[PATCH AUTOSEL 4.19 172/191] scsi: NCR5380: Check for invalid reselection target

Sasha Levin
2019-11-10T03:08:06Z

From: Finn Thain <fthain@telegraphics.com.au>

[ Upstream commit 7ef55f6744c45e3d7c85a3f74ada39b67ac741dd ]

The X3T9.2 specification (draft) says, under "6.1.4.1 RESELECTION", that "the
initiator shall not respond to a RESELECTION phase if other than two SCSI ID
bits are on the DATA BUS." This issue (too many bits set) has been observed in
the wild, so add a check.

Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/NCR5380.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 90136942f4882..c67f476447372 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -2008,6 +2008,11 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
NCR5380_write(MODE_REG, MR_BASE);

target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
+ if (!target_mask || target_mask & (target_mask - 1)) {
+ shost_printk(KERN_WARNING, instance,
+ "reselect: bad target_mask 0x%02x\n", target_mask);
+ return;
+ }

dsprintk(NDEBUG_RESELECTION, instance, "reselect\n");

--
2.20.1