Issue #6608: time.asctime is now checking struct tm fields its input
before passing it to the system asctime. Patch by MunSic Jeong.
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index acd3fc3..cbb05cd 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -315,6 +315,9 @@
Convert seconds since the Epoch to a time tuple expressing local time.\n\
When 'seconds' is not passed in, convert the current time instead.");
+/* Convert 9-item tuple to tm structure. Return 1 on success, set
+ * an exception and return 0 on error.
+ */
static int
gettmarg(PyObject *args, struct tm *p)
{
@@ -377,6 +380,76 @@
return 1;
}
+/* Check values of the struct tm fields before it is passed to strftime() and
+ * asctime(). Return 1 if all values are valid, otherwise set an exception
+ * and returns 0.
+ */
+static int
+checktm(struct tm* buf)
+{
+ /* Checks added to make sure strftime() and asctime() does not crash Python by
+ indexing blindly into some array for a textual representation
+ by some bad index (fixes bug #897625 and #6608).
+
+ Also support values of zero from Python code for arguments in which
+ that is out of range by forcing that value to the lowest value that
+ is valid (fixed bug #1520914).
+
+ Valid ranges based on what is allowed in struct tm:
+
+ - tm_year: [0, max(int)] (1)
+ - tm_mon: [0, 11] (2)
+ - tm_mday: [1, 31]
+ - tm_hour: [0, 23]
+ - tm_min: [0, 59]
+ - tm_sec: [0, 60]
+ - tm_wday: [0, 6] (1)
+ - tm_yday: [0, 365] (2)
+ - tm_isdst: [-max(int), max(int)]
+
+ (1) gettmarg() handles bounds-checking.
+ (2) Python's acceptable range is one greater than the range in C,
+ thus need to check against automatic decrement by gettmarg().
+ */
+ if (buf->tm_mon == -1)
+ buf->tm_mon = 0;
+ else if (buf->tm_mon < 0 || buf->tm_mon > 11) {
+ PyErr_SetString(PyExc_ValueError, "month out of range");
+ return 0;
+ }
+ if (buf->tm_mday == 0)
+ buf->tm_mday = 1;
+ else if (buf->tm_mday < 0 || buf->tm_mday > 31) {
+ PyErr_SetString(PyExc_ValueError, "day of month out of range");
+ return 0;
+ }
+ if (buf->tm_hour < 0 || buf->tm_hour > 23) {
+ PyErr_SetString(PyExc_ValueError, "hour out of range");
+ return 0;
+ }
+ if (buf->tm_min < 0 || buf->tm_min > 59) {
+ PyErr_SetString(PyExc_ValueError, "minute out of range");
+ return 0;
+ }
+ if (buf->tm_sec < 0 || buf->tm_sec > 61) {
+ PyErr_SetString(PyExc_ValueError, "seconds out of range");
+ return 0;
+ }
+ /* tm_wday does not need checking of its upper-bound since taking
+ ``% 7`` in gettmarg() automatically restricts the range. */
+ if (buf->tm_wday < 0) {
+ PyErr_SetString(PyExc_ValueError, "day of week out of range");
+ return 0;
+ }
+ if (buf->tm_yday == -1)
+ buf->tm_yday = 0;
+ else if (buf->tm_yday < 0 || buf->tm_yday > 365) {
+ PyErr_SetString(PyExc_ValueError, "day of year out of range");
+ return 0;
+ }
+ return 1;
+}
+
#ifdef HAVE_STRFTIME
#ifdef HAVE_WCSFTIME
#define time_char wchar_t
@@ -415,69 +488,10 @@
if (tup == NULL) {
time_t tt = time(NULL);
buf = *localtime(&tt);
- } else if (!gettmarg(tup, &buf))
+ }
+ else if (!gettmarg(tup, &buf) || !checktm(&buf))
return NULL;
- /* Checks added to make sure strftime() does not crash Python by
- indexing blindly into some array for a textual representation
- by some bad index (fixes bug #897625).
-
- Also support values of zero from Python code for arguments in which
- that is out of range by forcing that value to the lowest value that
- is valid (fixed bug #1520914).
-
- Valid ranges based on what is allowed in struct tm:
-
- - tm_year: [0, max(int)] (1)
- - tm_mon: [0, 11] (2)
- - tm_mday: [1, 31]
- - tm_hour: [0, 23]
- - tm_min: [0, 59]
- - tm_sec: [0, 60]
- - tm_wday: [0, 6] (1)
- - tm_yday: [0, 365] (2)
- - tm_isdst: [-max(int), max(int)]
-
- (1) gettmarg() handles bounds-checking.
- (2) Python's acceptable range is one greater than the range in C,
- thus need to check against automatic decrement by gettmarg().
- */
- if (buf.tm_mon == -1)
- buf.tm_mon = 0;
- else if (buf.tm_mon < 0 || buf.tm_mon > 11) {
- PyErr_SetString(PyExc_ValueError, "month out of range");
- return NULL;
- }
- if (buf.tm_mday == 0)
- buf.tm_mday = 1;
- else if (buf.tm_mday < 0 || buf.tm_mday > 31) {
- PyErr_SetString(PyExc_ValueError, "day of month out of range");
- return NULL;
- }
- if (buf.tm_hour < 0 || buf.tm_hour > 23) {
- PyErr_SetString(PyExc_ValueError, "hour out of range");
- return NULL;
- }
- if (buf.tm_min < 0 || buf.tm_min > 59) {
- PyErr_SetString(PyExc_ValueError, "minute out of range");
- return NULL;
- }
- if (buf.tm_sec < 0 || buf.tm_sec > 61) {
- PyErr_SetString(PyExc_ValueError, "seconds out of range");
- return NULL;
- }
- /* tm_wday does not need checking of its upper-bound since taking
- ``% 7`` in gettmarg() automatically restricts the range. */
- if (buf.tm_wday < 0) {
- PyErr_SetString(PyExc_ValueError, "day of week out of range");
- return NULL;
- }
- if (buf.tm_yday == -1)
- buf.tm_yday = 0;
- else if (buf.tm_yday < 0 || buf.tm_yday > 365) {
- PyErr_SetString(PyExc_ValueError, "day of year out of range");
- return NULL;
- }
/* Normalize tm_isdst just in case someone foolishly implements %Z
based on the assumption that tm_isdst falls within the range of
[-1, 1] */
@@ -603,7 +617,7 @@
if (tup == NULL) {
time_t tt = time(NULL);
buf = *localtime(&tt);
- } else if (!gettmarg(tup, &buf))
+ } else if (!gettmarg(tup, &buf) || !checktm(&buf))
return NULL;
p = asctime(&buf);
if (p[24] == '\n')