From fae2a63737e5973f1426bc139935a0f42e232844 Mon Sep 17 00:00:00 2001 From: John Garry Date: Fri, 8 Jun 2018 18:26:33 +0800 Subject: [PATCH] libahci: Fix possible Spectre-v1 pmp indexing in ahci_led_store() 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 Signed-off-by: Tejun Heo --- drivers/ata/libahci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c index 965842a08743..09620c2ffa0f 100644 --- a/drivers/ata/libahci.c +++ b/drivers/ata/libahci.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -1146,10 +1147,12 @@ 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