Add overflow checks to money type.

None of the arithmetic functions for the the money type handle
overflow.  This commit introduces several helper functions with
overflow checking and makes use of them in the money type's
arithmetic functions.

Fixes bug #18240.

Reported-by: Alexander Lakhin
Author: Joseph Koshakow
Discussion: https://postgr.es/m/18240-c5da758d7dc1ecf0%40postgresql.org
Discussion: https://postgr.es/m/CAAvxfHdBPOyEGS7s%2Bxf4iaW0-cgiq25jpYdWBqQqvLtLe_t6tw%40mail.gmail.com
Backpatch-through: 12

1 files changed, 94 insertions, 80 deletions

diff --git a/src/backend/utils/adt/cash.c b/src/backend/utils/adt/cash.c
index 32fbad2f57d..b20c358486d 100644
--- a/src/backend/utils/adt/cash.c
+++ b/src/backend/utils/adt/cash.c
@@ -26,6 +26,7 @@
 #include "libpq/pqformat.h"
 #include "utils/builtins.h"
 #include "utils/cash.h"
+#include "utils/float.h"
 #include "utils/numeric.h"
 #include "utils/pg_locale.h"
 
@@ -86,6 +87,82 @@ num_word(Cash value)
 	return buf;
 }								/* num_word() */
 
+static inline Cash
+cash_pl_cash(Cash c1, Cash c2)
+{
+	Cash		res;
+
+	if (unlikely(pg_add_s64_overflow(c1, c2, &res)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("money out of range")));
+
+	return res;
+}
+
+static inline Cash
+cash_mi_cash(Cash c1, Cash c2)
+{
+	Cash		res;
+
+	if (unlikely(pg_sub_s64_overflow(c1, c2, &res)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("money out of range")));
+
+	return res;
+}
+
+static inline Cash
+cash_mul_float8(Cash c, float8 f)
+{
+	float8		res = rint(float8_mul((float8) c, f));
+
+	if (unlikely(isnan(res) || !FLOAT8_FITS_IN_INT64(res)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("money out of range")));
+
+	return (Cash) res;
+}
+
+static inline Cash
+cash_div_float8(Cash c, float8 f)
+{
+	float8		res = rint(float8_div((float8) c, f));
+
+	if (unlikely(isnan(res) || !FLOAT8_FITS_IN_INT64(res)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("money out of range")));
+
+	return (Cash) res;
+}
+
+static inline Cash
+cash_mul_int64(Cash c, int64 i)
+{
+	Cash		res;
+
+	if (unlikely(pg_mul_s64_overflow(c, i, &res)))
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("money out of range")));
+
+	return res;
+}
+
+static inline Cash
+cash_div_int64(Cash c, int64 i)
+{
+	if (unlikely(i == 0))
+		ereport(ERROR,
+				(errcode(ERRCODE_DIVISION_BY_ZERO),
+				 errmsg("division by zero")));
+
+	return c / i;
+}
+
 /* cash_in()
  * Convert a string to a cash data type.
  * Format is [$]###[,]###[.##]
@@ -612,11 +689,8 @@ cash_pl(PG_FUNCTION_ARGS)
 {
 	Cash		c1 = PG_GETARG_CASH(0);
 	Cash		c2 = PG_GETARG_CASH(1);
-	Cash		result;
-
-	result = c1 + c2;
 
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_pl_cash(c1, c2));
 }
 
 
@@ -628,11 +702,8 @@ cash_mi(PG_FUNCTION_ARGS)
 {
 	Cash		c1 = PG_GETARG_CASH(0);
 	Cash		c2 = PG_GETARG_CASH(1);
-	Cash		result;
-
-	result = c1 - c2;
 
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mi_cash(c1, c2));
 }
 
 
@@ -664,10 +735,8 @@ cash_mul_flt8(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	float8		f = PG_GETARG_FLOAT8(1);
-	Cash		result;
 
-	result = rint(c * f);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_float8(c, f));
 }
 
 
@@ -679,10 +748,8 @@ flt8_mul_cash(PG_FUNCTION_ARGS)
 {
 	float8		f = PG_GETARG_FLOAT8(0);
 	Cash		c = PG_GETARG_CASH(1);
-	Cash		result;
 
-	result = rint(f * c);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_float8(c, f));
 }
 
 
@@ -694,15 +761,8 @@ cash_div_flt8(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	float8		f = PG_GETARG_FLOAT8(1);
-	Cash		result;
 
-	if (f == 0.0)
-		ereport(ERROR,
-				(errcode(ERRCODE_DIVISION_BY_ZERO),
-				 errmsg("division by zero")));
-
-	result = rint(c / f);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_div_float8(c, f));
 }
 
 
@@ -714,10 +774,8 @@ cash_mul_flt4(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	float4		f = PG_GETARG_FLOAT4(1);
-	Cash		result;
 
-	result = rint(c * (float8) f);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_float8(c, (float8) f));
 }
 
 
@@ -729,10 +787,8 @@ flt4_mul_cash(PG_FUNCTION_ARGS)
 {
 	float4		f = PG_GETARG_FLOAT4(0);
 	Cash		c = PG_GETARG_CASH(1);
-	Cash		result;
 
-	result = rint((float8) f * c);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_float8(c, (float8) f));
 }
 
 
@@ -745,15 +801,8 @@ cash_div_flt4(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	float4		f = PG_GETARG_FLOAT4(1);
-	Cash		result;
-
-	if (f == 0.0)
-		ereport(ERROR,
-				(errcode(ERRCODE_DIVISION_BY_ZERO),
-				 errmsg("division by zero")));
 
-	result = rint(c / (float8) f);
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_div_float8(c, (float8) f));
 }
 
 
@@ -765,10 +814,8 @@ cash_mul_int8(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int64		i = PG_GETARG_INT64(1);
-	Cash		result;
 
-	result = c * i;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, i));
 }
 
 
@@ -780,10 +827,8 @@ int8_mul_cash(PG_FUNCTION_ARGS)
 {
 	int64		i = PG_GETARG_INT64(0);
 	Cash		c = PG_GETARG_CASH(1);
-	Cash		result;
 
-	result = i * c;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, i));
 }
 
 /* cash_div_int8()
@@ -794,16 +839,8 @@ cash_div_int8(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int64		i = PG_GETARG_INT64(1);
-	Cash		result;
-
-	if (i == 0)
-		ereport(ERROR,
-				(errcode(ERRCODE_DIVISION_BY_ZERO),
-				 errmsg("division by zero")));
 
-	result = c / i;
-
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_div_int64(c, i));
 }
 
 
@@ -815,10 +852,8 @@ cash_mul_int4(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int32		i = PG_GETARG_INT32(1);
-	Cash		result;
 
-	result = c * i;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, (int64) i));
 }
 
 
@@ -830,10 +865,8 @@ int4_mul_cash(PG_FUNCTION_ARGS)
 {
 	int32		i = PG_GETARG_INT32(0);
 	Cash		c = PG_GETARG_CASH(1);
-	Cash		result;
 
-	result = i * c;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, (int64) i));
 }
 
 
@@ -846,16 +879,8 @@ cash_div_int4(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int32		i = PG_GETARG_INT32(1);
-	Cash		result;
-
-	if (i == 0)
-		ereport(ERROR,
-				(errcode(ERRCODE_DIVISION_BY_ZERO),
-				 errmsg("division by zero")));
-
-	result = c / i;
 
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_div_int64(c, (int64) i));
 }
 
 
@@ -867,10 +892,8 @@ cash_mul_int2(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int16		s = PG_GETARG_INT16(1);
-	Cash		result;
 
-	result = c * s;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, (int64) s));
 }
 
 /* int2_mul_cash()
@@ -881,10 +904,8 @@ int2_mul_cash(PG_FUNCTION_ARGS)
 {
 	int16		s = PG_GETARG_INT16(0);
 	Cash		c = PG_GETARG_CASH(1);
-	Cash		result;
 
-	result = s * c;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_mul_int64(c, (int64) s));
 }
 
 /* cash_div_int2()
@@ -896,15 +917,8 @@ cash_div_int2(PG_FUNCTION_ARGS)
 {
 	Cash		c = PG_GETARG_CASH(0);
 	int16		s = PG_GETARG_INT16(1);
-	Cash		result;
 
-	if (s == 0)
-		ereport(ERROR,
-				(errcode(ERRCODE_DIVISION_BY_ZERO),
-				 errmsg("division by zero")));
-
-	result = c / s;
-	PG_RETURN_CASH(result);
+	PG_RETURN_CASH(cash_div_int64(c, (int64) s));
 }
 
 /* cashlarger()