lib-smtp: server: Fix infinite loop when client disconnects in initia…

…l state
dovecot · Dec 18, 2017 · 4e4b3ae · 4e4b3ae
1 parent 60a8575
commit 4e4b3ae
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Showing 3 changed files with 9 additions and 5 deletions.
diff --git a/src/lib-smtp/smtp-command-parser.c b/src/lib-smtp/smtp-command-parser.c
@@ -362,7 +362,7 @@ static int smtp_command_parse(struct smtp_command_parser *parser)
 		i_assert(parser->input->eof);
 		if (parser->input->stream_errno == 0) {
 			if (parser->state.state == SMTP_COMMAND_PARSE_STATE_INIT)
-				return 0;
+				ret = -2;
 			smtp_command_parser_error(parser,
 				SMTP_COMMAND_PARSE_ERROR_BROKEN_COMMAND,
 				"Premature end of input");

diff --git a/src/lib-smtp/smtp-command-parser.h b/src/lib-smtp/smtp-command-parser.h
@@ -22,6 +22,9 @@ void smtp_command_parser_deinit(struct smtp_command_parser **_parser);
 void smtp_command_parser_set_stream(struct smtp_command_parser *parser,
 	struct istream *input);
 
+/* Returns 1 if a command was returned, 0 if more data is needed, -1 on error,
+   -2 if disconnected in SMTP_COMMAND_PARSE_STATE_INIT state. -2 is mainly for
+   unit tests - it can normally be treated the same as -1. */
 int smtp_command_parse_next(struct smtp_command_parser *parser,
 			    const char **cmd_name_r, const char **cmd_params_r,
 			    enum smtp_command_parse_error *error_code_r, const char **error_r);
@@ -33,6 +36,7 @@ struct istream *
 smtp_command_parse_data_with_dot(struct smtp_command_parser *parser);
 bool smtp_command_parser_pending_data(struct smtp_command_parser *parser);
 
+/* Returns the same as smtp_command_parse_next() */
 int smtp_command_parse_auth_response(struct smtp_command_parser *parser,
 			    const char **line_r, enum smtp_command_parse_error *error_code_r,
 			    const char **error_r);

diff --git a/src/lib-smtp/test-smtp-command-parser.c b/src/lib-smtp/test-smtp-command-parser.c
@@ -85,7 +85,7 @@ static void test_smtp_command_parse_valid(void)
 		while ((ret=smtp_command_parse_next(parser,
 			&cmd_name, &cmd_params, &error_code, &error)) > 0);
 
-		test_out_reason("parse success", ret == 0, error);
+		test_out_reason("parse success", ret == -2, error);
 
 		if (ret == 0) {
 			/* verify last response only */
@@ -167,7 +167,7 @@ static void test_smtp_command_parse_invalid(void)
 		while ((ret=smtp_command_parse_next(parser,
 			&cmd_name, &cmd_params, &error_code, &error)) > 0);
 		test_out_reason(t_strdup_printf("parse(\"%s\")",
-			str_sanitize(command_text, 28)), ret < 0, error);
+			str_sanitize(command_text, 28)), ret == -1, error);
 		test_out_quiet("error code",
 			error_code == test->error_code);
 
@@ -232,7 +232,7 @@ static void test_smtp_auth_response_parse_valid(void)
 		while ((ret=smtp_command_parse_auth_response(parser,
 			&line, &error_code, &error)) > 0);
 
-		test_out_reason("parse success", ret == 0, error);
+		test_out_reason("parse success", ret == -2, error);
 
 		if (ret == 0) {
 			/* verify last response only */
@@ -302,7 +302,7 @@ static void test_smtp_auth_response_parse_invalid(void)
 		while ((ret=smtp_command_parse_auth_response(parser,
 			&line, &error_code, &error)) > 0);
 		test_out_reason(t_strdup_printf("parse(\"%s\")",
-			str_sanitize(response_text, 28)), ret < 0, error);
+			str_sanitize(response_text, 28)), ret == -1, error);
 		test_out_quiet("error code",
 			error_code == test->error_code);