Guard against overflow in interval_mul() and interval_div().

Commits 146604ec43 and a898b409f6 added overflow checks to
interval_mul(), but not to interval_div(), which contains almost
identical code, and so is susceptible to the same kinds of
overflows. In addition, those checks did not catch all possible
overflow conditions.

Add additional checks to the "cascade down" code in interval_mul(),
and copy all the overflow checks over to the corresponding code in
interval_div(), so that they both generate "interval out of range"
errors, rather than returning bogus results.

Given that these errors are relatively easy to hit, back-patch to all
supported branches.

Per bug #18200 from Alexander Lakhin, and subsequent investigation.

Discussion: https://postgr.es/m/18200-5ea288c7b2d504b1%40postgresql.org

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 0e50aaec5a52639dd39e0fa684b848fc5ecaa2df..6d455cdc9de615f8d49c03c6bc6c64989f5e1669 100644 (file)
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -3315,19 +3315,13 @@ interval_mul(PG_FUNCTION_ARGS)
    result = (Interval *) palloc(sizeof(Interval));
 
    result_double = span->month * factor;
-   if (isnan(result_double) ||
-       result_double > INT_MAX || result_double < INT_MIN)
-       ereport(ERROR,
-               (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-                errmsg("interval out of range")));
+   if (isnan(result_double) || !FLOAT8_FITS_IN_INT32(result_double))
+       goto out_of_range;
    result->month = (int32) result_double;
 
    result_double = span->day * factor;
-   if (isnan(result_double) ||
-       result_double > INT_MAX || result_double < INT_MIN)
-       ereport(ERROR,
-               (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-                errmsg("interval out of range")));
+   if (isnan(result_double) || !FLOAT8_FITS_IN_INT32(result_double))
+       goto out_of_range;
    result->day = (int32) result_double;
 
    /*
@@ -3361,20 +3355,30 @@ interval_mul(PG_FUNCTION_ARGS)
     */
    if (fabs(sec_remainder) >= SECS_PER_DAY)
    {
-       result->day += (int) (sec_remainder / SECS_PER_DAY);
+       if (pg_add_s32_overflow(result->day,
+                               (int) (sec_remainder / SECS_PER_DAY),
+                               &result->day))
+           goto out_of_range;
        sec_remainder -= (int) (sec_remainder / SECS_PER_DAY) * SECS_PER_DAY;
    }
 
    /* cascade units down */
-   result->day += (int32) month_remainder_days;
+   if (pg_add_s32_overflow(result->day, (int32) month_remainder_days,
+                           &result->day))
+       goto out_of_range;
    result_double = rint(span->time * factor + sec_remainder * USECS_PER_SEC);
    if (isnan(result_double) || !FLOAT8_FITS_IN_INT64(result_double))
-       ereport(ERROR,
-               (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
-                errmsg("interval out of range")));
+       goto out_of_range;
    result->time = (int64) result_double;
 
    PG_RETURN_INTERVAL_P(result);
+
+out_of_range:
+   ereport(ERROR,
+           errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+           errmsg("interval out of range"));
+
+   PG_RETURN_NULL();           /* keep compiler quiet */
 }
 
 Datum
@@ -3393,7 +3397,8 @@ interval_div(PG_FUNCTION_ARGS)
    Interval   *span = PG_GETARG_INTERVAL_P(0);
    float8      factor = PG_GETARG_FLOAT8(1);
    double      month_remainder_days,
-               sec_remainder;
+               sec_remainder,
+               result_double;
    int32       orig_month = span->month,
                orig_day = span->day;
    Interval   *result;
@@ -3405,8 +3410,15 @@ interval_div(PG_FUNCTION_ARGS)
                (errcode(ERRCODE_DIVISION_BY_ZERO),
                 errmsg("division by zero")));
 
-   result->month = (int32) (span->month / factor);
-   result->day = (int32) (span->day / factor);
+   result_double = span->month / factor;
+   if (isnan(result_double) || !FLOAT8_FITS_IN_INT32(result_double))
+       goto out_of_range;
+   result->month = (int32) result_double;
+
+   result_double = span->day / factor;
+   if (isnan(result_double) || !FLOAT8_FITS_IN_INT32(result_double))
+       goto out_of_range;
+   result->day = (int32) result_double;
 
    /*
     * Fractional months full days into days.  See comment in interval_mul().
@@ -3418,15 +3430,30 @@ interval_div(PG_FUNCTION_ARGS)
    sec_remainder = TSROUND(sec_remainder);
    if (fabs(sec_remainder) >= SECS_PER_DAY)
    {
-       result->day += (int) (sec_remainder / SECS_PER_DAY);
+       if (pg_add_s32_overflow(result->day,
+                               (int) (sec_remainder / SECS_PER_DAY),
+                               &result->day))
+           goto out_of_range;
        sec_remainder -= (int) (sec_remainder / SECS_PER_DAY) * SECS_PER_DAY;
    }
 
    /* cascade units down */
-   result->day += (int32) month_remainder_days;
-   result->time = rint(span->time / factor + sec_remainder * USECS_PER_SEC);
+   if (pg_add_s32_overflow(result->day, (int32) month_remainder_days,
+                           &result->day))
+       goto out_of_range;
+   result_double = rint(span->time / factor + sec_remainder * USECS_PER_SEC);
+   if (isnan(result_double) || !FLOAT8_FITS_IN_INT64(result_double))
+       goto out_of_range;
+   result->time = (int64) result_double;
 
    PG_RETURN_INTERVAL_P(result);
+
+out_of_range:
+   ereport(ERROR,
+           errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+           errmsg("interval out of range"));
+
+   PG_RETURN_NULL();           /* keep compiler quiet */
 }
 
 

diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index 28b71d9681784da6714c8fa3f6a37d850d7d62fa..9fc9b0f087f15dc79ce165e15514a5ebbc50289b 100644 (file)
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -388,6 +388,19 @@ SELECT * FROM INTERVAL_TBL;
  @ 5 mons 12 hours
 (10 rows)
 
+-- multiplication and division overflow test cases
+SELECT '3000000 months'::interval * 1000;
+ERROR:  interval out of range
+SELECT '3000000 months'::interval / 0.001;
+ERROR:  interval out of range
+SELECT '3000000 days'::interval * 1000;
+ERROR:  interval out of range
+SELECT '3000000 days'::interval / 0.001;
+ERROR:  interval out of range
+SELECT '1 month 2146410 days'::interval * 1000.5002;
+ERROR:  interval out of range
+SELECT '4611686018427387904 usec'::interval / 0.1;
+ERROR:  interval out of range
 -- test avg(interval), which is somewhat fragile since people have been
 -- known to change the allowed input syntax for type interval without
 -- updating pg_aggregate.agginitval

diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index 56feda1a3d85f27aba5586d852efcd0ed95b50aa..040268db0245c11f0d988b69e2310fddbd56aa03 100644 (file)
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -136,6 +136,14 @@ SET IntervalStyle to postgres_verbose;
 
 SELECT * FROM INTERVAL_TBL;
 
+-- multiplication and division overflow test cases
+SELECT '3000000 months'::interval * 1000;
+SELECT '3000000 months'::interval / 0.001;
+SELECT '3000000 days'::interval * 1000;
+SELECT '3000000 days'::interval / 0.001;
+SELECT '1 month 2146410 days'::interval * 1000.5002;
+SELECT '4611686018427387904 usec'::interval / 0.1;
+
 -- test avg(interval), which is somewhat fragile since people have been
 -- known to change the allowed input syntax for type interval without
 -- updating pg_aggregate.agginitval