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- add a sanity check to avoid possible division by zero

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- adjust sector numbers _after_ "Sanity check the data against all zeroes"

Should close PR bin/37656.
This commit is contained in:
tsutsui 2008-01-20 06:39:31 +00:00
parent 8c03790350
commit aa7cb7b8f0
1 changed files with 7 additions and 5 deletions
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12
sbin/fdisk/fdisk.c
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@ -1,4 +1,4 @@
/* $NetBSD: fdisk.c,v 1.113 2007/12/23 10:43:57 apb Exp $ */
/* $NetBSD: fdisk.c,v 1.114 2008/01/20 06:39:31 tsutsui Exp $ */
/*
* Mach Operating System
@ -39,7 +39,7 @@
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: fdisk.c,v 1.113 2007/12/23 10:43:57 apb Exp $");
__RCSID("$NetBSD: fdisk.c,v 1.114 2008/01/20 06:39:31 tsutsui Exp $");
#endif /* not lint */
#define MBRPTYPENAMES
@ -1486,7 +1486,7 @@ intuit_translated_geometry(void)
a2 -= s2;
num = (uint64_t)h1 * a2 - (uint64_t)h2 * a1;
denom = (uint64_t)c2 * a1 - (uint64_t)c1 * a2;
if (denom != 0 && num % denom == 0) {
if (denom != 0 && num != 0 && num % denom == 0) {
xheads = num / denom;
xsectors = a1 / (c1 * xheads + h1);
break;
@ -1551,18 +1551,20 @@ get_mapping(int i, unsigned int *cylinder, unsigned int *head, unsigned int *sec
if (i % 2 == 0) {
*cylinder = MBR_PCYL(part->mbrp_scyl, part->mbrp_ssect);
*head = part->mbrp_shd;
*sector = MBR_PSECT(part->mbrp_ssect) - 1;
*sector = MBR_PSECT(part->mbrp_ssect);
*absolute = le32toh(part->mbrp_start);
} else {
*cylinder = MBR_PCYL(part->mbrp_ecyl, part->mbrp_esect);
*head = part->mbrp_ehd;
*sector = MBR_PSECT(part->mbrp_esect) - 1;
*sector = MBR_PSECT(part->mbrp_esect);
*absolute = le32toh(part->mbrp_start)
+ le32toh(part->mbrp_size) - 1;
}
/* Sanity check the data against all zeroes */
if ((*cylinder == 0) && (*sector == 0) && (*head == 0))
return -1;
/* sector numbers in the MBR partition table start at 1 */
*sector = *sector - 1;
/* Sanity check the data against max values */
if ((((*cylinder * MAXHEAD) + *head) * MAXSECTOR + *sector) < *absolute)
/* cannot be a CHS mapping */