| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 02/58] libata: array underflow in ata_find_dev() | Date | Wed, 9 Aug 2017 12:41:14 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
commit 59a5e266c3f5c1567508888dd61a45b86daed0fa upstream.
My static checker complains that "devno" can be negative, meaning that we read before the start of the loop. I've looked at the code, and I think the warning is right. This come from /proc so it's root only or it would be quite a quite a serious bug. The call tree looks like this:
proc_scsi_write() <- gets id and channel from simple_strtoul() -> scsi_add_single_device() <- calls shost->transportt->user_scan() -> ata_scsi_user_scan() -> ata_find_dev()
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/ata/libata-scsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2832,10 +2832,12 @@ static unsigned int atapi_xlat(struct at static struct ata_device *ata_find_dev(struct ata_port *ap, int devno) { if (!sata_pmp_attached(ap)) { - if (likely(devno < ata_link_max_devices(&ap->link))) + if (likely(devno >= 0 && + devno < ata_link_max_devices(&ap->link))) return &ap->link.device[devno]; } else { - if (likely(devno < ap->nr_pmp_links)) + if (likely(devno >= 0 && + devno < ap->nr_pmp_links)) return &ap->pmp_link[devno].device[0]; }
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