X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=acl.c;h=14edcf7d87c08617e175e0fff44e3c572e305160;hp=3a30bd453306cfc65c0dc0605af9e9015b88f1d6;hb=ac153fd54a0f093581ee863984070a325d5343b8;hpb=0f6df2322c12b1cc20dea08bb6c397465d4f5b46

diff --git a/acl.c b/acl.c
index 3a30bd45..14edcf7d 100644
--- a/acl.c
+++ b/acl.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -24,7 +24,6 @@ struct access_info {
 	struct list_head node;
 };
 
-
 /**
  * Return true if addr_1 matches addr_2 in the first `netmask' bits.
  */
@@ -37,7 +36,15 @@ static int v4_addr_match(uint32_t addr_1, uint32_t addr_2, uint8_t netmask)
 	return (htonl(addr_1) & mask) == (htonl(addr_2) & mask);
 }
 
-int host_in_acl(int fd, struct list_head *acl)
+/**
+ * Find out whether the peer name of a given fd belongs to an acl.
+ *
+ * \param fd File descriptor.
+ * \param acl The access control list.
+ *
+ * \return One if \a fd belongs to \a acl, zero otherwise.
+ */
+static int acl_lookup(int fd, struct list_head *acl)
 {
 	struct access_info *ai, *tmp;
 	struct sockaddr_storage ss;
@@ -59,37 +66,54 @@ no_match:
 	return 0;
 }
 
-void add_acl_entry(struct list_head *acl, struct in_addr addr,
-		int netmask)
+/**
+ * Add an entry to an access control list.
+ *
+ * \param acl The access control list.
+ * \param addr The address to add.
+ * \param netmask The netmask to use for this entry.
+ */
+static void acl_add_entry(struct list_head *acl, char *addr, int netmask)
 {
 	struct access_info *ai = para_malloc(sizeof(struct access_info));
-	ai->addr = addr;
+
+	inet_pton(AF_INET, addr, &ai->addr);
 	ai->netmask = netmask;
-	PARA_INFO_LOG("adding %s/%i to access list\n", inet_ntoa(ai->addr),
-		ai->netmask);
+	PARA_INFO_LOG("adding %s/%i to access list\n", addr, ai->netmask);
 	para_list_add(&ai->node, acl);
 }
 
-
-void del_acl_entry(struct list_head *acl, struct in_addr addr,
-		int netmask)
+/**
+ * Delete an entry from an access control list.
+ *
+ * \param acl The access control list.
+ * \param addr The address to delete.
+ * \param netmask The netmask of the entry to be removed from the list.
+ */
+static void acl_del_entry(struct list_head *acl, char *addr, int netmask)
 {
 	struct access_info *ai, *tmp;
 
 	list_for_each_entry_safe(ai, tmp, acl, node) {
-		char *nad = para_strdup(inet_ntoa(ai->addr));
-		if (!strcmp(nad, inet_ntoa(addr)) &&
+		if (!strcmp(addr, inet_ntoa(ai->addr)) &&
 				ai->netmask == netmask) {
 			PARA_NOTICE_LOG("removing %s/%i from access list\n",
-				nad, ai->netmask);
+					addr, ai->netmask);
 			list_del(&ai->node);
 			free(ai);
 		}
-		free(nad);
 	}
 }
 
-char *get_acl_contents(struct list_head *acl)
+/**
+ * Compute a string containing the contents of an acl.
+ *
+ * \param acl The access control list.
+ *
+ * \return A string containing the contents of \a acl, or \p NULL
+ * if \a acl is empty.
+ */
+char *acl_get_contents(struct list_head *acl)
 {
 	struct access_info *ai, *tmp_ai;
 	char *ret = NULL;
@@ -103,7 +127,14 @@ char *get_acl_contents(struct list_head *acl)
 	return ret;
 }
 
-void init_acl(struct list_head *acl, char * const *acl_info, int num)
+/**
+ * Initialize an access control list.
+ *
+ * \param acl The list to initialize.
+ * \param acl_info An array of strings of the form ip/netmask.
+ * \param num The number of strings in \a acl_info.
+ */
+void acl_init(struct list_head *acl, char * const *acl_info, int num)
 {
 	int i;
 
@@ -111,18 +142,17 @@ void init_acl(struct list_head *acl, char * const *acl_info, int num)
 	for (i = 0; i < num; i++) {
 		char *arg = para_strdup(acl_info[i]);
 		char *p = strchr(arg, '/');
-		struct in_addr addr;
 		int netmask;
 
 		if (!p)
 			goto err;
 		*p = '\0';
-		if (!inet_pton(AF_INET, arg, &addr))
+		if (!is_valid_ipv4_address(arg))
 			goto err;
 		netmask = atoi(++p);
 		if (netmask < 0 || netmask > 32)
 			goto err;
-		add_acl_entry(acl, addr, netmask);
+		acl_add_entry(acl, arg, netmask);
 		goto success;
 err:
 		PARA_CRIT_LOG("syntax error: %s\n", acl_info[i]);
@@ -132,3 +162,51 @@ success:
 	}
 }
 
+/**
+ * Check whether the peer name of a given fd is allowed by an acl.
+ *
+ * \param fd File descriptor.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ *
+ * \return Positive if the peer of \a fd is permitted by \a acl, \p -E_ACL_PERM
+ * otherwise.
+ */
+int acl_check_access(int fd, struct list_head *acl, int default_deny)
+{
+	int match = acl_lookup(fd, acl);
+
+	return (!match || default_deny) && (match || !default_deny)?
+		1 : -E_ACL_PERM;
+}
+
+/**
+ * Permit access for a range of IP addresses.
+ *
+ * \param addr The address to permit.
+ * \param netmask The netmask of the entry to be permitted.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ */
+void acl_allow(char *addr, int netmask,
+	       struct list_head *acl, int default_deny)
+{
+	if (default_deny)
+		acl_add_entry(acl, addr, netmask);
+	else
+		acl_del_entry(acl, addr, netmask);
+}
+
+/**
+ * Deny access for a range of IP addresses.
+ *
+ * \param addr The address to deny.
+ * \param netmask The netmask of the entry to be denied.
+ * \param acl The access control list.
+ * \param default_deny Whether \a acl is a whitelist.
+ */
+void acl_deny(char *addr, int netmask,
+	      struct list_head *acl, int default_deny)
+{
+	acl_allow(addr, netmask, acl, !default_deny);
+}