The errcheck() function treats an errno of ERANGE or EDOM as something

to report, so make sure errno is set to zero before invoking a
function to check so that a previous such errno value won't result
in a false positive.  This could happen simply due to input line fields
that looked enough like floating-point input to trigger ERANGE.

Problem noted by Jordan Geoghegan (jordan (at) geoghegan.ca), with
clue from Ze' Loff (zeloff (at) zeloff.org)

ok millert@

1 files changed, 11 insertions, 3 deletions

diff --git a/usr.bin/awk/run.c b/usr.bin/awk/run.c
index 20e169cdd40..bb0038555e9 100644
--- a/usr.bin/awk/run.c
+++ b/usr.bin/awk/run.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: run.c,v 1.44 2019/08/13 10:45:56 fcambus Exp $	*/
+/*	$OpenBSD: run.c,v 1.45 2020/06/08 03:22:23 guenther Exp $	*/
 /****************************************************************
 Copyright (C) Lucent Technologies 1997
 All Rights Reserved
@@ -26,6 +26,7 @@ THIS SOFTWARE.
 #define DEBUG
 #include <stdio.h>
 #include <ctype.h>
+#include <errno.h>
 #include <setjmp.h>
 #include <limits.h>
 #include <math.h>
@@ -1041,8 +1042,10 @@ Cell *arith(Node **a, int n)	/* a[0] + a[1], etc.  also -a[0] */
 	case POWER:
 		if (j >= 0 && modf(j, &v) == 0.0)	/* pos integer exponent */
 			i = ipow(i, (int) j);
-		else
+		else {
+			errno = 0;
 			i = errcheck(pow(i, j), "pow");
+		}
 		break;
 	default:	/* can't happen */
 		FATAL("illegal arithmetic operator %d", n);
@@ -1135,8 +1138,10 @@ Cell *assign(Node **a, int n)	/* a[0] = a[1], a[0] += a[1], etc. */
 	case POWEQ:
 		if (yf >= 0 && modf(yf, &v) == 0.0)	/* pos integer exponent */
 			xf = ipow(xf, (int) yf);
-		else
+		else {
+			errno = 0;
 			xf = errcheck(pow(xf, yf), "pow");
+		}
 		break;
 	default:
 		FATAL("illegal assignment operator %d", n);
@@ -1499,12 +1504,15 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 			u = strlen(getsval(x));
 		break;
 	case FLOG:
+		errno = 0;
 		u = errcheck(log(getfval(x)), "log"); break;
 	case FINT:
 		modf(getfval(x), &u); break;
 	case FEXP:
+		errno = 0;
 		u = errcheck(exp(getfval(x)), "exp"); break;
 	case FSQRT:
+		errno = 0;
 		u = errcheck(sqrt(getfval(x)), "sqrt"); break;
 	case FSIN:
 		u = sin(getfval(x)); break;