RE: [PATCH] mpt3sas: Ensure the connector_name string is NUL-terminated

From: Chaitra Basappa
Date: Fri Aug 05 2016 - 02:48:14 EST


Hi,
Please consider this patch as Acked-by: Chaitra P B
<chaitra.basappa@xxxxxxxxxxxx>


Thanks,
Chaitra

-----Original Message-----
From: Calvin Owens [mailto:calvinowens@xxxxxx]
Sent: Thursday, July 28, 2016 10:16 AM
To: Sathya Prakash; Chaitra P B; Suganath Prabu Subramani; James E.J.
Bottomley; Martin K. Petersen
Cc: MPT-FusionLinux.pdl@xxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx;
linux-kernel@xxxxxxxxxxxxxxx; kernel-team@xxxxxx; Calvin Owens
Subject: [PATCH] mpt3sas: Ensure the connector_name string is
NUL-terminated

We blindly trust the hardware to give us NUL-terminated strings, which is
a bad idea because it doesn't always do that. For example:

[ 481.184784] mpt3sas_cm0: enclosure level(0x0000), connector name(
\x3)

In this case, connector_name is four spaces. We got lucky here because the
2nd byte beyond our character array happens to be a NUL. Fix this by
explicitly writing '\0' to the end of the string to ensure we don't run
off the edge of the world in printk().

Signed-off-by: Calvin Owens <calvinowens@xxxxxx>
---
drivers/scsi/mpt3sas/mpt3sas_base.h | 2 +-
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 10 ++++++----
2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h
b/drivers/scsi/mpt3sas/mpt3sas_base.h
index 892c9be..eb7f5b0 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -478,7 +478,7 @@ struct _sas_device {
u8 pfa_led_on;
u8 pend_sas_rphy_add;
u8 enclosure_level;
- u8 connector_name[4];
+ u8 connector_name[5];
struct kref refcount;
};

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index cd91a68..acabe48 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -5380,8 +5380,9 @@ _scsih_check_device(struct MPT3SAS_ADAPTER *ioc,
MPI2_SAS_DEVICE0_FLAGS_ENCL_LEVEL_VALID) {
sas_device->enclosure_level =

le16_to_cpu(sas_device_pg0.EnclosureLevel);
- memcpy(&sas_device->connector_name[0],
- &sas_device_pg0.ConnectorName[0], 4);
+ memcpy(sas_device->connector_name,
+ sas_device_pg0.ConnectorName, 4);
+ sas_device->connector_name[4] = '\0';
} else {
sas_device->enclosure_level = 0;
sas_device->connector_name[0] = '\0'; @@ -5508,8
+5509,9 @@ _scsih_add_device(struct MPT3SAS_ADAPTER *ioc, u16 handle, u8
phy_num,
if (sas_device_pg0.Flags &
MPI2_SAS_DEVICE0_FLAGS_ENCL_LEVEL_VALID) {
sas_device->enclosure_level =
le16_to_cpu(sas_device_pg0.EnclosureLevel);
- memcpy(&sas_device->connector_name[0],
- &sas_device_pg0.ConnectorName[0], 4);
+ memcpy(sas_device->connector_name,
+ sas_device_pg0.ConnectorName, 4);
+ sas_device->connector_name[4] = '\0';
} else {
sas_device->enclosure_level = 0;
sas_device->connector_name[0] = '\0';
--
2.8.0.rc2