Re: [PATCH] mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main()

[Martin K. Petersen]

Gen,

> In _ctl_ioctl_main(), 'ioctl_header' is fetched the first time from 
> userspace. 'ioctl_header.ioc_number' is then checked. The legal result 
> is saved to 'ioc'. Then, in condition MPT3COMMAND, the whole struct is
> fetched again from the userspace. Then _ctl_do_mpt_command() is called,
> 'ioc' and 'karg' as inputs.
>
> However, a malicious user can change the 'ioc_number' between the two 
> fetches, which will cause a potential security issues.  Moreover, a 
> malicious user can provide a valid 'ioc_number' to pass the check in 
> first fetch, and then modify it in the second fetch.
>
> To fix this, we need to recheck the 'ioc_number' in the second fetch.

Applied to 5.3/scsi-queue, thanks.

-- 
Martin K. Petersen  Oracle Linux Engineering

Re: [PATCH] mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main()

[Gen Zhang]

On Tue, May 28, 2019 at 11:44:35AM +0530, Suganath Prabu Subramani wrote:
> Please consider this patch as Ack-by: Suganath Prabu S
> 
> 
> Thanks,
> Suganath.
> 
> 
> On Mon, May 27, 2019 at 6:27 AM Gen Zhang  wrote:
> >
> > In _ctl_ioctl_main(), 'ioctl_header' is fetched the first time from
> > userspace. 'ioctl_header.ioc_number' is then checked. The legal result
> > is saved to 'ioc'. Then, in condition MPT3COMMAND, the whole struct is
> > fetched again from the userspace. Then _ctl_do_mpt_command() is called,
> > 'ioc' and 'karg' as inputs.
> >
> > However, a malicious user can change the 'ioc_number' between the two
> > fetches, which will cause a potential security issues.  Moreover, a
> > malicious user can provide a valid 'ioc_number' to pass the check in
> > first fetch, and then modify it in the second fetch.
> >
> > To fix this, we need to recheck the 'ioc_number' in the second fetch.
> >
> > Signed-off-by: Gen Zhang 
> > ---
> > diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c 
> > b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> > index b2bb47c..5181c03 100644
> > --- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> > +++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> > @@ -2319,6 +2319,10 @@ _ctl_ioctl_main(struct file *file, unsigned int cmd, 
> > void __user *arg,
> > break;
> > }
> >
> > +   if (karg.hdr.ioc_number != ioctl_header.ioc_number) {
> > +   ret = -EINVAL;
> > +   break;
> > +   }
> > if (_IOC_SIZE(cmd) == sizeof(struct mpt3_ioctl_command)) {
> > uarg = arg;
> > ret = _ctl_do_mpt_command(ioc, karg, &uarg->mf);
Thanks for your reply, Suganath.

Thanks
Gen

Re: [PATCH] mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main()

[Suganath Prabu Subramani]

Please consider this patch as Ack-by: Suganath Prabu S


Thanks,
Suganath.


On Mon, May 27, 2019 at 6:27 AM Gen Zhang  wrote:
>
> In _ctl_ioctl_main(), 'ioctl_header' is fetched the first time from
> userspace. 'ioctl_header.ioc_number' is then checked. The legal result
> is saved to 'ioc'. Then, in condition MPT3COMMAND, the whole struct is
> fetched again from the userspace. Then _ctl_do_mpt_command() is called,
> 'ioc' and 'karg' as inputs.
>
> However, a malicious user can change the 'ioc_number' between the two
> fetches, which will cause a potential security issues.  Moreover, a
> malicious user can provide a valid 'ioc_number' to pass the check in
> first fetch, and then modify it in the second fetch.
>
> To fix this, we need to recheck the 'ioc_number' in the second fetch.
>
> Signed-off-by: Gen Zhang 
> ---
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c 
> b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> index b2bb47c..5181c03 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> @@ -2319,6 +2319,10 @@ _ctl_ioctl_main(struct file *file, unsigned int cmd, 
> void __user *arg,
> break;
> }
>
> +   if (karg.hdr.ioc_number != ioctl_header.ioc_number) {
> +   ret = -EINVAL;
> +   break;
> +   }
> if (_IOC_SIZE(cmd) == sizeof(struct mpt3_ioctl_command)) {
> uarg = arg;
> ret = _ctl_do_mpt_command(ioc, karg, &uarg->mf);