87810 - ssl_Time() will overflow in year 2106

Status: ASSIGNED

(NSS :: Libraries, defect, P3)

Description

[Wan-Teh Chang]

This bug report documents a limit of the ssl_Time() function.

The specification of ssl_Time() is:
/* returns an unsigned int containing the number of seconds in PR_Now() */
extern PRUint32 ssl_Time(void);

Since it uses an unsigned 32-bit integer to return the number of
seconds since 1970-01-01 00:00:00, it will overflow in year 2108
(1970 + 2 * 68).  This limit is fundamental in the *specification*
of ssl_Time().

If ssl_Time() is *implemented* using the standard C library function
time(), on POSIX systems with a signed 32-bit time_t type, it will
overflow in year 2038 (= 1970 + 68).

Remarks:

1. Having gone through the pain of Y2K certification in 1998-1999,
I feel obliged to document any known limits of our time functions.
For example, the current *implementation* of PR_Now() will also
break in year 2100 (bug 350).

2. Note that I made the distinction between specifications and
implementations.

Comment 1

[Nelson Bolyard (seldom reads bugmail)]

Marking future.  I propose that this should be fixed in the year 2095.

Comment 2

[Wan-Teh Chang]

I just wanted to add that the current implementation
of ssl_Time() (in sslnonce.c, revision 1.7) calls time()
and hence will be accurate until the year 2038.

Comment 3

[Wan-Teh Chang]

Changed the QA contact to Bishakha.