Add overflow checks to money type input function

The money type input function did not have any overflow checks at all.
There were some regression tests that purported to check for overflow,
but they actually checked for the overflow behavior of the int8 type
before casting to money.  Remove those unnecessary checks and add some
that actually check the money input function.

Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>

1 files changed, 49 insertions, 4 deletions

diff --git a/src/backend/utils/adt/cash.c b/src/backend/utils/adt/cash.c
index b336185df7e..a146b0a0bc8 100644
--- a/src/backend/utils/adt/cash.c
+++ b/src/backend/utils/adt/cash.c
@@ -189,13 +189,30 @@ cash_in(PG_FUNCTION_ARGS)
 	printf("cashin- string is '%s'\n", s);
 #endif
 
+	/*
+	 * We accumulate the absolute amount in "value" and then apply the sign at
+	 * the end.  (The sign can appear before or after the digits, so it would
+	 * be more complicated to do otherwise.)  Because of the larger range of
+	 * negative signed integers, we build "value" in the negative and then
+	 * flip the sign at the end, catching most-negative-number overflow if
+	 * necessary.
+	 */
+
 	for (; *s; s++)
 	{
 		/* we look for digits as long as we have found less */
 		/* than the required number of decimal places */
 		if (isdigit((unsigned char) *s) && (!seen_dot || dec < fpoint))
 		{
-			value = (value * 10) + (*s - '0');
+			Cash newvalue = (value * 10) - (*s - '0');
+
+			if (newvalue / 10 != value)
+				ereport(ERROR,
+						(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+						 errmsg("value \"%s\" is out of range for type money",
+								str)));
+
+			value = newvalue;
 
 			if (seen_dot)
 				dec++;
@@ -214,11 +231,27 @@ cash_in(PG_FUNCTION_ARGS)
 
 	/* round off if there's another digit */
 	if (isdigit((unsigned char) *s) && *s >= '5')
-		value++;
+		value--;  /* remember we build the value in the negative */
+
+	if (value > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("value \"%s\" is out of range for type money",
+						str)));
 
 	/* adjust for less than required decimal places */
 	for (; dec < fpoint; dec++)
-		value *= 10;
+	{
+		Cash newvalue = value * 10;
+
+		if (newvalue / 10 != value)
+			ereport(ERROR,
+					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+					 errmsg("value \"%s\" is out of range for type money",
+							str)));
+
+		value = newvalue;
+	}
 
 	/*
 	 * should only be trailing digits followed by whitespace, right paren,
@@ -247,7 +280,19 @@ cash_in(PG_FUNCTION_ARGS)
 							str)));
 	}
 
-	result = value * sgn;
+	/* If the value is supposed to be positive, flip the sign, but check for
+	 * the most negative number. */
+	if (sgn > 0)
+	{
+		result = -value;
+		if (result < 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+					 errmsg("value \"%s\" is out of range for type money",
+							str)));
+	}
+	else
+		result = value;
 
 #ifdef CASHDEBUG
 	printf("cashin- result is " INT64_FORMAT "\n", result);