Gracefully parse iCal parameters with colons

According to RFC 5545, iCalendar content lines can have optional
parameters, which can be quoted strings containing colons (":"). Make
sure that such colons are not interpreted as delimiters marking the
start of the value string.

Also, add a test case that covers this corner case.

Reported-by: Håkan Jerning <jerning@home.se>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/ical.c

@@ -670,6 +670,21 @@ static long ical_compute_rpt_until(long start, ical_rpt_t * rpt)
 	}
 }
 
+/*
+ * Skip to the value part of an iCalendar content line.
+ */
+static char *ical_get_value(char *p)
+{
+	for (; *p != ':'; p++) {
+		if (*p == '\0')
+			return NULL;
+		if (*p == '"')
+			for (p++; *p != '"'; p++);
+	}
+
+	return p + 1;
+}
+
 /*
  * Read a recurrence rule from an iCalendar RRULE string.
  *
@@ -717,14 +732,13 @@ static ical_rpt_t *ical_read_rrule(FILE * log, char *rrulestr,
 	ical_rpt_t *rpt;
 	char *p;
 
-	p = strchr(rrulestr, ':');
+	p = ical_get_value(rrulestr);
 	if (!p) {
 		ical_log(log, ICAL_VEVENT, itemline,
 			 _("recurrence rule malformed."));
 		(*noskipped)++;
 		return NULL;
 	}
-	p++;
 
 	rpt = mem_malloc(sizeof(ical_rpt_t));
 	memset(rpt, 0, sizeof(ical_rpt_t));
@@ -807,14 +821,13 @@ ical_read_exdate(llist_t * exc, FILE * log, char *exstr,
 {
 	char *p, *q;
 
-	p = strchr(exstr, ':');
+	p = ical_get_value(exstr);
 	if (!p) {
 		ical_log(log, ICAL_VEVENT, itemline,
 			 _("recurrence exception dates malformed."));
 		(*noskipped)++;
 		return;
 	}
-	p++;
 
 	while ((q = strchr(p, ',')) != NULL) {
 		char buf[BUFSIZ];
@@ -835,14 +848,13 @@ static char *ical_read_note(char *line, unsigned *noskipped,
 {
 	char *p, *notestr, *note;
 
-	p = strchr(line, ':');
+	p = ical_get_value(line);
 	if (!p) {
 		ical_log(log, item_type, itemline,
 			 _("description malformed."));
 		(*noskipped)++;
 		return NULL;
 	}
-	p++;
 
 	notestr = ical_unformat_line(p);
 	if (notestr == NULL) {
@@ -865,11 +877,11 @@ static char *ical_read_summary(char *line)
 {
 	char *p, *summary;
 
-	p = strchr(line, ':');
+	p = ical_get_value(line);
 	if (!p)
 		return NULL;
 
-	summary = ical_unformat_line(p + 1);
+	summary = ical_unformat_line(p);
 	if (!summary)
 		return NULL;
 
@@ -970,28 +982,28 @@ ical_read_event(FILE * fdi, FILE * log, unsigned *noevents,
 		}
 
 		if (starts_with_ci(buf, "DTSTART")) {
-			p = strchr(buf, ':');
+			p = ical_get_value(buf);
 			if (!p) {
 				ical_log(log, ICAL_VEVENT, ITEMLINE,
 					 _("event start time malformed."));
 				goto cleanup;
 			}
 
-			vevent.start = ical_datetime2time_t(++p, &vevent_type);
+			vevent.start = ical_datetime2time_t(p, &vevent_type);
 			if (!vevent.start) {
 				ical_log(log, ICAL_VEVENT, ITEMLINE,
 					 _("could not retrieve event start time."));
 				goto cleanup;
 			}
 		} else if (starts_with_ci(buf, "DTEND")) {
-			p = strchr(buf, ':');
+			p = ical_get_value(buf);
 			if (!p) {
 				ical_log(log, ICAL_VEVENT, ITEMLINE,
 					 _("event end time malformed."));
 				goto cleanup;
 			}
 
-			vevent.end = ical_datetime2time_t(++p, &vevent_type);
+			vevent.end = ical_datetime2time_t(p, &vevent_type);
 			if (!vevent.end) {
 				ical_log(log, ICAL_VEVENT, ITEMLINE,
 					 _("could not retrieve event end time."));

test/Makefile.am

@@ -49,6 +49,7 @@ TESTS = \
 	ical-005.sh \
 	ical-006.sh \
 	ical-007.sh \
+	ical-008.sh \
 	next-001.sh \
 	search-001.sh \
 	bug-002.sh \

test/data/ical-008.ical

@@ -0,0 +1,12 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+BEGIN:VEVENT
+DTSTART;TZID="(UTC+01:00) Amsterdam, Berlin, Bern, Rom, Stockholm, Wien":19800101T000100
+DURATION:P1DT9H17M0S
+SUMMARY:Calibrator's
+END:VEVENT
+BEGIN:VTODO
+PRIORITY:1
+SUMMARY:Nary parabled Louvre's fleetest mered
+END:VTODO
+END:VCALENDAR

test/ical-008.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+. "${TEST_INIT:-./test-init.sh}"
+
+if [ "$1" = 'actual' ]; then
+  mkdir .calcurse || exit 1
+  cp "$DATA_DIR/conf" .calcurse || exit 1
+  "$CALCURSE" -D "$PWD/.calcurse" -i "$DATA_DIR/ical-008.ical"
+  "$CALCURSE" -D "$PWD/.calcurse" -s01/01/1980 -r2
+  "$CALCURSE" -D "$PWD/.calcurse" -t
+  rm -rf .calcurse || exit 1
+elif [ "$1" = 'expected' ]; then
+  cat <<EOD
+Import process report: 0017 lines read
+1 app / 0 events / 1 todo / 0 skipped
+01/01/80:
+ - 00:01 -> ..:..
+	Calibrator's
+
+01/02/80:
+ - ..:.. -> 09:18
+	Calibrator's
+to do:
+0. Nary parabled Louvre's fleetest mered
+EOD
+else
+  ./run-test "$0"
+fi