From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gen Zhang Subject: [PATCH] mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main() Date: Thu, 30 May 2019 09:10:30 +0800 Message-ID: <20190530011030.GA6314@zhanggen-UX430UQ> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: sathya.prakash@broadcom.com, chaitra.basappa@broadcom.com, jejb@linux.ibm.com, martin.petersen@oracle.com Cc: suganath-prabu.subramani@broadcom.com, MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-scsi@vger.kernel.org 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 Ack-by: Suganath Prabu S --- 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);