Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 300 insertions, 0 deletions

diff --git a/src/util/dict_utf8.c b/src/util/dict_utf8.c
new file mode 100644
index 0000000..f1fc65a
--- /dev/null
+++ b/src/util/dict_utf8.c
@@ -0,0 +1,300 @@
+/*++
+/* NAME
+/*	dict_utf8 3
+/* SUMMARY
+/*	dictionary UTF-8 helpers
+/* SYNOPSIS
+/*	#include <dict.h>
+/*
+/*	DICT	*dict_utf8_activate(
+/*	DICT	*dict)
+/* DESCRIPTION
+/*	dict_utf8_activate() wraps a dictionary's lookup/update/delete
+/*	methods with code that enforces UTF-8 checks on keys and
+/*	values, and that logs a warning when incorrect UTF-8 is
+/*	encountered. The original dictionary handle becomes invalid.
+/*
+/*	The wrapper code enforces a policy that maximizes application
+/*	robustness (it avoids the need for new error-handling code
+/*	paths in application code).  Attempts to store non-UTF-8
+/*	keys or values are skipped while reporting a non-error
+/*	status, attempts to look up or delete non-UTF-8 keys are
+/*	skipped while reporting a non-error status, and lookup
+/*	results that contain a non-UTF-8 value are blocked while
+/*	reporting a configuration error.
+/* BUGS
+/*	dict_utf8_activate() does not nest.
+/* 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>
+
+ /*
+  * Utility library.
+  */
+#include <msg.h>
+#include <stringops.h>
+#include <dict.h>
+#include <mymalloc.h>
+#include <msg.h>
+
+ /*
+  * The goal is to maximize robustness: bad UTF-8 should not appear in keys,
+  * because those are derived from controlled inputs, and values should be
+  * printable before they are stored. But if we failed to check something
+  * then it should not result in fatal errors and thus open up the system for
+  * a denial-of-service attack.
+  * 
+  * Proposed over-all policy: skip attempts to store invalid UTF-8 lookup keys
+  * or values. Rationale: some storage may not permit malformed UTF-8. This
+  * maximizes program robustness. If we get an invalid lookup result, report
+  * a configuration error.
+  * 
+  * LOOKUP
+  * 
+  * If the key is invalid, log a warning and skip the request. Rationale: the
+  * item cannot exist.
+  * 
+  * If the lookup result is invalid, log a warning and return a configuration
+  * error.
+  * 
+  * UPDATE
+  * 
+  * If the key is invalid, then log a warning and skip the request. Rationale:
+  * the item cannot exist.
+  * 
+  * If the value is invalid, log a warning and skip the request. Rationale:
+  * storage may not permit malformed UTF-8. This maximizes program
+  * robustness.
+  * 
+  * DELETE
+  * 
+  * If the key is invalid, then skip the request. Rationale: the item cannot
+  * exist.
+  */
+
+/* dict_utf8_check_fold - casefold or validate string */
+
+static char *dict_utf8_check_fold(DICT *dict, const char *string,
+				          CONST_CHAR_STAR *err)
+{
+    int     fold_flag = (dict->flags & DICT_FLAG_FOLD_ANY);
+
+    /*
+     * Validate UTF-8 without casefolding.
+     */
+    if (!allascii(string) && valid_utf8_string(string, strlen(string)) == 0) {
+	if (err)
+	    *err = "malformed UTF-8 or invalid codepoint";
+	return (0);
+    }
+
+    /*
+     * Casefold UTF-8.
+     */
+    if (fold_flag != 0
+	&& (fold_flag & ((dict->flags & DICT_FLAG_FIXED) ?
+			 DICT_FLAG_FOLD_FIX : DICT_FLAG_FOLD_MUL))) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	return (casefold(dict->fold_buf, string));
+    }
+    return ((char *) string);
+}
+
+/* dict_utf8_check validate UTF-8 string */
+
+static int dict_utf8_check(const char *string, CONST_CHAR_STAR *err)
+{
+    if (!allascii(string) && valid_utf8_string(string, strlen(string)) == 0) {
+	if (err)
+	    *err = "malformed UTF-8 or invalid codepoint";
+	return (0);
+    }
+    return (1);
+}
+
+/* dict_utf8_lookup - UTF-8 lookup method wrapper */
+
+static const char *dict_utf8_lookup(DICT *dict, const char *key)
+{
+    DICT_UTF8_BACKUP *backup;
+    const char *utf8_err;
+    const char *fold_res;
+    const char *value;
+    int     saved_flags;
+
+    /*
+     * Validate and optionally fold the key, and if invalid skip the request.
+     */
+    if ((fold_res = dict_utf8_check_fold(dict, key, &utf8_err)) == 0) {
+	msg_warn("%s:%s: non-UTF-8 key \"%s\": %s",
+		 dict->type, dict->name, key, utf8_err);
+	dict->error = DICT_ERR_NONE;
+	return (0);
+    }
+
+    /*
+     * Proxy the request with casefolding turned off.
+     */
+    saved_flags = (dict->flags & DICT_FLAG_FOLD_ANY);
+    dict->flags &= ~DICT_FLAG_FOLD_ANY;
+    backup = dict->utf8_backup;
+    value = backup->lookup(dict, fold_res);
+    dict->flags |= saved_flags;
+
+    /*
+     * Validate the result, and if invalid fail the request.
+     */
+    if (value != 0 && dict_utf8_check(value, &utf8_err) == 0) {
+	msg_warn("%s:%s: key \"%s\": non-UTF-8 value \"%s\": %s",
+		 dict->type, dict->name, key, value, utf8_err);
+	dict->error = DICT_ERR_CONFIG;
+	return (0);
+    } else {
+	return (value);
+    }
+}
+
+/* dict_utf8_update - UTF-8 update method wrapper */
+
+static int dict_utf8_update(DICT *dict, const char *key, const char *value)
+{
+    DICT_UTF8_BACKUP *backup;
+    const char *utf8_err;
+    const char *fold_res;
+    int     saved_flags;
+    int     status;
+
+    /*
+     * Validate or fold the key, and if invalid skip the request.
+     */
+    if ((fold_res = dict_utf8_check_fold(dict, key, &utf8_err)) == 0) {
+	msg_warn("%s:%s: non-UTF-8 key \"%s\": %s",
+		 dict->type, dict->name, key, utf8_err);
+	dict->error = DICT_ERR_NONE;
+	return (DICT_STAT_SUCCESS);
+    }
+
+    /*
+     * Validate the value, and if invalid skip the request.
+     */
+    else if (dict_utf8_check(value, &utf8_err) == 0) {
+	msg_warn("%s:%s: key \"%s\": non-UTF-8 value \"%s\": %s",
+		 dict->type, dict->name, key, value, utf8_err);
+	dict->error = DICT_ERR_NONE;
+	return (DICT_STAT_SUCCESS);
+    }
+
+    /*
+     * Proxy the request with casefolding turned off.
+     */
+    else {
+	saved_flags = (dict->flags & DICT_FLAG_FOLD_ANY);
+	dict->flags &= ~DICT_FLAG_FOLD_ANY;
+	backup = dict->utf8_backup;
+	status = backup->update(dict, fold_res, value);
+	dict->flags |= saved_flags;
+	return (status);
+    }
+}
+
+/* dict_utf8_delete - UTF-8 delete method wrapper */
+
+static int dict_utf8_delete(DICT *dict, const char *key)
+{
+    DICT_UTF8_BACKUP *backup;
+    const char *utf8_err;
+    const char *fold_res;
+    int     saved_flags;
+    int     status;
+
+    /*
+     * Validate and optionally fold the key, and if invalid skip the request.
+     */
+    if ((fold_res = dict_utf8_check_fold(dict, key, &utf8_err)) == 0) {
+	msg_warn("%s:%s: non-UTF-8 key \"%s\": %s",
+		 dict->type, dict->name, key, utf8_err);
+	dict->error = DICT_ERR_NONE;
+	return (DICT_STAT_SUCCESS);
+    }
+
+    /*
+     * Proxy the request with casefolding turned off.
+     */
+    else {
+	saved_flags = (dict->flags & DICT_FLAG_FOLD_ANY);
+	dict->flags &= ~DICT_FLAG_FOLD_ANY;
+	backup = dict->utf8_backup;
+	status = backup->delete(dict, fold_res);
+	dict->flags |= saved_flags;
+	return (status);
+    }
+}
+
+/* dict_utf8_activate - wrap a legacy dict object for UTF-8 processing */
+
+DICT   *dict_utf8_activate(DICT *dict)
+{
+    const char myname[] = "dict_utf8_activate";
+    DICT_UTF8_BACKUP *backup;
+
+    /*
+     * Sanity check.
+     */
+    if (util_utf8_enable == 0)
+	msg_panic("%s: Unicode support is not available", myname);
+    if ((dict->flags & DICT_FLAG_UTF8_REQUEST) == 0)
+	msg_panic("%s: %s:%s does not request Unicode support",
+		  myname, dict->type, dict->name);
+    if ((dict->flags & DICT_FLAG_UTF8_ACTIVE) || dict->utf8_backup != 0)
+	msg_panic("%s: %s:%s Unicode support is already activated",
+		  myname, dict->type, dict->name);
+
+    /*
+     * Unlike dict_debug(3) we do not put a proxy dict object in front of the
+     * encapsulated object, because then we would have to bidirectionally
+     * propagate changes in the data members (errors, flags, jbuf, and so on)
+     * between proxy object and encapsulated object.
+     * 
+     * Instead we attach ourselves behind the encapsulated dict object, and
+     * redirect some function pointers to ourselves.
+     */
+    backup = dict->utf8_backup = (DICT_UTF8_BACKUP *) mymalloc(sizeof(*backup));
+
+    /*
+     * Interpose on the lookup/update/delete methods. It is a conscious
+     * decision not to tinker with the iterator or destructor.
+     */
+    backup->lookup = dict->lookup;
+    backup->update = dict->update;
+    backup->delete = dict->delete;
+
+    dict->lookup = dict_utf8_lookup;
+    dict->update = dict_utf8_update;
+    dict->delete = dict_utf8_delete;
+
+    /*
+     * Leave our mark. See sanity check above.
+     */
+    dict->flags |= DICT_FLAG_UTF8_ACTIVE;
+
+    return (dict);
+}