| Message ID | 20240521023040.2703884-1-martin.petersen@oracle.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | scsi: core: Handle devices which return an unusually large VPD page count | expand |
Am 21.05.2024 um 04:30 schrieb Martin K. Petersen: > 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. > > Cc: stable@vger.kernel.org > Reported-by: Peter Schneider <pschneider1968@googlemail.com> > Tested-by: Peter Schneider <pschneider1968@googlemail.com> > Fixes: b5fc07a5fb56 ("scsi: core: Consult supported VPD page list prior to fetching page") > Link: https://lore.kernel.org/all/eec6ebbf-061b-4a7b-96dc-ea748aa4d035@googlemail.com/ > 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 3e0c0381277a..f0464db3f9de 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; I have built and tested Martin's patch against 6.8.4, 6.8.10, and 6.9.1, and it works fine and fixes my issue. Tested-by: Peter Schneider <pschneider1968@googlemail.com> In case anybody else is affected: The enclosure device in question with that buggy behaviour is that in a Supermicro 745BTQ-R920B server casing, with SAS/SATA Backplane "743 SAS BACKPLANE W/AMI MG9072", MG9072 being the controller chip by American Megatrends, Inc. according to the device documentation which can be found here: https://www.supermicro.com/de/products/chassis/4u/745/sc745btq-r920b Beste Grüße, Peter Schneider
On 5/20/24 19:30, Martin K. Petersen wrote: > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index 3e0c0381277a..f0464db3f9de 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; Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 3e0c0381277a..f0464db3f9de 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;
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. Cc: stable@vger.kernel.org Reported-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Fixes: b5fc07a5fb56 ("scsi: core: Consult supported VPD page list prior to fetching page") Link: https://lore.kernel.org/all/eec6ebbf-061b-4a7b-96dc-ea748aa4d035@googlemail.com/ Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> --- drivers/scsi/scsi.c | 7 +++++++ 1 file changed, 7 insertions(+)