scsi: mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main()

commit f9e3ebeea4521652318af903cddeaf033527e93e upstream.

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: NGen Zhang <blackgod016574@gmail.com>
Acked-by: NSuganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

drivers/scsi/mpt3sas/mpt3sas_ctl.c

@@ -2404,6 +2404,10 @@ _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);