calendarspec: improve overflow handling

Check if the parsed seconds value fits in an integer *after*
multiplying by USEC_PER_SEC, otherwise a large value can trigger
modulo by zero during normalization.

1 files changed, 7 insertions, 6 deletions

diff --git a/src/basic/calendarspec.c b/src/basic/calendarspec.c
index 3e249505a5..1b1acd3e0b 100644
--- a/src/basic/calendarspec.c
+++ b/src/basic/calendarspec.c
@@ -20,6 +20,7 @@
 #include <alloca.h>
 #include <ctype.h>
 #include <errno.h>
+#include <limits.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -96,7 +97,7 @@ static void normalize_chain(CalendarComponent **c) {
                  * While we're counting the chain, also normalize `stop`
                  * so the length of the range is a multiple of `repeat`
                  */
-                if (i->stop > i->start)
+                if (i->stop > i->start && i->repeat > 0)
                         i->stop -= (i->stop - i->start) % i->repeat;
 
         }
@@ -487,7 +488,7 @@ static int parse_weekdays(const char **p, CalendarSpec *c) {
         }
 }
 
-static int parse_component_decimal(const char **p, bool usec, unsigned long *res) {
+static int parse_component_decimal(const char **p, bool usec, int *res) {
         unsigned long value;
         const char *e = NULL;
         char *ee = NULL;
@@ -502,8 +503,6 @@ static int parse_component_decimal(const char **p, bool usec, unsigned long *res
                 return -errno;
         if (ee == *p)
                 return -EINVAL;
-        if ((unsigned long) (int) value != value)
-                return -ERANGE;
         e = ee;
 
         if (usec) {
@@ -530,6 +529,9 @@ static int parse_component_decimal(const char **p, bool usec, unsigned long *res
         }
 
 finish:
+        if (value > INT_MAX)
+                return -ERANGE;
+
         *p = e;
         *res = value;
 
@@ -556,9 +558,8 @@ static int const_chain(int value, CalendarComponent **c) {
 }
 
 static int prepend_component(const char **p, bool usec, CalendarComponent **c) {
-        unsigned long start, stop = -1, repeat = 0;
+        int r, start, stop = -1, repeat = 0;
         CalendarComponent *cc;
-        int r;
         const char *e;
 
         assert(p);