X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=acl.c;h=087ea0c805c102bace697596061978b64aa22f72;hp=3a30bd453306cfc65c0dc0605af9e9015b88f1d6;hb=f8ea51cdb591ef482806563a862e1ef28c2ed89c;hpb=0f6df2322c12b1cc20dea08bb6c397465d4f5b46 diff --git a/acl.c b/acl.c index 3a30bd45..087ea0c8 100644 --- a/acl.c +++ b/acl.c @@ -1,11 +1,13 @@ /* - * Copyright (C) 2005-2008 Andre Noll + * Copyright (C) 2005-2009 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file acl.c Access control lists for paraslash senders. */ +#include + #include "para.h" #include "error.h" #include "string.h" @@ -24,7 +26,6 @@ struct access_info { struct list_head node; }; - /** * Return true if addr_1 matches addr_2 in the first `netmask' bits. */ @@ -37,7 +38,15 @@ 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 +68,58 @@ 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, unsigned netmask) { struct access_info *ai, *tmp; + struct in_addr to_delete; + + inet_pton(AF_INET, addr, &to_delete); list_for_each_entry_safe(ai, tmp, acl, node) { - char *nad = para_strdup(inet_ntoa(ai->addr)); - if (!strcmp(nad, inet_ntoa(addr)) && - ai->netmask == netmask) { + + if (v4_addr_match(to_delete.s_addr, ai->addr.s_addr, + PARA_MIN(netmask, ai->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; @@ -103,32 +133,72 @@ 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; + char addr[16]; + int mask, i; INIT_LIST_HEAD(acl); - 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)) - goto err; - netmask = atoi(++p); - if (netmask < 0 || netmask > 32) - goto err; - add_acl_entry(acl, addr, netmask); - goto success; -err: - PARA_CRIT_LOG("syntax error: %s\n", acl_info[i]); -success: - free(arg); - continue; - } + for (i = 0; i < num; i++) + if (parse_cidr(acl_info[i], addr, sizeof(addr), &mask) == NULL) + PARA_CRIT_LOG("ACL syntax error: %s, ignoring\n", + acl_info[i]); + else + acl_add_entry(acl, addr, mask); } +/** + * 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); +}