From: Wenwen Wang Date: Sat, 6 Oct 2018 18:34:21 +0000 (-0500) Subject: scsi: megaraid_sas: fix a missing-check bug X-Git-Tag: Ubuntu-4.15.0-56.62~947 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=74088c7edc1bc78fe5fb1bb6535cff1899d5c799;p=mirror_ubuntu-bionic-kernel.git scsi: megaraid_sas: fix a missing-check bug BugLink: https://bugs.launchpad.net/bugs/1836802 [ 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 Acked-by: Sumit Saxena Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andrea Righi Signed-off-by: Khalid Elmously --- diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c index 305ccbaf3586..82052598ec9e 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -7530,6 +7530,9 @@ 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);