bin/140185: [patch] expand_number() does not detect overflow in numeric part

[Mikko Tyolajarvi]

>Number:         140185
>Category:       bin
>Synopsis:       [patch] expand_number() does not detect overflow in numeric part
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 02 00:30:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Mikko Tyolajarvi
>Release:        7.2-STABLE
>Organization:
>Environment:
FreeBSD antec.home 7.2-STABLE FreeBSD 7.2-STABLE #1: Fri Sep  4 19:36:49 PDT 2009     mikko at antec.home:/usr/obj/usr/src/sys/GENERIC  i386

>Description:
The expand_number() function will silently truncate the numeric part
to the size of a maxint_t and if there is no suffix, no error is returned.
Overflow in strings that include a suffix is detected (e.g. "8E")

The patch is against -CURRENT.
>How-To-Repeat:
Compile and run this program with no arguments.  It should print "ok".

#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <libutil.h>
#include <inttypes.h>

int
main(int argc, const char *argv[])
{
    int64_t num = 0;
    const char *s;
    int rc;

    s = (argc > 1) ? argv[1] : "9223372036854775808";  /* 2^63 */
    rc = expand_number(s, &num);
    if (rc < 0 && errno == ERANGE) {
	printf("ok\n");
	return 0;
    }
    printf("nope. rc = %d, num = %lld\n", rc, num);
    return 1;
}

>Fix:
Check return value and errno from strtoimax().  Patch attached.

Patch attached with submission follows:

--- expand_number.c.orig	2009-11-01 16:10:42.000000000 -0800
+++ expand_number.c	2009-11-01 16:12:54.000000000 -0800
@@ -52,10 +52,17 @@
 	static const char unit[] = "bkmgtpe";
 	char *endptr, s;
 	int64_t number;
-	int i;
+	int i, oerrno;
 
+	oerrno = errno;
+	errno = 0;
 	number = strtoimax(buf, &endptr, 0);
 
+	if ((number == INTMAX_MIN || number == INTMAX_MAX) && errno == ERANGE)
+		return (-1);
+
+	errno = oerrno;
+
 	if (endptr == buf) {
 		/* No valid digits. */
 		errno = EINVAL;


>Release-Note:
>Audit-Trail:
>Unformatted: