1 files changed, 305 insertions, 0 deletions

diff --git a/src/global/server_acl.c b/src/global/server_acl.c
new file mode 100644
index 0000000..5385a5a
--- /dev/null
+++ b/src/global/server_acl.c
@@ -0,0 +1,305 @@
+/*++
+/* NAME
+/*	server_acl 3
+/* SUMMARY
+/*	server access list
+/* SYNOPSIS
+/*	#include <server_acl.h>
+/*
+/*	void	server_acl_pre_jail_init(mynetworks, param_name)
+/*	const char *mynetworks;
+/*	const char *param_name;
+/*
+/*	SERVER_ACL *server_acl_parse(extern_acl, param_name)
+/*	const char *extern_acl;
+/*	const char *param_name;
+/*
+/*	int	server_acl_eval(client_addr, intern_acl, param_name)
+/*	const char *client_addr;
+/*	SERVER_ACL *intern_acl;
+/*	const char *param_name;
+/* DESCRIPTION
+/*	This module implements a permanent allow/denylist that
+/*	is meant to be evaluated immediately after a client connects
+/*	to a server.
+/*
+/*	server_acl_pre_jail_init() does before-chroot initialization
+/*	for the permit_mynetworks setting.
+/*
+/*	server_acl_parse() converts an access list from raw string
+/*	form to binary form. It should also be called as part of
+/*	before-chroot initialization.
+/*
+/*	server_acl_eval() evaluates an access list for the specified
+/*	client address.  The result is SERVER_ACL_ACT_PERMIT (permit),
+/*	SERVER_ACL_ACT_REJECT (reject), SERVER_ACL_ACT_DUNNO (no
+/*	decision), or SERVER_ACL_ACT_ERROR (error, unknown command
+/*	or database access error).
+/*
+/*	Arguments:
+/* .IP mynetworks
+/*	Network addresses that match "permit_mynetworks".
+/* .IP param_name
+/*	The configuration parameter name for the access list from
+/*	main.cf.  The information is used for error reporting (nested
+/*	table, unknown keyword) and to select the appropriate
+/*	behavior from parent_domain_matches_subdomains.
+/* .IP extern_acl
+/*	External access list representation.
+/* .IP intern_acl
+/*	Internal access list representation.
+/* .IP client_addr
+/*	The client IP address as printable string (without []).
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <string.h>
+
+#ifdef STRCASECMP_IN_STRINGS_H
+#include <strings.h>
+#endif
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <stringops.h>
+#include <dict.h>
+
+/* Global library. */
+
+#include <mail_params.h>
+#include <addr_match_list.h>
+#include <match_parent_style.h>
+#include <mynetworks.h>
+#include <server_acl.h>
+
+/* Application-specific. */
+
+static ADDR_MATCH_LIST *server_acl_mynetworks;
+static ADDR_MATCH_LIST *server_acl_mynetworks_host;
+
+#define STR vstring_str
+
+/* server_acl_pre_jail_init - initialize */
+
+void    server_acl_pre_jail_init(const char *mynetworks, const char *origin)
+{
+    if (server_acl_mynetworks) {
+	addr_match_list_free(server_acl_mynetworks);
+	if (server_acl_mynetworks_host)
+	    addr_match_list_free(server_acl_mynetworks_host);
+    }
+    server_acl_mynetworks =
+	addr_match_list_init(origin, MATCH_FLAG_RETURN
+			     | match_parent_style(origin), mynetworks);
+    if (warn_compat_break_mynetworks_style)
+	server_acl_mynetworks_host =
+	    addr_match_list_init(origin, MATCH_FLAG_RETURN
+				 | match_parent_style(origin), mynetworks_host());
+}
+
+/* server_acl_parse - parse access list */
+
+SERVER_ACL *server_acl_parse(const char *extern_acl, const char *origin)
+{
+    char   *saved_acl = mystrdup(extern_acl);
+    SERVER_ACL *intern_acl = argv_alloc(1);
+    char   *bp = saved_acl;
+    char   *acl;
+
+#define STREQ(x,y) (strcasecmp((x), (y)) == 0)
+#define STRNE(x,y) (strcasecmp((x), (y)) != 0)
+
+    /*
+     * Nested tables are not allowed. Tables are opened before entering the
+     * chroot jail, while access lists are evaluated after entering the
+     * chroot jail.
+     */
+    while ((acl = mystrtokq(&bp, CHARS_COMMA_SP, CHARS_BRACE)) != 0) {
+	if (strchr(acl, ':') != 0) {
+	    if (strchr(origin, ':') != 0) {
+		msg_warn("table %s: lookup result \"%s\" is not allowed"
+			 " -- ignoring remainder of access list",
+			 origin, acl);
+		argv_add(intern_acl, SERVER_ACL_NAME_DUNNO, (char *) 0);
+		break;
+	    } else {
+		if (dict_handle(acl) == 0)
+		    dict_register(acl, dict_open(acl, O_RDONLY, DICT_FLAG_LOCK
+						 | DICT_FLAG_FOLD_FIX
+						 | DICT_FLAG_UTF8_REQUEST));
+	    }
+	}
+	argv_add(intern_acl, acl, (char *) 0);
+    }
+    argv_terminate(intern_acl);
+
+    /*
+     * Cleanup.
+     */
+    myfree(saved_acl);
+    return (intern_acl);
+}
+
+/* server_acl_eval - evaluate access list */
+
+int     server_acl_eval(const char *client_addr, SERVER_ACL * intern_acl,
+			        const char *origin)
+{
+    const char *myname = "server_acl_eval";
+    char  **cpp;
+    DICT   *dict;
+    SERVER_ACL *argv;
+    const char *acl;
+    const char *dict_val;
+    int     ret;
+
+    for (cpp = intern_acl->argv; (acl = *cpp) != 0; cpp++) {
+	if (msg_verbose)
+	    msg_info("source=%s address=%s acl=%s",
+		     origin, client_addr, acl);
+	if (STREQ(acl, SERVER_ACL_NAME_REJECT)) {
+	    return (SERVER_ACL_ACT_REJECT);
+	} else if (STREQ(acl, SERVER_ACL_NAME_PERMIT)) {
+	    return (SERVER_ACL_ACT_PERMIT);
+	} else if (STREQ(acl, SERVER_ACL_NAME_WL_MYNETWORKS)) {
+	    if (addr_match_list_match(server_acl_mynetworks, client_addr)) {
+		if (warn_compat_break_mynetworks_style
+		    && !addr_match_list_match(server_acl_mynetworks_host,
+					      client_addr))
+		    msg_info("using backwards-compatible default setting "
+			     VAR_MYNETWORKS_STYLE "=%s to permit "
+			     "request from client \"%s\"",
+			     var_mynetworks_style, client_addr);
+		return (SERVER_ACL_ACT_PERMIT);
+	    }
+	    if (server_acl_mynetworks->error != 0) {
+		msg_warn("%s: %s: mynetworks lookup error -- ignoring the "
+			 "remainder of this access list", origin, acl);
+		return (SERVER_ACL_ACT_ERROR);
+	    }
+	} else if (strchr(acl, ':') != 0) {
+	    if ((dict = dict_handle(acl)) == 0)
+		msg_panic("%s: unexpected dictionary: %s", myname, acl);
+	    if ((dict_val = dict_get(dict, client_addr)) != 0) {
+		/* Fake up an ARGV to avoid lots of mallocs and frees. */
+		if (dict_val[strcspn(dict_val, ":" CHARS_COMMA_SP)] == 0) {
+		    ARGV_FAKE_BEGIN(fake_argv, dict_val);
+		    ret = server_acl_eval(client_addr, &fake_argv, acl);
+		    ARGV_FAKE_END;
+		} else {
+		    argv = server_acl_parse(dict_val, acl);
+		    ret = server_acl_eval(client_addr, argv, acl);
+		    argv_free(argv);
+		}
+		if (ret != SERVER_ACL_ACT_DUNNO)
+		    return (ret);
+	    } else if (dict->error != 0) {
+		msg_warn("%s: %s: table lookup error -- ignoring the remainder "
+			 "of this access list", origin, acl);
+		return (SERVER_ACL_ACT_ERROR);
+	    }
+	} else if (STREQ(acl, SERVER_ACL_NAME_DUNNO)) {
+	    return (SERVER_ACL_ACT_DUNNO);
+	} else {
+	    msg_warn("%s: unknown command: %s -- ignoring the remainder "
+		     "of this access list", origin, acl);
+	    return (SERVER_ACL_ACT_ERROR);
+	}
+    }
+    if (msg_verbose)
+	msg_info("source=%s address=%s - no match",
+		 origin, client_addr);
+    return (SERVER_ACL_ACT_DUNNO);
+}
+
+ /*
+  * Access lists need testing. Not only with good inputs; error cases must
+  * also be handled appropriately.
+  */
+#ifdef TEST
+#include <unistd.h>
+#include <stdlib.h>
+#include <vstring_vstream.h>
+#include <name_code.h>
+#include <split_at.h>
+    
+char   *var_server_acl = "";
+
+#define UPDATE_VAR(s,v) do { if (*(s)) myfree(s); (s) = mystrdup(v); } while (0)
+
+int     main(void)
+{
+    VSTRING *buf = vstring_alloc(100);
+    SERVER_ACL *argv;
+    int     ret;
+    int     have_tty = isatty(0);
+    char   *bufp;
+    char   *cmd;
+    char   *value;
+    const NAME_CODE acl_map[] = {
+	SERVER_ACL_NAME_ERROR, SERVER_ACL_ACT_ERROR,
+	SERVER_ACL_NAME_PERMIT, SERVER_ACL_ACT_PERMIT,
+	SERVER_ACL_NAME_REJECT, SERVER_ACL_ACT_REJECT,
+	SERVER_ACL_NAME_DUNNO, SERVER_ACL_ACT_DUNNO,
+	0,
+    };
+
+    /*
+     * No static initializer because these are owned by a library.
+     */
+    var_par_dom_match = DEF_PAR_DOM_MATCH;
+    var_mynetworks = "";
+
+#define VAR_SERVER_ACL "server_acl"
+
+    while (vstring_get_nonl(buf, VSTREAM_IN) != VSTREAM_EOF) {
+	bufp = STR(buf);
+	if (have_tty == 0) {
+	    vstream_printf("> %s\n", bufp);
+	    vstream_fflush(VSTREAM_OUT);
+	}
+	if (*bufp == '#')
+	    continue;
+	if ((cmd = mystrtok(&bufp, " =")) == 0 || STREQ(cmd, "?")) {
+	    vstream_printf("usage: %s=value|%s=value|address=value\n",
+			   VAR_MYNETWORKS, VAR_SERVER_ACL);
+	} else if ((value = mystrtok(&bufp, " =")) == 0) {
+	    vstream_printf("missing value\n");
+	} else if (STREQ(cmd, VAR_MYNETWORKS)) {
+	    UPDATE_VAR(var_mynetworks, value);
+	} else if (STREQ(cmd, VAR_SERVER_ACL)) {
+	    UPDATE_VAR(var_server_acl, value);
+	} else if (STREQ(cmd, "address")) {
+	    server_acl_pre_jail_init(var_mynetworks, VAR_MYNETWORKS);
+	    argv = server_acl_parse(var_server_acl, VAR_SERVER_ACL);
+	    ret = server_acl_eval(value, argv, VAR_SERVER_ACL);
+	    argv_free(argv);
+	    vstream_printf("%s: %s\n", value, str_name_code(acl_map, ret));
+	} else {
+	    vstream_printf("unknown command: \"%s\"\n", cmd);
+	}
+	vstream_fflush(VSTREAM_OUT);
+    }
+    vstring_free(buf);
+    exit(0);
+}
+
+#endif