*) mod_auth_digest: Fix nonce generation. PR 54637 (49767ea4) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

CHANGES

+4 −0

Original line number	Diff line number	Diff line
		@@ -19,6 +19,10 @@ Changes with Apache 2.4.30
		*) regex: Allow to configure global/default options for regexes, like
		caseless matching or extended format. [Yann Ylavic]

		*) mod_auth_digest: Actually use the secret when generating nonces. This change
		may cause problems if used with round robin load balancers. PR 54637
		[Stefan Fritsch]

		*) mod_proxy: Allow setting options to globally defined balancer from
		ProxyPass used in VirtualHost. Balancers are now merged using the new
		merge_balancers method which merges the balancers options. [Jan Kaluza]

STATUS

+0 −9

Original line number	Diff line number	Diff line
		@@ -118,15 +118,6 @@ RELEASE SHOWSTOPPERS:
		PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
		[ start all new proposals below, under PATCHES PROPOSED. ]

		*) mod_auth_digest: Fix nonce generation. PR 54637
		trunk patch: http://svn.apache.org/r1463049
		http://svn.apache.org/r1492395
		http://svn.apache.org/r1493257
		http://svn.apache.org/r1494532
		2.4.x patch: http://people.apache.org/~jorton/mad_pr54637.diff
		+1: jorton, ylavic, minfrin



		PATCHES PROPOSED TO BACKPORT FROM TRUNK:
		[ New proposals should be added at the end of the list ]

modules/aaa/mod_auth_digest.c

+51 −190

Original line number	Diff line number	Diff line
		@@ -26,20 +26,13 @@
		* reports to the Apache bug-database, or send them directly to me
		* at ronald@innovation.ch.
		*
		* Requires either /dev/random (or equivalent) or the truerand library,
		* available for instance from
		* ftp://research.att.com/dist/mab/librand.shar
		*
		* Open Issues:
		* - qop=auth-int (when streams and trailer support available)
		* - nonce-format configurability
		* - Proxy-Authorization-Info header is set by this module, but is
		* currently ignored by mod_proxy (needs patch to mod_proxy)
		* - generating the secret takes a while (~ 8 seconds) if using the
		* truerand library
		* - The source of the secret should be run-time directive (with server
		* scope: RSRC_CONF). However, that could be tricky when trying to
		* choose truerand vs. file...
		* scope: RSRC_CONF)
		* - shared-mem not completely tested yet. Seems to work ok for me,
		* but... (definitely won't work on Windoze)
		* - Sharing a realm among multiple servers has following problems:
		@@ -52,6 +45,8 @@
		* captures a packet sent to one server and sends it to another
		* one. Should we add "AuthDigestNcCheck Strict"?
		* - expired nonces give amaya fits.
		* - MD5-sess and auth-int are not yet implemented. An incomplete
		* implementation has been removed and can be retrieved from svn history.
		*/

		#include "apr_sha1.h"
		@@ -94,7 +89,6 @@ typedef struct digest_config_struct {
		apr_array_header_t *qop_list;
		apr_sha1_ctx_t nonce_ctx;
		apr_time_t nonce_lifetime;
		const char *nonce_format;
		int check_nc;
		const char *algorithm;
		char *uri_list;
		@@ -113,6 +107,7 @@ typedef struct digest_config_struct {
		#define NONCE_LEN (int )(NONCE_TIME_LEN + NONCE_HASH_LEN)

		#define SECRET_LEN 20
		#define RETAINED_DATA_ID "mod_auth_digest"


		/* client list definitions */
		@@ -121,7 +116,6 @@ typedef struct hash_entry {
		unsigned long key; /* the key for this entry */
		struct hash_entry next; / next entry in the bucket */
		unsigned long nonce_count; /* for nonce-count checking */
		char ha1[2APR_MD5_DIGESTSIZE+1]; / for algorithm=MD5-sess */
		char last_nonce[NONCE_LEN+1]; /* for one-time nonce's */
		} client_entry;

		@@ -170,7 +164,7 @@ typedef union time_union {
		unsigned char arr[sizeof(apr_time_t)];
		} time_rec;

		static unsigned char secret[SECRET_LEN];
		static unsigned char *secret;

		/* client-list, opaque, and one-time-nonce stuff */

		@@ -228,35 +222,11 @@ static apr_status_t cleanup_tables(void *not_used)
		return APR_SUCCESS;
		}

		static apr_status_t initialize_secret(server_rec *s)
		{
		apr_status_t status;

		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01757)
		"generating secret for digest authentication ...");

		#if APR_HAS_RANDOM
		status = apr_generate_random_bytes(secret, sizeof(secret));
		#else
		#error APR random number support is missing; you probably need to install the truerand library.
		#endif

		if (status != APR_SUCCESS) {
		ap_log_error(APLOG_MARK, APLOG_CRIT, status, s, APLOGNO(01758)
		"error generating secret");
		return status;
		}

		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01759) "done");

		return APR_SUCCESS;
		}

		static void log_error_and_cleanup(char msg, apr_status_t sts, server_rec s)
		{
		ap_log_error(APLOG_MARK, APLOG_ERR, sts, s, APLOGNO(01760)
		"%s - all nonce-count checking, one-time nonces, and "
		"MD5-sess algorithm disabled", msg);
		"%s - all nonce-count checking and one-time nonces"
		"disabled", msg);

		cleanup_tables(NULL);
		}
		@@ -386,16 +356,32 @@ static int initialize_tables(server_rec s, apr_pool_t ctx)
		static int pre_init(apr_pool_t pconf, apr_pool_t plog, apr_pool_t *ptemp)
		{
		apr_status_t rv;
		void *retained;

		rv = ap_mutex_register(pconf, client_mutex_type, NULL, APR_LOCK_DEFAULT, 0);
		if (rv == APR_SUCCESS) {
		rv = ap_mutex_register(pconf, opaque_mutex_type, NULL, APR_LOCK_DEFAULT,
		0);
		}
		if (rv != APR_SUCCESS)
		return !OK;
		rv = ap_mutex_register(pconf, opaque_mutex_type, NULL, APR_LOCK_DEFAULT, 0);
		if (rv != APR_SUCCESS)
		return !OK;

		retained = ap_retained_data_get(RETAINED_DATA_ID);
		if (retained == NULL) {
		retained = ap_retained_data_create(RETAINED_DATA_ID, SECRET_LEN);
		ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, NULL, APLOGNO(01757)
		"generating secret for digest authentication");
		#if APR_HAS_RANDOM
		rv = apr_generate_random_bytes(retained, SECRET_LEN);
		#else
		#error APR random number support is missing
		#endif
		if (rv != APR_SUCCESS) {
		return rv;
		ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, APLOGNO(01758)
		"error generating secret");
		return !OK;
		}

		}
		secret = retained;
		return OK;
		}

		@@ -408,10 +394,6 @@ static int initialize_module(apr_pool_t p, apr_pool_t plog,
		if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG)
		return OK;

		if (initialize_secret(s) != APR_SUCCESS) {
		return !OK;
		}

		#if APR_HAS_SHARED_MEMORY
		/* Note: this stuff is currently fixed for the lifetime of the server,
		* i.e. even across restarts. This means that A) any shmem-size
		@@ -492,6 +474,16 @@ static void create_digest_dir_config(apr_pool_t p, char *dir)
		static const char set_realm(cmd_parms cmd, void config, const char realm)
		{
		digest_config_rec conf = (digest_config_rec ) config;
		#ifdef AP_DEBUG
		int i;

		/* check that we got random numbers */
		for (i = 0; i < SECRET_LEN; i++) {
		if (secret[i] != 0)
		break;
		}
		ap_assert(i < SECRET_LEN);
		#endif

		/* The core already handles the realm, but it's just too convenient to
		* grab it ourselves too and cache some setups. However, we need to
		@@ -505,7 +497,7 @@ static const char set_realm(cmd_parms cmd, void config, const char realm)
		* and directives outside a virtual host section)
		*/
		apr_sha1_init(&conf->nonce_ctx);
		apr_sha1_update_binary(&conf->nonce_ctx, secret, sizeof(secret));
		apr_sha1_update_binary(&conf->nonce_ctx, secret, SECRET_LEN);
		apr_sha1_update_binary(&conf->nonce_ctx, (const unsigned char *) realm,
		strlen(realm));

		@@ -599,8 +591,7 @@ static const char set_nonce_lifetime(cmd_parms cmd, void *config,
		static const char set_nonce_format(cmd_parms cmd, void *config,
		const char *fmt)
		{
		((digest_config_rec *) config)->nonce_format = fmt;
		return "AuthDigestNonceFormat is not implemented (yet)";
		return "AuthDigestNonceFormat is not implemented";
		}

		static const char set_nc_check(cmd_parms cmd, void *config, int flag)
		@@ -621,7 +612,7 @@ static const char set_algorithm(cmd_parms cmd, void config, const char alg)
		{
		if (!strcasecmp(alg, "MD5-sess")) {
		return "AuthDigestAlgorithm: ERROR: algorithm `MD5-sess' "
		"is not fully implemented";
		"is not implemented";
		}
		else if (strcasecmp(alg, "MD5")) {
		return apr_pstrcat(cmd->pool, "Invalid algorithm in AuthDigestAlgorithm: ", alg, NULL);
		@@ -1147,7 +1138,7 @@ static const char gen_nonce(apr_pool_t p, apr_time_t now, const char *opaque,
		static client_entry gen_client(const request_rec r)
		{
		unsigned long op;
		client_entry new_entry = { 0, NULL, 0, "", "" }, *entry;
		client_entry new_entry = { 0, NULL, 0, "" }, *entry;

		if (!opaque_cntr) {
		return NULL;
		@@ -1167,92 +1158,6 @@ static client_entry gen_client(const request_rec r)
		}


		/*
		* MD5-sess code.
		*
		* If you want to use algorithm=MD5-sess you must write get_userpw_hash()
		* yourself (see below). The dummy provided here just uses the hash from
		* the auth-file, i.e. it is only useful for testing client implementations
		* of MD5-sess .
		*/

		/*
		* get_userpw_hash() will be called each time a new session needs to be
		* generated and is expected to return the equivalent of
		*
		* h_urp = ap_md5(r->pool,
		* apr_pstrcat(r->pool, username, ":", ap_auth_name(r), ":", passwd))
		* ap_md5(r->pool,
		* (unsigned char *) apr_pstrcat(r->pool, h_urp, ":", resp->nonce, ":",
		* resp->cnonce, NULL));
		*
		* or put differently, it must return
		*
		* MD5(MD5(username ":" realm ":" password) ":" nonce ":" cnonce)
		*
		* If something goes wrong, the failure must be logged and NULL returned.
		*
		* You must implement this yourself, which will probably consist of code
		* contacting the password server with the necessary information (typically
		* the username, realm, nonce, and cnonce) and receiving the hash from it.
		*
		* TBD: This function should probably be in a separate source file so that
		* people need not modify mod_auth_digest.c each time they install a new
		* version of apache.
		*/
		static const char get_userpw_hash(const request_rec r,
		const digest_header_rec *resp,
		const digest_config_rec *conf)
		{
		return ap_md5(r->pool,
		(unsigned char *) apr_pstrcat(r->pool, conf->ha1, ":", resp->nonce,
		":", resp->cnonce, NULL));
		}


		/* Retrieve current session H(A1). If there is none and "generate" is
		* true then a new session for MD5-sess is generated and stored in the
		* client struct; if generate is false, or a new session could not be
		* generated then NULL is returned (in case of failure to generate the
		* failure reason will have been logged already).
		*/
		static const char get_session_HA1(const request_rec r,
		digest_header_rec *resp,
		const digest_config_rec *conf,
		int generate)
		{
		const char *ha1 = NULL;

		/* return the current sessions if there is one */
		if (resp->opaque && resp->client && resp->client->ha1[0]) {
		return resp->client->ha1;
		}
		else if (!generate) {
		return NULL;
		}

		/* generate a new session */
		if (!resp->client) {
		resp->client = gen_client(r);
		}
		if (resp->client) {
		ha1 = get_userpw_hash(r, resp, conf);
		if (ha1) {
		memcpy(resp->client->ha1, ha1, sizeof(resp->client->ha1));
		}
		}

		return ha1;
		}


		static void clear_session(const digest_header_rec *resp)
		{
		if (resp->client) {
		resp->client->ha1[0] = '\0';
		}
		}

		/*
		* Authorization challenge generation code (for WWW-Authenticate)
		*/
		@@ -1291,8 +1196,7 @@ static void note_digest_auth_failure(request_rec *r,

		if (resp->opaque == NULL) {
		/* new client */
		if ((conf->check_nc \|\| conf->nonce_lifetime == 0
		\|\| !strcasecmp(conf->algorithm, "MD5-sess"))
		if ((conf->check_nc \|\| conf->nonce_lifetime == 0)
		&& (resp->client = gen_client(r)) != NULL) {
		opaque = ltox(r->pool, resp->client->key);
		}
		@@ -1332,15 +1236,6 @@ static void note_digest_auth_failure(request_rec *r,
		memcpy(resp->client->last_nonce, nonce, NONCE_LEN+1);
		}

		/* Setup MD5-sess stuff. Note that we just clear out the session
		* info here, since we can't generate a new session until the request
		* from the client comes in with the cnonce.
		*/

		if (!strcasecmp(conf->algorithm, "MD5-sess")) {
		clear_session(resp);
		}

		/* setup domain attribute. We want to send this attribute wherever
		* possible so that the client won't send the Authorization header
		* unnecessarily (it's usually > 200 bytes!).
		@@ -1606,24 +1501,9 @@ static const char new_digest(const request_rec r,
		{
		const char ha1, ha2, *a2;

		if (resp->algorithm && !strcasecmp(resp->algorithm, "MD5-sess")) {
		ha1 = get_session_HA1(r, resp, conf, 1);
		if (!ha1) {
		return NULL;
		}
		}
		else {
		ha1 = conf->ha1;
		}

		if (resp->message_qop && !strcasecmp(resp->message_qop, "auth-int")) {
		a2 = apr_pstrcat(r->pool, resp->method, ":", resp->uri, ":",
		ap_md5(r->pool, (const unsigned char*) ""), NULL);
		/* TBD */
		}
		else {
		a2 = apr_pstrcat(r->pool, resp->method, ":", resp->uri, NULL);
		}
		ha2 = ap_md5(r->pool, (const unsigned char *)a2);

		return ap_md5(r->pool,
		@@ -1871,8 +1751,7 @@ static int authenticate_digest_user(request_rec *r)
		}

		if (resp->algorithm != NULL
		&& strcasecmp(resp->algorithm, "MD5")
		&& strcasecmp(resp->algorithm, "MD5-sess")) {
		&& strcasecmp(resp->algorithm, "MD5")) {
		ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01789)
		"unknown algorithm `%s' received: %s",
		resp->algorithm, r->uri);
		@@ -2024,27 +1903,9 @@ static int add_auth_info(request_rec *r)

		/* calculate rspauth attribute
		*/
		if (resp->algorithm && !strcasecmp(resp->algorithm, "MD5-sess")) {
		ha1 = get_session_HA1(r, resp, conf, 0);
		if (!ha1) {
		ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01795)
		"internal error: couldn't find session "
		"info for user %s", resp->username);
		return !OK;
		}
		}
		else {
		ha1 = conf->ha1;
		}

		if (resp->message_qop && !strcasecmp(resp->message_qop, "auth-int")) {
		a2 = apr_pstrcat(r->pool, ":", resp->uri, ":",
		ap_md5(r->pool,(const unsigned char *) ""), NULL);
		/* TBD */
		}
		else {
		a2 = apr_pstrcat(r->pool, ":", resp->uri, NULL);
		}
		ha2 = ap_md5(r->pool, (const unsigned char *)a2);

		resp_dig = ap_md5(r->pool,