expr(1): Fix overflow detection when operand is INTMAX_MIN

PR:		227329
Submitted by:	Tobias Stoeckmann <tobias AT stoeckmann.org>
This commit is contained in:
Conrad Meyer 2018-04-14 04:35:10 +00:00
parent f6e61711ed
commit 41bd31e656
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=332499

View file

@ -422,11 +422,9 @@ op_plus(struct val *a, struct val *b)
void
assert_minus(intmax_t a, intmax_t b, intmax_t r)
{
/* special case subtraction of INTMAX_MIN */
if (b == INTMAX_MIN && a < 0)
if ((a >= 0 && b < 0 && r <= 0) ||
(a < 0 && b > 0 && r >= 0))
errx(ERR_EXIT, "overflow");
/* check addition of negative subtrahend */
assert_plus(a, -b, r);
}
struct val *