fix #5448: support SCSI contollers with bad VDP page length encoding again

The reporter has an Adaptec 5805 controller (using the aacraid
driver), which reports a byteswapped page length for VPD page 0. It
reports "02 00" as page length instead of "00 02".

This stopped working with kernel 6.8.4 due to commit b5fc07a5fb56
("scsi: core: Consult supported VPD page list prior to fetching page")

To address that issue limit the page search scope to the size of our
VPD buffer to guard against devices returning a larger page count than
requested.

Reported-by: Peter Schneider <pschneider1968@googlemail.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
This commit is contained in:
Thomas Lamprecht 2024-06-20 10:54:47 +02:00
parent 8b2b863fa7
commit 77af8d24c4

View File

@ -0,0 +1,49 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Mon, 20 May 2024 22:30:40 -0400
Subject: [PATCH] scsi: core: Handle devices which return an unusually large
VPD page count
Peter Schneider reported that a system would no longer boot after
updating to 6.8.4. Peter bisected the issue and identified commit
b5fc07a5fb56 ("scsi: core: Consult supported VPD page list prior to
fetching page") as being the culprit.
Turns out the enclosure device in Peter's system reports a byteswapped
page length for VPD page 0. It reports "02 00" as page length instead
of "00 02". This causes us to attempt to access 516 bytes (page length
+ header) of information despite only 2 pages being present.
Limit the page search scope to the size of our VPD buffer to guard
against devices returning a larger page count than requested.
Link: https://lore.kernel.org/r/20240521023040.2703884-1-martin.petersen@oracle.com
Fixes: b5fc07a5fb56 ("scsi: core: Consult supported VPD page list prior to fetching page")
Cc: stable@vger.kernel.org
Reported-by: Peter Schneider <pschneider1968@googlemail.com>
Closes: https://lore.kernel.org/all/eec6ebbf-061b-4a7b-96dc-ea748aa4d035@googlemail.com/
Tested-by: Peter Schneider <pschneider1968@googlemail.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
drivers/scsi/scsi.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 8cad9792a562..b3ff3a633a1e 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -350,6 +350,13 @@ static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
if (result < SCSI_VPD_HEADER_SIZE)
return 0;
+ if (result > sizeof(vpd)) {
+ dev_warn_once(&sdev->sdev_gendev,
+ "%s: long VPD page 0 length: %d bytes\n",
+ __func__, result);
+ result = sizeof(vpd);
+ }
+
result -= SCSI_VPD_HEADER_SIZE;
if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
return 0;