Fix RFC 2617 ("auth-int" digest authorisation) as patched by Charles …

…Collicutt.

Source: #26 --- thanks!

auth.c

@@ -1,6 +1,7 @@
 /*	$Id$ */
 /*
- * Copyright (c) 2015--2017 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2015--2018 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2018 Charles Collicutt <charles@collicutt.co.uk>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -120,6 +121,7 @@ khttpdigest_validatehash(const struct kreq *req, const char *skey4)
 	char		 skey1[MD5_DIGEST_LENGTH * 2 + 1],
 			 skey2[MD5_DIGEST_LENGTH * 2 + 1],
 			 skey3[MD5_DIGEST_LENGTH * 2 + 1],
+	                 skeyb[MD5_DIGEST_LENGTH * 2 + 1],
 			 count[9];
 	size_t		 i;
 	const struct khttpdigest *auth;
@@ -139,9 +141,8 @@ khttpdigest_validatehash(const struct kreq *req, const char *skey4)
 	/*
 	 * MD5-sess hashes the nonce and client nonce as well as the
 	 * existing hash (user/real/pass).
-	 * Note that the existing hash is MD5_DIGEST_LENGTH * 2 as
-	 * validated by prncpl_pentry_check().
 	 */
+
 	if (KHTTPALG_MD5_SESS == auth->alg) {
 		MD5Init(&ctx);
 		MD5Updatec(&ctx, skey4, strlen(skey4));
@@ -155,20 +156,34 @@ khttpdigest_validatehash(const struct kreq *req, const char *skey4)
 	} else 
 		strlcpy(skey1, skey4, sizeof(skey1));
 
+	/* Now start the "auth" hash sequence. */
+
+	MD5Init(&ctx);
+	MD5Updatec(&ctx, kmethods[req->method],
+		strlen(kmethods[req->method]));
+	MD5Updatec(&ctx, ":", 1);
+	MD5Updatec(&ctx, auth->uri, strlen(auth->uri));
+
+	/*
+	 * If we're requesting integrity authentication ("auth-int"),
+	 * then we also bring in the hash of the message body.
+	 */
+
 	if (KHTTPQOP_AUTH_INT == auth->qop) {
 		/* This shouldn't happen... */
 		if (NULL == req->rawauth.digest)
 			return(-1);
-		memcpy(ha2, req->rawauth.digest, sizeof(ha2));
-	} else {
-		MD5Init(&ctx);
-		MD5Updatec(&ctx, kmethods[req->method], 
-			strlen(kmethods[req->method]));
+
+		for (i = 0; i < MD5_DIGEST_LENGTH; i++)
+			snprintf(&skeyb[i * 2], 3, "%02x",
+			    (unsigned char)req->rawauth.digest[i]);
+
 		MD5Updatec(&ctx, ":", 1);
-		MD5Updatec(&ctx, auth->uri, strlen(auth->uri));
-		MD5Final(ha2, &ctx);
+		MD5Updatec(&ctx, skeyb, MD5_DIGEST_LENGTH * 2);
 	}
 
+	MD5Final(ha2, &ctx);
+
 	for (i = 0; i < MD5_DIGEST_LENGTH; i++) 
 		snprintf(&skey2[i * 2], 3, "%02x", ha2[i]);
 

child.c

@@ -1342,17 +1342,16 @@ kworker_child_path(struct env *env, int fd, size_t envsz)
 }
 
 /*
- * Construct the "HA2" component of an HTTP digest hash.
+ * Construct the body hash component of an HTTP digest hash.
+ * See khttpdigest_validatehash(3) for where this is used.
  * See RFC 2617.
  * We only do this if our authorisation requires it!
  */
 static void
-kworker_child_bodymd5(struct env *env, int fd, 
-	size_t envsz, const char *b, size_t bsz, int md5)
+kworker_child_bodymd5(int fd, const char *b, size_t bsz, int md5)
 {
 	MD5_CTX		 ctx;
-	unsigned char 	 ha2[MD5_DIGEST_LENGTH];
-	const char 	*uri, *script, *method;
+	unsigned char 	 hab[MD5_DIGEST_LENGTH];
 	size_t		 sz;
 
 	if ( ! md5) {
@@ -1361,30 +1360,15 @@ kworker_child_bodymd5(struct env *env, int fd,
 		return;
 	}
 
-	uri = kworker_env(env, envsz, "PATH_INFO");
-	script = kworker_env(env, envsz, "SCRIPT_NAME");
-	method = kworker_env(env, envsz, "REQUEST_METHOD");
-
-	if (NULL == uri)
-		uri = "";
-	if (NULL == script)
-		script = "";
-	if (NULL == method)
-		method = "";
-
 	MD5Init(&ctx);
-	MD5Updatec(&ctx, method, strlen(method));
-	MD5Updatec(&ctx, ":", 1);
-	MD5Updatec(&ctx, script, strlen(script));
-	MD5Updatec(&ctx, uri, strlen(uri));
-	MD5Updatec(&ctx, ":", 1);
 	MD5Updatec(&ctx, b, bsz);
-	MD5Final(ha2, &ctx);
+	MD5Final(hab, &ctx);
 
 	/* This is a binary write! */
+
 	sz = MD5_DIGEST_LENGTH;
 	fullwrite(fd, &sz, sizeof(size_t));
-	fullwrite(fd, ha2, sz);
+	fullwrite(fd, hab, sz);
 }
 
 /*
@@ -1413,7 +1397,7 @@ kworker_child_body(struct env *env, int fd, size_t envsz,
 
 	if (0 == len) {
 		/* Remember to print our MD5 value. */
-		kworker_child_bodymd5(env, fd, envsz, "", 0, md5);
+		kworker_child_bodymd5(fd, "", 0, md5);
 		return;
 	}
 
@@ -1446,7 +1430,7 @@ kworker_child_body(struct env *env, int fd, size_t envsz,
 
 	/* If requested, print our MD5 value. */
 
-	kworker_child_bodymd5(env, fd, envsz, b, bsz, md5);
+	kworker_child_bodymd5(fd, b, bsz, md5);
 
 	if (bsz && KREQ_DEBUG_READ_BODY & debugging) {
 		fprintf(stderr, "%u: ", getpid());