From: Josef 'Jeff' Sipek <jeff.sipek@open-xchange.com>
Date: Thu, 20 May 2021 15:05:37 +0000 (-0400)
Subject: lib: event filter - Return invalid chars in the lexer
X-Git-Tag: 2.3.16~99
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d386e3727f3a1797f9729ea9866619a0a43e0687;p=thirdparty%2Fdovecot%2Fcore.git

lib: event filter - Return invalid chars in the lexer

This way, we leave it up to the parser to figure out whether or not they
make sense.
---

diff --git a/src/lib/event-filter-lexer.l b/src/lib/event-filter-lexer.l
index f1d5f9b593..08af117789 100644
--- a/src/lib/event-filter-lexer.l
+++ b/src/lib/event-filter-lexer.l
@@ -74,13 +74,30 @@ static size_t event_filter_parser_input_proc(char *buf, size_t size, yyscan_t sc
 [A-Za-z0-9:.*?_-]+		{ yylval->str = t_strdup(yytext); return TOKEN; }
 [ \t\n\r]			{ /* ignore */ }
 .				{
-					char msg[160];
-
-					i_snprintf(msg, sizeof(msg),
-						   "syntax error, unexpected character '%c'",
-						   yytext[0]);
-
-					event_filter_parser_error(yyextra, msg);
+					/*
+					 * We simply return the char to the
+					 * and let the grammar error out
+					 * with a syntax error.
+					 *
+					 * Note: The cast is significant
+					 * since utf-8 bytes >=128 will
+					 * otherwise result in sign
+					 * extension and a negative int
+					 * getting returned on some
+					 * platforms (e.g., x86) which in
+					 * turn confuses the parser.  E.g.,
+					 * if:
+					 *    *yytext = '\x80'
+					 * we get:
+					 *    *yytext             -> -128
+					 *    (int) *yytext       -> -128
+					 * which is wrong.  With the
+					 * unsigned char cast, we get:
+					 *    (u.c.) *yytext      -> 128
+					 *    (int)(u.c.) *yytext -> 128
+					 * which is correct.
+					 */
+					return (unsigned char) *yytext;
 				}
 %%
 #ifdef __clang__
diff --git a/src/lib/test-event-filter-parser.c b/src/lib/test-event-filter-parser.c
index c7973d7ea5..3cfb7fe461 100644
--- a/src/lib/test-event-filter-parser.c
+++ b/src/lib/test-event-filter-parser.c
@@ -128,6 +128,9 @@ static struct test {
 } tests[] = {
 	GOOD("", ""),
 
+	/* unquoted tokens can be only [a-zA-Z0-9:.*?_-]+ */
+	BAD("abc=r\xcc\x8c", "event filter: syntax error"),
+
 	/* check that spaces and extra parens don't break anything */
 #define CHECK_REAL(sp1, key, sp2, sp3, value, sp4) \
 	GOOD(sp1 key sp2 "=" sp3 value sp4, \