On Sun, May 06, 2012 at 02:10:25PM +0200, Davidlohr Bueso wrote:
> From: Davidlohr Bueso <dave@xxxxxxx>
>
> When the HDIO_GETGEO ioctl fails on non IRIX/MIPS platforms (ie:
> inappropriate ioctl for device) the variables that describe the
> geometry are compromissed. One clear example is a division by 0 bug
> because the cylinder size is 0 is verify_sgi():
I agree with the change, however I think that more descriptive error
message should be printed; see below.
>
> $> fdisk sgi.img
> Welcome to fdisk (util-linux 2.21.392-4b1c).
>
> ...
>
> Command (m for help): x
>
> Expert command (m for help): g
> Building a new SGI disklabel.
> Partition 11 of type SGI volume and of size 7.9 MiB is set
> Floating point exception
>
> Fix this by simply exiting the program instead of leaving it in a vulnerable state.
>
> Signed-off-by: Davidlohr Bueso <dave@xxxxxxx>
> ---
> fdisk/fdisksgilabel.c | 39 ++++++++++++++++++++-------------------
> 1 files changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/fdisk/fdisksgilabel.c b/fdisk/fdisksgilabel.c
> index 822f55d..b61f102 100644
> --- a/fdisk/fdisksgilabel.c
> +++ b/fdisk/fdisksgilabel.c
> @@ -705,25 +705,26 @@ create_sgilabel(void)
> res = blkdev_get_sectors(fd, &llsectors);
>
> #ifdef HDIO_GETGEO
> - if (!ioctl(fd, HDIO_GETGEO, &geometry)) {
> - heads = geometry.heads;
> - sectors = geometry.sectors;
> - if (res == 0) {
> - /* the get device size ioctl was successful */
> - unsigned long long llcyls;
> - llcyls = llsectors / (heads * sectors * sec_fac);
> - cylinders = llcyls;
> - if (cylinders != llcyls) /* truncated? */
> - cylinders = ~0;
> - } else {
> - /* otherwise print error and use truncated version */
> - cylinders = geometry.cylinders;
> - fprintf(stderr,
> - _("Warning: BLKGETSIZE ioctl failed on %s. "
> - "Using geometry cylinder value of %d.\n"
> - "This value may be truncated for devices"
> - " > 33.8 GB.\n"), disk_device, cylinders);
> - }
> + if (ioctl(fd, HDIO_GETGEO, &geometry) < 0)
> + err(EXIT_FAILURE, _("ioctl failed on %s"), disk_device);
s/"ioctl failed..."/"HDIO_GETGEO ioctl failed..."
[SNIP]
Petr
--
Petr Uzel
IRC: ptr_uzl @ freenode
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