Re: PR/47879 CVS commit: src/sys/dev

[Takahiro HAYASHI <t-hash%abox3.so-net.ne.jp@localhost>]

The following reply was made to PR kern/47879; it has been noted by GNATS.

From: Takahiro HAYASHI <t-hash%abox3.so-net.ne.jp@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost, 
netbsd-bugs%NetBSD.org@localhost
Subject: Re: PR/47879 CVS commit: src/sys/dev
Date: Tue, 04 Jun 2013 05:28:55 +0900

 On Mon,  3 Jun 2013 16:45:01 +0000 (UTC)
 "Christos Zoulas" <christos%netbsd.org@localhost> wrote:
 
 > The following reply was made to PR kern/47879; it has been noted by GNATS.
 > 
 > From: "Christos Zoulas" <christos%netbsd.org@localhost>
 > To: gnats-bugs%gnats.NetBSD.org@localhost
 > Cc: 
 > Subject: PR/47879 CVS commit: src/sys/dev
 > Date: Mon, 3 Jun 2013 12:42:32 -0400
 > 
 >  Module Name:        src
 >  Committed By:       christos
 >  Date:               Mon Jun  3 16:42:32 UTC 2013
 >  
 >  Modified Files:
 >      src/sys/dev: vnd.c vndvar.h
 >  
 >  Log Message:
 >  PR/47879: Takahiro HAYASHI: vnd cannot handle disk image larger than 2TiB
 >  change size_t to uint64_t where needed.
 
 Thanks for commit but the fix is insufficient.
 
 In function vnd_set_geometry() of src/sys/dev/vnd.c, sectors per unit
 is the product of num of sectors, tracks and cylinders.
 This may cause interger overflow.
 
        dg->dg_secperunit = vnd->sc_geom.vng_nsectors *
            vnd->sc_geom.vng_ntracks * vnd->sc_geom.vng_ncylinders;
 
 The typeof right side variables are all uint32_t, so the result is
 calculated in interger.
 
 One of solutions to avoid overflow is to start right side
 with "1LL *".
 
        dg->dg_secperunit = 1LL * vnd->sc_geom.vng_nsectors *
            vnd->sc_geom.vng_ntracks * vnd->sc_geom.vng_ncylinders;
 
 Or cast first variable to int64_t.
 
        dg->dg_secperunit = (int64_t)vnd->sc_geom.vng_nsectors *
            vnd->sc_geom.vng_ntracks * vnd->sc_geom.vng_ncylinders;
 
 --
 t-hash