| Message ID | 1528453593-225313-1-git-send-email-john.garry@huawei.com |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
| Series | libahci: Fix possible Spectre-v1 pmp indexing in ahci_led_store() | expand |
On Fri, Jun 08, 2018 at 06:26:33PM +0800, John Garry wrote: > Currently smatch warns of possible Spectre-V1 issue in ahci_led_store(): > drivers/ata/libahci.c:1150 ahci_led_store() warn: potential spectre issue 'pp->em_priv' (local cap) > > Userspace controls @pmp from following callchain: > em_message->store() > ->ata_scsi_em_message_store() > -->ap->ops->em_store() > --->ahci_led_store() > > After the mask+shift @pmp is effectively an 8b value, which is used to > index into an array of length 8, so sanitize the array index. > > Signed-off-by: John Garry <john.garry@huawei.com> Applied to libata/for-4.18-fixes. Thanks.
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 7adcf3c..4ce5bb4 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -35,6 +35,7 @@ #include <linux/kernel.h> #include <linux/gfp.h> #include <linux/module.h> +#include <linux/nospec.h> #include <linux/blkdev.h> #include <linux/delay.h> #include <linux/interrupt.h> @@ -1142,10 +1143,12 @@ static ssize_t ahci_led_store(struct ata_port *ap, const char *buf, /* get the slot number from the message */ pmp = (state & EM_MSG_LED_PMP_SLOT) >> 8; - if (pmp < EM_MAX_SLOTS) + if (pmp < EM_MAX_SLOTS) { + pmp = array_index_nospec(pmp, EM_MAX_SLOTS); emp = &pp->em_priv[pmp]; - else + } else { return -EINVAL; + } /* mask off the activity bits if we are in sw_activity * mode, user should turn off sw_activity before setting
Currently smatch warns of possible Spectre-V1 issue in ahci_led_store(): drivers/ata/libahci.c:1150 ahci_led_store() warn: potential spectre issue 'pp->em_priv' (local cap) Userspace controls @pmp from following callchain: em_message->store() ->ata_scsi_em_message_store() -->ap->ops->em_store() --->ahci_led_store() After the mask+shift @pmp is effectively an 8b value, which is used to index into an array of length 8, so sanitize the array index. Signed-off-by: John Garry <john.garry@huawei.com>