[PATCH] sfdisk: fix calculation due to type mismatch (ix86)

[PATCH] sfdisk: fix calculation due to type mismatch (ix86)

[Petr Uzel]

Instructing sfdisk to create one partition spanning
across entire disk (",,") on 32bit system, if the disk
is sufficiently large (~2TB) leads to wrong calculation
in compute_start_sect() due to type mismatch.

Can be reproduced as:

--------------------------
linux-3ln5:~ # modprobe scsi_debug virtual_gb=2000
linux-3ln5:~ # sfdisk /dev/sda <<< ',,'
Checking that no-one is using this disk right now ...
OK

Disk /dev/sda: 261083 cylinders, 255 heads, 63 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
sfdisk:  /dev/sda: unrecognized partition table type

Old situation:
sfdisk: No partitions found

no room for partition descriptor
sfdisk: bad input
--------------------------

Addresses: https://bugzilla.novell.com/show_bug.cgi?id=754789
Reported-by: Dan Mares <dan.mares@norcrossgroup.com>
Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
---
 fdisk/sfdisk.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fdisk/sfdisk.c b/fdisk/sfdisk.c
index 87929d3..350bf1d 100644
--- a/fdisk/sfdisk.c
+++ b/fdisk/sfdisk.c
@@ -1991,7 +1991,7 @@ static int
 compute_start_sect(struct part_desc *p, struct part_desc *ep) {
     unsigned long long base;
     int inc = (DOS && B.sectors) ? B.sectors : 1;
-    int delta;
+    long long delta;
 
     if (ep && p->start + p->size >= ep->start + 1)
 	delta = p->start - ep->start - inc;
@@ -2006,7 +2006,7 @@ compute_start_sect(struct part_desc *p, struct part_desc *ep) {
 	p->size += delta;
 	if (is_extended(p->p.sys_type) && boxes == ONESECTOR)
 	    p->size = inc;
-	else if ((ssize_t) old_size <= (ssize_t) - delta) {
+	else if ((long long) old_size <= -delta) {
 	    my_warn(_("no room for partition descriptor\n"));
 	    return 0;
 	}
-- 
1.7.7

Re: [PATCH] sfdisk: fix calculation due to type mismatch (ix86)

[Karel Zak]

On Fri, Apr 06, 2012 at 04:53:13PM +0200, Petr Uzel wrote:
> Addresses: https://bugzilla.novell.com/show_bug.cgi?id=754789
> Reported-by: Dan Mares <dan.mares@norcrossgroup.com>
> Signed-off-by: Petr Uzel <petr.uzel@suse.cz>

 Ah.. pretty dirty bug. Applied, thanks.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: [PATCH] sfdisk: fix calculation due to type mismatch (ix86)

[Jonathan Nieder]

Hi Karel,

Karel Zak wrote:
> On Fri, Apr 06, 2012 at 04:53:13PM +0200, Petr Uzel wrote:

>> Addresses: https://bugzilla.novell.com/show_bug.cgi?id=754789
>> Reported-by: Dan Mares <dan.mares@norcrossgroup.com>
>> Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
>
>  Ah.. pretty dirty bug. Applied, thanks.

(This is 9c45d49fe01c "sfdisk: fix calculation due to type mismatch
(ix86)".)  Thanks.  Do you think this fix might belong in currently
maintained stable/ branches, too, and if so, how can I help make that
happen?

Context: http://bugs.debian.org/670127

Sincerely,
Jonathan

Re: [PATCH] sfdisk: fix calculation due to type mismatch (ix86)

[Karel Zak]

On Wed, Apr 25, 2012 at 10:16:03AM -0500, Jonathan Nieder wrote:
> >> Addresses: https://bugzilla.novell.com/show_bug.cgi?id=754789
> >> Reported-by: Dan Mares <dan.mares@norcrossgroup.com>
> >> Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
> >
> >  Ah.. pretty dirty bug. Applied, thanks.
> 
> (This is 9c45d49fe01c "sfdisk: fix calculation due to type mismatch
> (ix86)".)  Thanks.  Do you think this fix might belong in currently
> maintained stable/ branches, too, and if so, how can I help make that
> happen?

 I'm going to release 2.21.2 next week.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com