_cycle->log;
ngx_http_auth_digest_cleanup_timer->data = dummy;
ngx_http_auth_digest_cleanup_timer->handler = ngx_http_auth_digest_cleanup;
ngx_add_timer(ngx_http_auth_digest_cleanup_timer,
NGX_HTTP_AUTH_DIGEST_CLEANUP_INTERVAL);
return NGX_OK;
}
static ngx_int_t ngx_http_auth_digest_handler(ngx_http_request_t *r) {
off_t offset;
ssize_t n;
ngx_fd_t fd;
ngx_int_t rc;
ngx_err_t err;
ngx_str_t user_file, passwd_line, realm;
ngx_file_t file;
ngx_uint_t i, begin, tail, idle;
ngx_http_auth_digest_loc_conf_t *alcf;
ngx_http_auth_digest_cred_t *auth_fields;
u_char buf[NGX_HTTP_AUTH_DIGEST_BUF_SIZE];
u_char line[NGX_HTTP_AUTH_DIGEST_BUF_SIZE];
u_char *p;
if (r->internal) {
return NGX_DECLINED;
}
// if digest auth is disabled for this location, bail out immediately
alcf = ngx_http_get_module_loc_conf(r, ngx_http_auth_digest_module);
if (alcf->realm.value.len == 0) {
return NGX_DECLINED;
}
if (ngx_http_complex_value(r, &alcf->realm, &realm) != NGX_OK) {
return NGX_ERROR;
}
if (realm.len == 0 || alcf->user_file.value.len == 0) {
return NGX_DECLINED;
}
if (ngx_strcmp(realm.data, "off") == 0) {
return NGX_DECLINED;
}
if (ngx_http_auth_digest_evading(r, alcf)) {
return NGX_HTTP_UNAUTHORIZED;
}
// unpack the Authorization header (if any) and verify that it contains all
// required fields. otherwise send a challenge
auth_fields = ngx_pcalloc(r->pool, sizeof(ngx_http_auth_digest_cred_t));
rc = ngx_http_auth_digest_check_credentials(r, auth_fields);
if (rc == NGX_DECLINED) {
return ngx_http_auth_digest_send_challenge(r, &realm, 0);
} else if (rc == NGX_ERROR) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
if (ngx_strncmp(realm.data, auth_fields->realm.data, ngx_min(realm.len, auth_fields->realm.len)) != 0) {
return ngx_http_auth_digest_send_challenge(r, &realm, 0);
}
// check for the existence of a passwd file and attempt to open it
if (ngx_http_complex_value(r, &alcf->user_file, &user_file) != NGX_OK) {
return NGX_ERROR;
}
fd = ngx_open_file(user_file.data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
if (fd == NGX_INVALID_FILE) {
ngx_uint_t level;
err = ngx_errno;
if (err == NGX_ENOENT) {
level = NGX_LOG_ERR;
rc = NGX_HTTP_FORBIDDEN;
} else {
level = NGX_LOG_CRIT;
rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_log_error(level, r->connection->log, err,
ngx_open_file_n " \"%s\" failed", user_file.data);
return rc;
}
ngx_memzero(&file, sizeof(ngx_file_t));
file.fd = fd;
file.name = user_file;
file.log = r->connection->log;
// step through the passwd file and find the individual lines, then pass them
// off
// to be compared against the values in the authorization header
passwd_line.data = line;
offset = begin = tail = 0;
idle = 1;
ngx_memzero(buf, NGX_HTTP_AUTH_DIGEST_BUF_SIZE);
ngx_memzero(passwd_line.data, NGX_HTTP_AUTH_DIGEST_BUF_SIZE);
while (1) {
n = ngx_read_file(&file, buf + tail, NGX_HTTP_AUTH_DIGEST_BUF_SIZE - tail,
offset);
if (n == NGX_ERROR) {
ngx_http_auth_digest_close(&file);
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
begin = 0;
for (i = 0; i < n + tail; i++) {
if (buf[i] == '\n' || buf[i] == '\r') {
if (!idle &&
i - begin >
36) { // 36 is the min length with a single-char name and realm
p = ngx_cpymem(passwd_line.data, &buf[begin], i - begin);
p[0] = '\0';
passwd_line.len = i - begin;
rc = ngx_http_auth_digest_verify_user(r, auth_fields, &passwd_line);
if (rc == NGX_HTTP_AUTH_DIGEST_USERNOTFOUND) {
rc = NGX_DECLINED;
}
if (rc != NGX_DECLINED) {
ngx_http_auth_digest_close(&file);
ngx_http_auth_digest_evasion_tracking(
r, alcf, NGX_HTTP_AUTH_DIGEST_STATUS_SUCCESS);
return rc;
}
}
idle = 1;
begin = i;
} else if (idle) {
idle = 0;
begin = i;
}
}
if (!idle) {
tail = n + tail - begin;
if (n == 0 && tail > 36) {
p = ngx_cpymem(passwd_line.data, &buf[begin], tail);
p[0] = '\0';
passwd_line.len = i - begin;
rc = ngx_http_auth_digest_verify_user(r, auth_fields, &passwd_line);
if (rc == NGX_HTTP_AUTH_DIGEST_USERNOTFOUND) {
rc = NGX_DECLINED;
}
if (rc != NGX_DECLINED) {
ngx_http_auth_digest_close(&file);
ngx_http_auth_digest_evasion_tracking(
r, alcf, NGX_HTTP_AUTH_DIGEST_STATUS_SUCCESS);
return rc;
}
} else {
ngx_memmove(buf, &buf[begin], tail);
}
}
if (n == 0) {
break;
}
offset += n;
}
ngx_http_auth_digest_close(&file);
// log only wrong username/password,
// not expired hash
int nc = ngx_hextoi(auth_fields->nc.data, auth_fields->nc.len);
if (nc == 1) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"invalid username or password for %*s",
auth_fields->username.len, auth_fields->username.data);
}
ngx_http_auth_digest_evasion_tracking(r, alcf,
NGX_HTTP_AUTH_DIGEST_STATUS_FAILURE);
// since no match was found based on the fields in the authorization header,
// send a new challenge and let the client retry
return ngx_http_auth_digest_send_challenge(r, &realm, auth_fields->stale);
}
ngx_int_t
ngx_http_auth_digest_check_credentials(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *ctx) {
if (r->headers_in.authorization == NULL) {
return NGX_DECLINED;
}
/*
token = 1*<any CHAR except CTLs or separators>
separators = "(" | ")" | "<" | ">" | "@"
| "," | ";" | ":" | "\" | <">
| "/" | "[" | "]" | "?" | "="
| "{" | "}" | SP | HT
*/
static uint32_t token_char[] = {
0x00000000, /* 0000 0000 0000 0000 0000 0000 0000 0000 */
/* ?>=< ;:98 7654 3210 /.-, +*)( '&%$ #"! */
0x03ff6cfa, /* 0000 0011 1111 1111 0110 1100 1111 1010 */
/* _^]\ [ZYX WVUT SRQP ONML KJIH GFED CBA@ */
0xc7fffffe, /* 1100 0111 1111 1111 1111 1111 1111 1110 */
/* ~}| {zyx wvut srqp onml kjih gfed cba` */
0x57ffffff, /* 0101 0111 1111 1111 1111 1111 1111 1111 */
0x00000000, /* 0000 0000 0000 0000 0000 0000 0000 0000 */
0x00000000, /* 0000 0000 0000 0000 0000 0000 0000 0000 */
0x00000000, /* 0000 0000 0000 0000 0000 0000 0000 0000 */
0x00000000, /* 0000 0000 0000 0000 0000 0000 0000 0000 */
};
uint32_t in_value;
u_char ch, *p, *last, *start = 0, *end;
ngx_str_t name, value;
ngx_int_t comma_count = 0, quoted_pair_count = 0;
name.data = 0;
name.len = 0;
value.data = 0;
value.len = 0;
enum {
sw_start = 0,
sw_scheme,
sw_scheme_end,
sw_lws_start,
sw_lws,
sw_param_name_start,
sw_param_name,
sw_param_value_start,
sw_param_value,
sw_param_quoted_value,
sw_param_end,
sw_error,
} state;
ngx_str_t encoded = r->headers_in.authorization->value;
state = sw_start;
p = encoded.data;
last = encoded.data + encoded.len;
ch = *p++;
while (p <= last) {
switch (state) {
default:
case sw_error:
return NGX_DECLINED;
/* first char */
case sw_start:
if (ch == CR || ch == LF || ch == ' ' || ch == '\t') {
ch = *p++;
} else if (token_char[ch >> 5] & (1 << (ch & 0x1f))) {
start = p - 1;
state = sw_scheme;
} else {
state = sw_error;
}
break;
case sw_scheme:
if (token_char[ch >> 5] & (1 << (ch & 0x1f))) {
ch = *p++;
} else if (ch == ' ') {
end = p - 1;
state = sw_scheme_end;
ctx->auth_scheme.data = start;
ctx->auth_scheme.len = end - start;
if (ngx_strncasecmp(ctx->auth_scheme.data, (u_char *)"Digest",
ctx->auth_scheme.len) != 0) {
state = sw_error;
}
} else {
state = sw_error;
}
break;
case sw_scheme_end:
if (ch == ' ') {
ch = *p++;
} else {
state = sw_param_name_start;
}
break;
case sw_lws_start:
comma_count = 0;
state = sw_lws;
/* fall through */
case sw_lws:
if (comma_count > 0 && (token_char[ch >> 5] & (1 << (ch & 0x1f)))) {
state = sw_param_name_start;
} else if (ch == ',') {
comma_count++;
ch = *p++;
} else if (ch == CR || ch == LF || ch == ' ' || ch == '\t') {
ch = *p++;
} else {
state = sw_error;
}
break;
case sw_param_name_start:
if (token_char[ch >> 5] & (1 << (ch & 0x1f))) {
start = p - 1;
state = sw_param_name;
ch = *p++;
} else {
state = sw_error;
}
break;
case sw_param_name:
if (token_char[ch >> 5] & (1 << (ch & 0x1f))) {
ch = *p++;
} else if (ch == '=') {
end = p - 1;
state = sw_param_value_start;
name.data = start;
name.len = end - start;
ch = *p++;
} else {
state = sw_error;
}
break;
case sw_param_value_start:
if (token_char[ch >> 5] & (1 << (ch & 0x1f))) {
start = p - 1;
state = sw_param_value;
ch = *p++;
} else if (ch == '\"') {
start = p;
quoted_pair_count = 0;
state = sw_param_quoted_value;
ch = *p++;
} else {
state = sw_error;
}
break;
case sw_param_value:
in_value = token_char[ch >> 5] & (1 << (ch & 0x1f));
if (in_value) {
ch = *p++;
}
if (!in_value || p > last) {
end = p - 1;
value.data = start;
value.len = end - start;
state = sw_param_end;
goto param_end;
}
break;
case sw_param_quoted_value:
if (ch < 0x20 || ch == 0x7f) {
state = sw_error;
} else if (ch == '\\' && *p <= 0x7f) {
quoted_pair_count++;
/* Skip the next char, even if it's a \ */
ch = *(p += 2);
} else if (ch == '\"') {
end = p - 1;
ch = *p++;
value.data = start;
value.len = end - start - quoted_pair_count;
if (quoted_pair_count > 0) {
value.data = ngx_palloc(r->pool, value.len);
u_char *d = value.data;
u_char *s = start;
for (; s < end; s++) {
ch = *s;
if (ch == '\\') {
/* Make sure to add the next character
* even if it's a \
*/
s++;
if (s < end) {
*d++ = ch;
}
continue;
}
*d++ = ch;
}
}
state = sw_param_end;
goto param_end;
} else {
ch = *p++;
}
break;
param_end:
case sw_param_end:
if (ngx_strncasecmp(name.data, (u_char *)"username", name.len) == 0) {
ctx->username = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"qop", name.len) == 0) {
ctx->qop = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"realm", name.len) == 0) {
ctx->realm = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"nonce", name.len) == 0) {
ctx->nonce = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"nc", name.len) == 0) {
ctx->nc = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"uri", name.len) == 0) {
ctx->uri = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"cnonce", name.len) ==
0) {
ctx->cnonce = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"response", name.len) ==
0) {
ctx->response = value;
} else if (ngx_strncasecmp(name.data, (u_char *)"opaque", name.len) ==
0) {
ctx->opaque = value;
}
state = sw_lws_start;
break;
}
}
if (state != sw_lws_start && state != sw_lws) {
return NGX_DECLINED;
}
// bail out if anything but the opaque field is missing from the request
// header
if (!(ctx->username.len > 0 && ctx->qop.len > 0 && ctx->realm.len > 0 &&
ctx->nonce.len > 0 && ctx->nc.len > 0 && ctx->uri.len > 0 &&
ctx->cnonce.len > 0 && ctx->response.len > 0) ||
ctx->nonce.len != 16) {
return NGX_DECLINED;
}
return NGX_OK;
}
static ngx_int_t
ngx_http_auth_digest_verify_user(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *fields,
ngx_str_t *line) {
ngx_uint_t i, from, nomatch;
enum { sw_login, sw_ha1, sw_realm } state;
state = sw_login;
from = 0;
nomatch = 0;
// step through a single line (of the passwd file), matching the username and
// realm
// character-by-character against the request's Authorization header fields
u_char *buf = line->data;
for (i = 0; i <= line->len; i++) {
u_char ch = buf[i];
switch (state) {
case sw_login:
if (ch == '#')
nomatch = 1;
if (ch == ':') {
if (fields->username.len != i)
nomatch = 1;
state = sw_realm;
from = i + 1;
} else if (i > fields->username.len || ch != fields->username.data[i]) {
nomatch = 1;
}
break;
case sw_realm:
if (ch == '#')
nomatch = 1;
if (ch == ':') {
if (fields->realm.len != i - from)
nomatch = 1;
state = sw_ha1;
from = i + 1;
} else if (ch != fields->realm.data[i - from]) {
nomatch = 1;
}
break;
case sw_ha1:
if (ch == '\0' || ch == ':' || ch == '#' || ch == CR || ch == LF) {
if (i - from != 32)
nomatch = 1;
}
break;
}
}
if (nomatch) {
return NGX_HTTP_AUTH_DIGEST_USERNOTFOUND;
}
return ngx_http_auth_digest_verify_hash(r, fields, &buf[from]);
}
static ngx_int_t
ngx_http_auth_digest_verify_hash(ngx_http_request_t *r,
ngx_http_auth_digest_cred_t *fields,
u_char *hashed_pw) {
u_char *p;
ngx_str_t http_method;
ngx_str_t HA1, HA2, ha2_key;
ngx_str_t digest, digest_key;
ngx_md5_t md5;
u_char hash[16];
// The .net Http library sends the incorrect URI as part of the Authorization
// response. Instead of the complete URI including the query parameters it
// sends only the basic URI without the query parameters. It also uses this
// value in the calculations.
// To be compatible with the .net library the following change is made to this
// module:
// - Compare the URI in the Authorization (A-URI) with the request URI (R-URI).
// - If A-URI and R-URI are identical verify is executed.
// - If A-URI and R-URI are identical up to the '?' verify is executed
// - Otherwise the check is not executed and authorization is declined
if (!((r->unparsed_uri.len == fields->uri.len) &&
(ngx_strncmp(r->unparsed_uri.data, fields->uri.data, fields->uri.len) == 0)))
{
if (!((r->unparsed_uri.len > fields->uri.len) &&
(ngx_strncmp(r->unparsed_uri.data, fields->uri.data, fields->uri.len) == 0) &&
(r->unparsed_uri.data[fields->uri.len] == '?')))
{
return NGX_DECLINED;
}
}
// the hashing scheme:
// digest:
// MD5(MD5(username:realm:password):nonce:nc:cnonce:qop:MD5(method:uri))
// ^- HA1 ^- HA2
// verify: fields->response ==
// MD5($hashed_pw:nonce:nc:cnonce:qop:MD5(method:uri))
// ha1 was precalculated and saved to the passwd file:
// md5(username:realm:password)
HA1.len = 33;
HA1.data = ngx_pcalloc(r->pool, HA1.len);
p = ngx_cpymem(HA1.data, hashed_pw, 32);
// calculate ha2: md5(method:uri)
http_method.len = r->method_name.len + 1;
http_method.data = ngx_pcalloc(r->pool, http_method.len);
if (http_method.data == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
p = ngx_cpymem(http_method.data, r->method_name.data, r->method_name.len);
ha2_key.len = http_method.len + fields->uri.len + 1;
ha2_key.data = ngx_pcalloc(r->pool, ha2_key.len);
if (ha2_key.data == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
p = ngx_cpymem(ha2_key.data, http_method.data, http_method.len - 1);
*p++ = ':';
p = ngx_cpymem(p, fields->uri.data, fields->uri.len);
HA2.len = 33;
HA2.data = ngx_pcalloc(r->pool, HA2.len);
ngx_md5_init(&md5);
ngx_md5_update(&md5, ha2_key.data, ha2_key.len - 1);
ngx_md5_final(hash, &md5);
ngx_hex_dump(HA2.data, hash, 16);
// calculate digest: md5(ha1:nonce:nc:cnonce:qop:ha2)
digest_key.len = HA1.len - 1 + fields->nonce.len + fields->nc.len +
fields->cnonce.len + fields->qop.len + HA2.len - 1 + 5 + 1;
digest_key.data = ngx_pcalloc(r->pool, digest_key.len);
if (digest_key.data == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
p = ngx_cpymem(digest_key.data, HA1.data, HA1.len - 1);
*p++ = ':';
p = ngx_cpymem(p, fields->nonce.data, fields->nonce.len);
*p++ = ':';
p = ngx_cpymem(p, fields->nc.data, fields->nc.len);
*p++ = ':';
p = ngx_cpymem(p, fields->cnonce.data, fields->cnonce.len);
*p++ = ':';
p = ngx_cpymem(p, fields->qop.data, fields->qop.len);
*p++ = ':';
p = ngx_cpymem(p, HA2.data, HA2.len - 1);
digest.len = 33;
digest.data = ngx_pcalloc(r->pool, 33);
if (digest.data == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
ngx_md5_init(&md5);
ngx_md5_update(&md5, digest_key.data, digest_key.len - 1);
ngx_md5_final(hash, &md5);
ngx_hex_dump(digest.data, hash, 16);
// compare the hash of the full digest string to the response field of the
// auth header
// and bail out if they don't match
if (fields->response.len != digest.len - 1 ||
ngx_memcmp(digest.data, fields->response.data, fields->response.len) != 0)
return NGX_DECLINED;
ngx_http_auth_digest_nonce_t nonce;
ngx_uint_t key;
ngx_http_auth_digest_node_t *found;
ngx_slab_pool_t *shpool;
ngx_http_auth_digest_loc_conf_t *alcf;
ngx_table_elt_t *info_header;
ngx_str_t hkey, hval;
shpool = (ngx_slab_pool_t *)ngx_http_auth_digest_shm_zone->shm.addr;
alcf = ngx_http_get_module_loc_conf(r, ngx_http_auth_digest_module);
nonce.rnd = ngx_hextoi(fields->nonce.data, 8);
nonce.t = ngx_hextoi(&fields->nonce.data[8], 8);
key = ngx_crc32_short((u_char *)&nonce.rnd, sizeof nonce.rnd) ^
ngx_crc32_short((u_char *)&nonce.t, sizeof(nonce.t));
int nc = ngx_hextoi(fields->nc.data, fields->nc.len);
if (nc < 0 || nc >= alcf->replays) {
fields->stale = 1;
return NGX_DECLINED;
}
// make sure nonce and nc are both valid
ngx_shmtx_lock(&shpool->mutex);
found = (ngx_http_auth_digest_node_t *)ngx_http_auth_digest_rbtree_find(
key, ngx_http_auth_digest_rbtree->root,
ngx_http_auth_digest_rbtree->sentinel);
if (found != NULL) {
if (found->expires <= ngx_time()) {
fields->stale = 1;
goto invalid;
}
if (!ngx_bitvector_test(found->nc, nc)) {
goto invalid;
}
if (ngx_bitvector_test(found->nc, 0)) {
// if this is the first use of this nonce, switch the expiration time from
// the timeout
// param to now+expires. using the 0th element of the nc vector to flag
// this...
ngx_bitvector_set(found->nc, 0);
found->expires = ngx_time() + alcf->expires;
found->drop_time = ngx_time() + alcf->drop_time;
}
// mark this nc as ‘used’ to prevent replays
ngx_bitvector_set(found->nc, nc);
// todo: if the bitvector is now ‘full’, could preemptively expire the node
// from the rbtree
// ngx_rbtree_delete(ngx_http_auth_digest_rbtree, found);
// ngx_slab_free_locked(shpool, found);
ngx_shmtx_unlock(&shpool->mutex);
// recalculate the digest with a modified HA2 value (for rspauth) and emit
// the
// Authentication-Info header
ngx_memset(ha2_key.data, 0, ha2_key.len);
p = ngx_snprintf(ha2_key.data, 1 + fields->uri.len, ":%s",
fields->uri.data);
ngx_memset(HA2.data, 0, HA2.len);
ngx_md5_init(&md5);
ngx_md5_update(&md5, ha2_key.data, 1 + fields->uri.len);
ngx_md5_final(hash, &md5);
ngx_hex_dump(HA2.data, hash, 16);
ngx_memset(digest_key.data, 0, digest_key.len);
p = ngx_cpymem(digest_key.data, HA1.data, HA1.len - 1);
*p++ = ':';
p = ngx_cpymem(p, fields->nonce.data, fields->nonce.len);
*p++ = ':';
p = ngx_cpymem(p, fields->nc.data, fields->nc.len);
*p++ = ':';
p = ngx_cpymem(p, fields->cnonce.data, fields->cnonce.len);
*p++ = ':';
p = ngx_cpymem(p, fields->qop.data, fields->qop.len);
*p++ = ':';
p = ngx_cpymem(p, HA2.data, HA2.len - 1);
ngx_md5_init(&md5);
ngx_md5_update(&md5, digest_key.data, digest_key.len - 1);
ngx_md5_final(hash, &md5);
ngx_hex_dump(digest.data, hash, 16);
ngx_str_set(&hkey, "Authentication-Info");
// sizeof() includes the null terminator, and digest.len also counts its
// null terminator
hval.len = sizeof("qop=\"auth\", rspauth=\"\", cnonce=\"\", nc=") +
fields->cnonce.len + fields->nc.len + digest.len - 2;
hval.data = ngx_pcalloc(r->pool, hval.len + 1);
if (hval.data == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
p = ngx_snprintf(hval.data, hval.len,
"qop=\"auth\", rspauth=\"%*s\", cnonce=\"%*s\", nc=%*s",
digest.len - 1, digest.data, fields->cnonce.len,
fields->cnonce.data, fields->nc.len, fields->nc.data);
info_header = ngx_list_push(&r->headers_out.headers);
if (info_header == NULL)
return NGX_HTTP_INTERNAL_SERVER_ERROR;
info_header->key = hkey;
info_header->value = hval;
info_header->hash = 1;
return NGX_OK;
} else {
// Set the stale value to 1 because the nonce value was not found in
// the digest tree, but the computation is valid.
fields->stale = 1;
invalid:
// nonce is invalid/expired or client reused an nc value. suspicious...
ngx_shmtx_unlock(&shpool->mutex);
return NGX_DECLINED;
}
}
static ngx_int_t ngx_http_auth_digest_send_challenge(ngx_http_request_t *r,
ngx_str_t *realm,
ngx_uint_t is_stale) {
ngx_str_t challenge;
u_char *p;
size_t realm_len = strnlen((const char *)realm->data, realm->len);
r->headers_out.www_authenticate = ngx_list_push(&r->headers_out.headers);
if (r->headers_out.www_authenticate == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
r->headers_out.www_authenticate->hash = 1;
ngx_str_set(&r->headers_out.www_authenticate->key, "WWW-Authenticate");
challenge.len =
sizeof("Digest algorithm=\"MD5\", qop=\"auth\", realm=\"\", nonce=\"\"") -
1 + realm_len + 16;
if (is_stale) {
challenge.len += sizeof(", stale=\"true\"") - 1;
}
challenge.data = ngx_pnalloc(r->pool, challenge.len);
if (challenge.data == NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_http_auth_digest_nonce_t nonce;
nonce = ngx_http_auth_digest_next_nonce(r);
if (nonce.t == 0 && nonce.rnd == 0) {
// oom error when allocating nonce session in rbtree
return NGX_HTTP_SERVICE_UNAVAILABLE;
}
p = ngx_cpymem(
challenge.data, "Digest algorithm=\"MD5\", qop=\"auth\", realm=\"",
sizeof("Digest algorithm=\"MD5\", qop=\"auth\", realm=\"") - 1);
p = ngx_cpymem(p, realm->data, realm_len);
p = ngx_cpymem(p, "\", nonce=\"", sizeof("\", nonce=\"") - 1);
p = ngx_sprintf(p, "%08xl%08xl", nonce.rnd, nonce.t);
if (is_stale) {
p = ngx_cpymem(p, "\", stale=\"true\"", sizeof("\", stale=\"true\""));
} else {
p = ngx_cpymem(p, "\"", sizeof("\""));
}
r->headers_out.www_authenticate->value = challenge;
return NGX_HTTP_UNAUTHORIZED;
}
static void ngx_http_auth_digest_close(ngx_file_t *file) {
if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
ngx_log_error(NGX_LOG_ALERT, file->log, ngx_errno,
ngx_close_file_n " \"%s\" failed", file->name.data);
}
}
static char *ngx_http_auth_digest_set_user_file(ngx_conf_t *cf,
ngx_command_t *cmd,
void *conf) {
ngx_http_auth_digest_loc_conf_t *alcf = conf;
ngx_str_t *value;
ngx_http_compile_complex_value_t ccv;
if (alcf->user_file.value.len) {
return "is duplicate";
}
value = cf->args->elts;
ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
ccv.cf = cf;
ccv.value = &value[1];
ccv.complex_value = &alcf->user_file;
ccv.zero = 1;
ccv.conf_prefix = 1;
if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
}
static char *ngx_http_auth_digest_set_realm(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf) {
ngx_http_auth_digest_loc_conf_t *alcf = conf;
ngx_str_t *value;
ngx_http_compile_complex_value_t ccv;
if (alcf->realm.value.len) {
return "is duplicate";
}
value = cf->args->elts;
ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
ccv.cf = cf;
ccv.value = &value[1];
ccv.complex_value = &alcf->realm;
ccv.zero = 1;
ccv.conf_prefix = 0;
ccv.root_prefix = 0;
if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
}
static char *ngx_http_auth_digest_set_shm_size(ngx_conf_t *cf,
ngx_command_t *cmd, void *conf) {
ssize_t new_shm_size;
ngx_str_t *value;
value = cf->args->elts;
new_shm_size = ngx_parse_size(&value[1]);
if (new_shm_size == NGX_ERROR) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "Invalid memory area size `%V'",
&value[1]);
return NGX_CONF_ERROR;
}
new_shm_size = ngx_align(new_shm_size, ngx_pagesize);
if (new_shm_size < 8 * (ssize_t)ngx_pagesize) {
ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
"The auth_digest_shm_size value must be at least %udKiB",
(8 * ngx_pagesize) >> 10);
new_shm_size = 8 * ngx_pagesize;
}
if (ngx_http_auth_digest_shm_size &&
ngx_http_auth_digest_shm_size != (ngx_uint_t)new_shm_size) {
ngx_conf_log_error(
NGX_LOG_WARN, cf, 0,
"Cannot change memory area size without restart, ignoring change");
} else {
ngx_http_auth_digest_shm_size = new_shm_size;
}
ngx_conf_log_error(NGX_LOG_DEBUG, cf, 0,
"Using %udKiB of shared memory for auth_digest",
new_shm_size >> 10);
return NGX_CONF_OK;
}