libahci: Fix possible Spectre-v1 pmp indexing in ahci_led_store()
[ Upstream commit fae2a63737
]
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>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
ed4afe79ba
commit
7ccd2c1be3
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@ -35,6 +35,7 @@
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#include <linux/kernel.h>
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#include <linux/gfp.h>
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#include <linux/module.h>
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#include <linux/nospec.h>
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#include <linux/blkdev.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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@ -1135,10 +1136,12 @@ static ssize_t ahci_led_store(struct ata_port *ap, const char *buf,
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/* get the slot number from the message */
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pmp = (state & EM_MSG_LED_PMP_SLOT) >> 8;
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if (pmp < EM_MAX_SLOTS)
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if (pmp < EM_MAX_SLOTS) {
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pmp = array_index_nospec(pmp, EM_MAX_SLOTS);
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emp = &pp->em_priv[pmp];
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else
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} else {
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return -EINVAL;
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}
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/* mask off the activity bits if we are in sw_activity
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* mode, user should turn off sw_activity before setting
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