[open-ils-commits] r15886 - trunk/Open-ILS/src/c-apps (scottmk)

[svn at svn.open-ils.org]

Author: scottmk
Date: 2010-03-17 16:42:33 -0400 (Wed, 17 Mar 2010)
New Revision: 15886

Modified:
   trunk/Open-ILS/src/c-apps/oils_auth.c
Log:
Tweaked oilsAuthVerifyPassword(), mostly for clarity:

1. Addad a doxygen-style comment block to document it, plus several comments
in the body of the function.

2. A slight rearrangement: get the password from the user object after getting
the seed from memcache, instead of before.  That way if the memcache call
fails we don't need to free the copy of the user object's password.

3. Moved the declaration of ret (the return code) closer to its first use.

4. Plugged a potential (albeit improbable) memory leak in the case of an
early exit.

Also: several minor tweaks to white space and comments elsewhere.

M    Open-ILS/src/c-apps/oils_auth.c


Modified: trunk/Open-ILS/src/c-apps/oils_auth.c
===================================================================
--- trunk/Open-ILS/src/c-apps/oils_auth.c	2010-03-17 20:41:09 UTC (rev 15885)
+++ trunk/Open-ILS/src/c-apps/oils_auth.c	2010-03-17 20:42:33 UTC (rev 15886)
@@ -91,7 +91,7 @@
 }
 
 /**
-	@brief Implement the init method.
+	@brief Implement the "init" method.
 	@param ctx The method context.
 	@return Zero if successful, or -1 if not.
 
@@ -189,33 +189,61 @@
 	Returns 0 otherwise
 	Returns -1 on error
 */
+/**
+	@brief Verify the password received from the client.
+	@param ctx The method context.
+	@param userObj An object from the database, representing the user.
+	@param password An obfuscated password received from the client.
+	@return 1 if the password is valid; 0 if it isn't; or -1 upon error.
+
+	(None of the so-called "passwords" used here are in plaintext.  All have been passed
+	through at least one layer of hashing to obfuscate them.)
+
+	Take the password from the user object.  Append it to the username seed from memcache,
+	as stored previously by a call to the init method.  Take an md5 hash of the result.
+	Then compare this hash to the password received from the client.
+
+	In order for the two to match, other than by dumb luck, the client had to construct
+	the password it passed in the same way.  That means it neded to know not only the
+	original password (either hashed or plaintext), but also the seed.  The latter requirement
+	means that the client process needs either to be the same process that called the init
+	method or to receive the seed from the process that did so.
+*/
 static int oilsAuthVerifyPassword( const osrfMethodContext* ctx,
 		const jsonObject* userObj, const char* uname, const char* password ) {
 
-	int ret = 0;
-	char* realPassword = oilsFMGetString( userObj, "passwd" ); /**/
-	char* seed = osrfCacheGetString( "%s%s", OILS_AUTH_CACHE_PRFX, uname ); /**/
-
+	// Get the username seed, as stored previously in memcache by the init method
+	char* seed = osrfCacheGetString( "%s%s", OILS_AUTH_CACHE_PRFX, uname );
 	if(!seed) {
-		free(realPassword);
 		return osrfAppRequestRespondException( ctx->session,
 			ctx->request, "No authentication seed found. "
 			"open-ils.auth.authenticate.init must be called first");
 	}
 
+	// Get the hashed password from the user object
+	char* realPassword = oilsFMGetString( userObj, "passwd" );
+
 	osrfLogInternal(OSRF_LOG_MARK, "oilsAuth retrieved real password: [%s]", realPassword);
-	osrfLogDebug(OSRF_LOG_MARK,  "oilsAuth retrieved seed from cache: %s", seed );
+	osrfLogDebug(OSRF_LOG_MARK, "oilsAuth retrieved seed from cache: %s", seed );
+
+	// Concatenate them and take an MD5 hash of the result
 	char* maskedPw = md5sum( "%s%s", seed, realPassword );
+
 	free(realPassword);
 	free(seed);
 
-	if(!maskedPw)
-		return -1;
+	if( !maskedPw ) {
+		// This happens only if md5sum() runs out of memory
+		free( maskedPw );
+		return -1;  // md5sum() ran out of memory
+	}
 
 	osrfLogDebug(OSRF_LOG_MARK,  "oilsAuth generated masked password %s. "
 			"Testing against provided password %s", maskedPw, password );
 
-	if( !strcmp( maskedPw, password ) ) ret = 1;
+	int ret = 0;
+	if( !strcmp( maskedPw, password ) )
+		ret = 1;
 
 	free(maskedPw);
 
@@ -401,9 +429,9 @@
 
 	const char* ws = (workstation) ? workstation : "";
 
+	if( !type )
+		 type = OILS_AUTH_STAFF;
 
-	if(!type) type = OILS_AUTH_STAFF;
-
 	if( !( (uname || barcode) && password) ) {
 		return osrfAppRequestRespondException( ctx->session, ctx->request,
 			"username/barcode and password required for method: %s", ctx->method->name );
@@ -412,6 +440,8 @@
 	oilsEvent* response = NULL;
 	jsonObject* userObj = NULL;
 
+	// Fetch a row from the actor.usr table, by username if available,
+	// or by barcode if not.
 	if(uname) {
 		userObj = oilsUtilsFetchUserByUsername( uname );
 		if( userObj && JSON_NULL == userObj->type ) {
@@ -428,10 +458,10 @@
 				uname, (barcode ? barcode : "(none)"), ws );
 		osrfAppRespondComplete( ctx, oilsEventToJSON(response) );
 		oilsEventFree(response);
-		return 0;
+		return 0;           // No such user
 	}
 
-	/* first let's see if they have the right credentials */
+	// Such a user exists.  Now see if he or she has the right credentials.
 	int passOK = -1;
 	if(uname)
 		passOK = oilsAuthVerifyPassword( ctx, userObj, uname, password );
@@ -443,7 +473,7 @@
 		return passOK;
 	}
 
-	/* first see if their account is inactive */
+	// See if the account is active
 	char* active = oilsFMGetString(userObj, "active");
 	if( !oilsUtilsIsDBTrue(active) ) {
 		if( passOK )