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| author | Wenwen Wang <wang6495@umn.edu> | 2018-10-06 21:34:21 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2018-10-17 00:55:20 +0300 |
| commit | 47db7873136a9c57c45390a53b57019cf73c8259 (patch) | |
| tree | cc2c5aea86971daedff531b0a9b9803abd48c92e /drivers/scsi/megaraid | |
| parent | fd13f0517d2f99cfac6a82fe4654aa62ec14284c (diff) | |
| download | linux-47db7873136a9c57c45390a53b57019cf73c8259.tar.xz | |
scsi: megaraid_sas: fix a missing-check bug
In megasas_mgmt_compat_ioctl_fw(), to handle the structure
compat_megasas_iocpacket 'cioc', a user-space structure megasas_iocpacket
'ioc' is allocated before megasas_mgmt_ioctl_fw() is invoked to handle
the packet. Since the two data structures have different fields, the data
is copied from 'cioc' to 'ioc' field by field. In the copy process,
'sense_ptr' is prepared if the field 'sense_len' is not null, because it
will be used in megasas_mgmt_ioctl_fw(). To prepare 'sense_ptr', the
user-space data 'ioc->sense_off' and 'cioc->sense_off' are copied and
saved to kernel-space variables 'local_sense_off' and 'user_sense_off'
respectively. Given that 'ioc->sense_off' is also copied from
'cioc->sense_off', 'local_sense_off' and 'user_sense_off' should have the
same value. However, 'cioc' is in the user space and a malicious user can
race to change the value of 'cioc->sense_off' after it is copied to
'ioc->sense_off' but before it is copied to 'user_sense_off'. By doing
so, the attacker can inject different values into 'local_sense_off' and
'user_sense_off'. This can cause undefined behavior in the following
execution, because the two variables are supposed to be same.
This patch enforces a check on the two kernel variables 'local_sense_off'
and 'user_sense_off' to make sure they are the same after the copy. In
case they are not, an error code EINVAL will be returned.
Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Acked-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/megaraid')
| -rw-r--r-- | drivers/scsi/megaraid/megaraid_sas_base.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c index 9aa9590c5373..f6de7526ded5 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -7523,6 +7523,9 @@ static int megasas_mgmt_compat_ioctl_fw(struct file *file, unsigned long arg) get_user(user_sense_off, &cioc->sense_off)) return -EFAULT; + if (local_sense_off != user_sense_off) + return -EINVAL; + if (local_sense_len) { void __user **sense_ioc_ptr = (void __user **)((u8 *)((unsigned long)&ioc->frame.raw) + local_sense_off); |