1 files changed, 27 insertions, 21 deletions

diff --git a/modules/pam_unix/support.c b/modules/pam_unix/support.c
index 41db1f04..27ca7127 100644
--- a/modules/pam_unix/support.c
+++ b/modules/pam_unix/support.c
@@ -601,6 +601,9 @@ _unix_blankpasswd (pam_handle_t *pamh, unsigned long long ctrl, const char *name
 	char *salt = NULL;
 	int daysleft;
 	int retval;
+	int blank = 0;
+	int execloop;
+	int nonexistent_check = 1;
 
 	D(("called"));
 
@@ -624,32 +627,35 @@ _unix_blankpasswd (pam_handle_t *pamh, unsigned long long ctrl, const char *name
 
 	/* UNIX passwords area */
 
-	retval = get_pwd_hash(pamh, name, &pwd, &salt);
-
-	if (retval == PAM_UNIX_RUN_HELPER) {
-		/* salt will not be set here so we can return immediately */
-		if (_unix_run_helper_binary(pamh, NULL, ctrl, name) == PAM_SUCCESS)
-			return 1;
-		else
-			return 0;
-	}
+	/*
+	 * Execute this loop twice: one checking the password hash of an existing
+	 * user and another one for a non-existing user. This way the runtimes
+	 * are equal, making it more difficult to differentiate existing from
+	 * non-existing users.
+	 */
+	for (execloop = 0; execloop < 2; ++execloop) {
+		retval = get_pwd_hash(pamh, name, &pwd, &salt);
 
-	/* Does this user have a password? */
-	if (salt == NULL) {
-		retval = 0;
-	} else {
-		if (strlen(salt) == 0)
-			retval = 1;
-		else
-			retval = 0;
+		if (retval == PAM_UNIX_RUN_HELPER) {
+			if (_unix_run_helper_binary(pamh, NULL, ctrl, name) == PAM_SUCCESS)
+				blank = nonexistent_check;
+		} else if (retval == PAM_USER_UNKNOWN) {
+			name = "root";
+			nonexistent_check = 0;
+			continue;
+		} else if (salt != NULL) {
+			if (strlen(salt) == 0)
+				blank = nonexistent_check;
+		}
+		name = "pam_unix_non_existent:";
+		/* non-existent user check will not affect the blank value */
 	}
 
 	/* tidy up */
-
 	if (salt)
 		_pam_delete(salt);
 
-	return retval;
+	return blank;
 }
 
 int _unix_verify_password(pam_handle_t * pamh, const char *name
@@ -658,7 +664,7 @@ int _unix_verify_password(pam_handle_t * pamh, const char *name
 	struct passwd *pwd = NULL;
 	char *salt = NULL;
 	char *data_name;
-	char pw[MAXPASS + 1];
+	char pw[PAM_MAX_RESP_SIZE + 1];
 	int retval;
 
 
@@ -685,7 +691,7 @@ int _unix_verify_password(pam_handle_t * pamh, const char *name
 		strcpy(data_name + sizeof(FAIL_PREFIX) - 1, name);
 	}
 
-	if (p != NULL && strlen(p) > MAXPASS) {
+	if (p != NULL && strlen(p) > PAM_MAX_RESP_SIZE) {
 		memset(pw, 0, sizeof(pw));
 		p = strncpy(pw, p, sizeof(pw) - 1);
 	}