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

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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 <blackgod016574@gmail.com>
Acked-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Gen Zhang 2019-05-30 09:10:30 +08:00 committed by Martin K. Petersen
parent 8217444039
commit f9e3ebeea4
1 changed files with 4 additions and 0 deletions
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4
drivers/scsi/mpt3sas/mpt3sas_ctl.c
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@ -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);