Check for underflow as well as overflow when scaling negative numbers.

ok millert@

diff --git a/lib/libutil/fmt_scaled.c b/lib/libutil/fmt_scaled.c
index f06c727..0b443d4 100644 (file)
--- a/lib/libutil/fmt_scaled.c
+++ b/lib/libutil/fmt_scaled.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: fmt_scaled.c,v 1.20 2021/06/20 14:08:42 tb Exp $      */
+/*     $OpenBSD: fmt_scaled.c,v 1.21 2022/03/11 07:29:53 dtucker Exp $ */
 
 /*
  * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
@@ -185,7 +185,8 @@ scan_scaled(char *scaled, long long *result)
                        /* truncate fpart so it does't overflow.
                         * then scale fractional part.
                         */
-                       while (fpart >= LLONG_MAX / scale_fact) {
+                       while (fpart >= LLONG_MAX / scale_fact ||
+                           fpart <= LLONG_MIN / scale_fact) {
                                fpart /= 10;
                                fract_digits--;
                        }

diff --git a/regress/lib/libutil/fmt_scaled/fmt_test.c b/regress/lib/libutil/fmt_scaled/fmt_test.c
index f35c445..308c2ce 100644 (file)
--- a/regress/lib/libutil/fmt_scaled/fmt_test.c
+++ b/regress/lib/libutil/fmt_scaled/fmt_test.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: fmt_test.c,v 1.17 2021/06/20 14:09:59 tb Exp $ */
+/* $OpenBSD: fmt_test.c,v 1.18 2022/03/11 07:29:53 dtucker Exp $ */
 
 /*
  * Combined tests for fmt_scaled and scan_scaled.
@@ -188,6 +188,9 @@ struct {                                    /* the test cases */
        { "",           0, 0 },                 /* boundary */
        { "--1", -1, EINVAL },
        { "++42", -1, EINVAL },
+       { "-.060000000000000000E", -69175290276410818, 0 },
+       { "-.600000000000000000E", -691752902764108185, 0 },
+       { "-60000000000000000E", 0, ERANGE },
        { "SCALE_OVERFLOW", 0, ERANGE },
        { "SCALE_UNDERFLOW", 0, ERANGE },
        { "LLONG_MAX_K", (LLONG_MAX / 1024) * 1024, 0 },