diff options
| author | Wenwen Wang <wang6495@umn.edu> | 2018-10-06 13:34:21 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-13 11:16:52 -0800 |
| commit | b18de4e8bdc55f461c03d51d91f2887254a9b1e6 (patch) | |
| tree | 734b5f83546f1b611d770dc23dac77d1e9df9340 | |
| parent | 57589690d423150d4464d86b2f2be60aff93804e (diff) | |
scsi: megaraid_sas: fix a missing-check bug
[ Upstream commit 47db7873136a9c57c45390a53b57019cf73c8259 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 090fdcdd15c9..5de024a50e15 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -6901,6 +6901,9 @@ 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); |