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From: Aleksandr Nogikh <nogikh@google.com>
Date: Thu, 29 Feb 2024 16:40:05 +0100
Message-ID: <CANp29Y6hPF--pjWCa4bsAXWY15XoP2kmSg8BFP4ATGUpVbQgHQ@mail.gmail.com>
Subject: Re: [syzbot] [usb-storage?] divide error in isd200_ata_command
To: Alan Stern <stern@rowland.harvard.edu>
Cc: syzbot <syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com>, 
	bvanassche@acm.org, emilne@redhat.com, gregkh@linuxfoundation.org, 
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, 
	martin.petersen@oracle.com, syzkaller-bugs@googlegroups.com, 
	tasos@tasossah.com, usb-storage@lists.one-eyed-alien.net
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Wed, Feb 28, 2024 at 8:18=E2=80=AFPM Alan Stern <stern@rowland.harvard.e=
du> wrote:
>
> On Wed, Feb 28, 2024 at 05:52:50PM +0100, Aleksandr Nogikh wrote:
> > Hi Alan,
> >
> > Please try it once more with the full commit hash.
>
> Thanks for the advice.  Are you a good person to complain to about the
> difference between what syzbot provides and what it will accept?  This
> bug report states
>
> HEAD commit:    f2e367d6ad3b Merge tag 'for-6.8/dm-fix-3' of git://git.ke=
r..
> git tree:       upstream
>
> But if I specify "upstream" as the git tree on a syz test request, it
> doesn't accept it.  Now you're suggesting that if I put f2e367d6ad3b as
> the commit ID, it won't accept it.
>
> There's probably already a bugfix request for this, but I'd like to push
> on it some more.  Syzbot's output should be acceptable as its input!

That all totally makes sense. Thanks for highlighting the problems!

For accepting "upstream" (and alike) as input, there was already a github i=
ssue:
https://github.com/google/syzkaller/issues/2265
That syzbot is not able to fetch commits by their short hashes was
only discovered yesterday.

I've just sent PRs with fixes for both issues.

If there's anything else that can make syzbot reports better, please
let me know :)

--=20
Aleksandr

>
> Okay, here goes with the full commit ID...
>
> Alan Stern
>
> On Mon, Feb 26, 2024 at 01:42:26AM -0800, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    f2e367d6ad3b Merge tag 'for-6.8/dm-fix-3' of git://git.=
ker..
> > git tree:       upstream
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=3D114e10e4180=
000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3Deff9f3183d0=
a20dd
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3D28748250ab47a=
8f04100
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for D=
ebian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D1064b3721=
80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D10aca6ac180=
000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/c55ca1fdc5ad/d=
isk-f2e367d6.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/4556a82fb4ed/vmli=
nux-f2e367d6.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/95338ed9dad1=
/bzImage-f2e367d6.xz
> >
> > The issue was bisected to:
> >
> > commit 321da3dc1f3c92a12e3c5da934090d2992a8814c
> > Author: Martin K. Petersen <martin.petersen@oracle.com>
> > Date:   Tue Feb 13 14:33:06 2024 +0000
> >
> >     scsi: sd: usb_storage: uas: Access media prior to querying device p=
roperties
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=3D15a3934a=
180000
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=3D17a3934a=
180000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=3D13a3934a180=
000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the co=
mmit:
> > Reported-by: syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com
> > Fixes: 321da3dc1f3c ("scsi: sd: usb_storage: uas: Access media prior to=
 querying device properties")
> >
> > divide error: 0000 [#1] PREEMPT SMP KASAN PTI
> > CPU: 0 PID: 5070 Comm: usb-storage Not tainted 6.8.0-rc5-syzkaller-0029=
7-gf2e367d6ad3b #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS=
 Google 01/25/2024
> > RIP: 0010:isd200_scsi_to_ata drivers/usb/storage/isd200.c:1318 [inline]
> > RIP: 0010:isd200_ata_command+0x776/0x2380 drivers/usb/storage/isd200.c:=
1529
>
> #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux=
git/ f2e367d6ad3bdc527c2b14e759c2f010d6b2b7a1
> Index: usb-devel/drivers/usb/storage/isd200.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- usb-devel.orig/drivers/usb/storage/isd200.c
> +++ usb-devel/drivers/usb/storage/isd200.c
> @@ -1105,7 +1105,7 @@ static void isd200_dump_driveid(struct u
>  static int isd200_get_inquiry_data( struct us_data *us )
>  {
>         struct isd200_info *info =3D (struct isd200_info *)us->extra;
> -       int retStatus =3D ISD200_GOOD;
> +       int retStatus;
>         u16 *id =3D info->id;
>
>         usb_stor_dbg(us, "Entering isd200_get_inquiry_data\n");
> @@ -1137,6 +1137,13 @@ static int isd200_get_inquiry_data( stru
>                                 isd200_fix_driveid(id);
>                                 isd200_dump_driveid(us, id);
>
> +                               /* Prevent division by 0 in isd200_scsi_t=
o_ata() */
> +                               if (id[ATA_ID_HEADS] =3D=3D 0 || id[ATA_I=
D_SECTORS] =3D=3D 0) {
> +                                       usb_stor_dbg(us, "   Invalid ATA =
Identify data\n");
> +                                       retStatus =3D ISD200_ERROR;
> +                                       goto Done;
> +                               }
> +
>                                 memset(&info->InquiryData, 0, sizeof(info=
->InquiryData));
>
>                                 /* Standard IDE interface only supports d=
isks */
> @@ -1202,6 +1209,7 @@ static int isd200_get_inquiry_data( stru
>                 }
>         }
>
> + Done:
>         usb_stor_dbg(us, "Leaving isd200_get_inquiry_data %08X\n", retSta=
tus);
>
>         return(retStatus);
> @@ -1481,22 +1489,27 @@ static int isd200_init_info(struct us_da
>
>  static int isd200_Initialization(struct us_data *us)
>  {
> +       int rc =3D 0;
> +
>         usb_stor_dbg(us, "ISD200 Initialization...\n");
>
>         /* Initialize ISD200 info struct */
>
> -       if (isd200_init_info(us) =3D=3D ISD200_ERROR) {
> +       if (isd200_init_info(us) < 0) {
>                 usb_stor_dbg(us, "ERROR Initializing ISD200 Info struct\n=
");
> +               rc =3D -ENOMEM;
>         } else {
>                 /* Get device specific data */
>
> -               if (isd200_get_inquiry_data(us) !=3D ISD200_GOOD)
> +               if (isd200_get_inquiry_data(us) !=3D ISD200_GOOD) {
>                         usb_stor_dbg(us, "ISD200 Initialization Failure\n=
");
> -               else
> +                       rc =3D -EINVAL;
> +               } else {
>                         usb_stor_dbg(us, "ISD200 Initialization complete\=
n");
> +               }
>         }
>
> -       return 0;
> +       return rc;
>  }
>
>
>
>