In _ctl_ioctl_main(), 'ioctl_header' is first copied from the userspace
pointer 'arg'. 'ioctl_header.ioc_number' is then verified by
_ctl_verify_adapter(). If the verification is failed, an error code -ENODEV
is returned. Otherwise, the verification result, i.e., the MPT3SAS adapter
that matches with the 'ioctl_header.ioc_number', is saved to 'ioc'. Later
on, if the 'cmd' is MPT3COMMAND, the whole ioctl command struct is copied
again from the userspace pointer 'arg' and saved to 'karg'. Then the
function _ctl_do_mpt_command() is invoked to execute the command with the
adapter 'ioc' and 'karg' as inputs.
Given that the pointer 'arg' resides in userspace, a malicious userspace
process can race to change the 'ioc_number' between the two copies, which
will cause inconsistency issues, potentially security issues since an
inconsistent adapter could be used with the command struct 'karg' as inputs
of _ctl_do_mpt_command(). Moreover, the user can potentially provide a
valid 'ioc_number' to pass the verification, and then modify it to an
invalid 'ioc_number'. That means, an invalid 'ioc_number' can potentially
bypass the verification check.
To fix this issue, we need to recheck the 'ioc_number' copied after the
second copy to make sure it is not changed since the first copy.
Signed-off-by: Wenwen Wang <[email protected]>
---
drivers/scsi/mpt3sas/mpt3sas_ctl.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index d3cb387..0c140c7 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -2388,6 +2388,11 @@ _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);
--
2.7.4
Hello
Could you please review this patch? We need a confirmation because we
are working on an approaching deadline.
Thanks!
Wenwen
On Sat, May 5, 2018 at 1:31 AM, Wenwen Wang <[email protected]> wrote:
> In _ctl_ioctl_main(), 'ioctl_header' is first copied from the userspace
> pointer 'arg'. 'ioctl_header.ioc_number' is then verified by
> _ctl_verify_adapter(). If the verification is failed, an error code -ENODEV
> is returned. Otherwise, the verification result, i.e., the MPT3SAS adapter
> that matches with the 'ioctl_header.ioc_number', is saved to 'ioc'. Later
> on, if the 'cmd' is MPT3COMMAND, the whole ioctl command struct is copied
> again from the userspace pointer 'arg' and saved to 'karg'. Then the
> function _ctl_do_mpt_command() is invoked to execute the command with the
> adapter 'ioc' and 'karg' as inputs.
>
> Given that the pointer 'arg' resides in userspace, a malicious userspace
> process can race to change the 'ioc_number' between the two copies, which
> will cause inconsistency issues, potentially security issues since an
> inconsistent adapter could be used with the command struct 'karg' as inputs
> of _ctl_do_mpt_command(). Moreover, the user can potentially provide a
> valid 'ioc_number' to pass the verification, and then modify it to an
> invalid 'ioc_number'. That means, an invalid 'ioc_number' can potentially
> bypass the verification check.
>
> To fix this issue, we need to recheck the 'ioc_number' copied after the
> second copy to make sure it is not changed since the first copy.
>
> Signed-off-by: Wenwen Wang <[email protected]>
> ---
> drivers/scsi/mpt3sas/mpt3sas_ctl.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> index d3cb387..0c140c7 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
> @@ -2388,6 +2388,11 @@ _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);
> --
> 2.7.4
>