From: Gen Zhang Date: Thu, 30 May 2019 09:10:30 +0800 Subject: scsi: mpt3sas_ctl: fix double-fetch bug in _ctl_ioctl_main() Git-commit: f9e3ebeea4521652318af903cddeaf033527e93e Patch-mainline: v5.3-rc1 References: bsc#1136922 CVE-2019-12456 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 Acked-by: Suganath Prabu S Signed-off-by: Martin K. Petersen Acked-by: Lee Duncan --- drivers/scsi/mpt3sas/mpt3sas_ctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c index b2bb47c14d35..5181c03e82a6 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);