Revision 9c1c2b35f1d94de8325344c2777d7ee67492db3b authored by Jeff Layton on 03 April 2019, 17:16:01 UTC, committed by Ilya Dryomov on 21 January 2020, 18:02:37 UTC
Currently, we just assume that it will stick around by virtue of the submitter's reference, but later patches will allow the syscall to return early and we can't rely on that reference at that point. While I'm not aware of any reports of it, Xiubo pointed out that this may fix a use-after-free. If the wait for a reply times out or is canceled via signal, and then the reply comes in after the syscall returns, the client can end up trying to access r_parent without a reference. Take an extra reference to the inode when setting r_parent and release it when releasing the request. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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sp-dev.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* AMD Secure Processor driver
*
* Copyright (C) 2017-2018 Advanced Micro Devices, Inc.
*
* Author: Tom Lendacky <thomas.lendacky@amd.com>
* Author: Gary R Hook <gary.hook@amd.com>
* Author: Brijesh Singh <brijesh.singh@amd.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/spinlock_types.h>
#include <linux/types.h>
#include <linux/ccp.h>
#include "ccp-dev.h"
#include "sp-dev.h"
MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
MODULE_AUTHOR("Gary R Hook <gary.hook@amd.com>");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.1.0");
MODULE_DESCRIPTION("AMD Secure Processor driver");
/* List of SPs, SP count, read-write access lock, and access functions
*
* Lock structure: get sp_unit_lock for reading whenever we need to
* examine the SP list.
*/
static DEFINE_RWLOCK(sp_unit_lock);
static LIST_HEAD(sp_units);
/* Ever-increasing value to produce unique unit numbers */
static atomic_t sp_ordinal;
static void sp_add_device(struct sp_device *sp)
{
unsigned long flags;
write_lock_irqsave(&sp_unit_lock, flags);
list_add_tail(&sp->entry, &sp_units);
write_unlock_irqrestore(&sp_unit_lock, flags);
}
static void sp_del_device(struct sp_device *sp)
{
unsigned long flags;
write_lock_irqsave(&sp_unit_lock, flags);
list_del(&sp->entry);
write_unlock_irqrestore(&sp_unit_lock, flags);
}
static irqreturn_t sp_irq_handler(int irq, void *data)
{
struct sp_device *sp = data;
if (sp->ccp_irq_handler)
sp->ccp_irq_handler(irq, sp->ccp_irq_data);
if (sp->psp_irq_handler)
sp->psp_irq_handler(irq, sp->psp_irq_data);
return IRQ_HANDLED;
}
int sp_request_ccp_irq(struct sp_device *sp, irq_handler_t handler,
const char *name, void *data)
{
int ret;
if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->psp_vdata) {
/* Need a common routine to manage all interrupts */
sp->ccp_irq_data = data;
sp->ccp_irq_handler = handler;
if (!sp->irq_registered) {
ret = request_irq(sp->ccp_irq, sp_irq_handler, 0,
sp->name, sp);
if (ret)
return ret;
sp->irq_registered = true;
}
} else {
/* Each sub-device can manage it's own interrupt */
ret = request_irq(sp->ccp_irq, handler, 0, name, data);
if (ret)
return ret;
}
return 0;
}
int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
const char *name, void *data)
{
int ret;
if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->ccp_vdata) {
/* Need a common routine to manage all interrupts */
sp->psp_irq_data = data;
sp->psp_irq_handler = handler;
if (!sp->irq_registered) {
ret = request_irq(sp->psp_irq, sp_irq_handler, 0,
sp->name, sp);
if (ret)
return ret;
sp->irq_registered = true;
}
} else {
/* Each sub-device can manage it's own interrupt */
ret = request_irq(sp->psp_irq, handler, 0, name, data);
if (ret)
return ret;
}
return 0;
}
void sp_free_ccp_irq(struct sp_device *sp, void *data)
{
if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->psp_vdata) {
/* Using common routine to manage all interrupts */
if (!sp->psp_irq_handler) {
/* Nothing else using it, so free it */
free_irq(sp->ccp_irq, sp);
sp->irq_registered = false;
}
sp->ccp_irq_handler = NULL;
sp->ccp_irq_data = NULL;
} else {
/* Each sub-device can manage it's own interrupt */
free_irq(sp->ccp_irq, data);
}
}
void sp_free_psp_irq(struct sp_device *sp, void *data)
{
if ((sp->psp_irq == sp->ccp_irq) && sp->dev_vdata->ccp_vdata) {
/* Using common routine to manage all interrupts */
if (!sp->ccp_irq_handler) {
/* Nothing else using it, so free it */
free_irq(sp->psp_irq, sp);
sp->irq_registered = false;
}
sp->psp_irq_handler = NULL;
sp->psp_irq_data = NULL;
} else {
/* Each sub-device can manage it's own interrupt */
free_irq(sp->psp_irq, data);
}
}
/**
* sp_alloc_struct - allocate and initialize the sp_device struct
*
* @dev: device struct of the SP
*/
struct sp_device *sp_alloc_struct(struct device *dev)
{
struct sp_device *sp;
sp = devm_kzalloc(dev, sizeof(*sp), GFP_KERNEL);
if (!sp)
return NULL;
sp->dev = dev;
sp->ord = atomic_inc_return(&sp_ordinal);
snprintf(sp->name, SP_MAX_NAME_LEN, "sp-%u", sp->ord);
return sp;
}
int sp_init(struct sp_device *sp)
{
sp_add_device(sp);
if (sp->dev_vdata->ccp_vdata)
ccp_dev_init(sp);
if (sp->dev_vdata->psp_vdata)
psp_dev_init(sp);
return 0;
}
void sp_destroy(struct sp_device *sp)
{
if (sp->dev_vdata->ccp_vdata)
ccp_dev_destroy(sp);
if (sp->dev_vdata->psp_vdata)
psp_dev_destroy(sp);
sp_del_device(sp);
}
#ifdef CONFIG_PM
int sp_suspend(struct sp_device *sp, pm_message_t state)
{
int ret;
if (sp->dev_vdata->ccp_vdata) {
ret = ccp_dev_suspend(sp, state);
if (ret)
return ret;
}
return 0;
}
int sp_resume(struct sp_device *sp)
{
int ret;
if (sp->dev_vdata->ccp_vdata) {
ret = ccp_dev_resume(sp);
if (ret)
return ret;
}
return 0;
}
#endif
struct sp_device *sp_get_psp_master_device(void)
{
struct sp_device *i, *ret = NULL;
unsigned long flags;
write_lock_irqsave(&sp_unit_lock, flags);
if (list_empty(&sp_units))
goto unlock;
list_for_each_entry(i, &sp_units, entry) {
if (i->psp_data && i->get_psp_master_device) {
ret = i->get_psp_master_device();
break;
}
}
unlock:
write_unlock_irqrestore(&sp_unit_lock, flags);
return ret;
}
static int __init sp_mod_init(void)
{
#ifdef CONFIG_X86
int ret;
ret = sp_pci_init();
if (ret)
return ret;
#ifdef CONFIG_CRYPTO_DEV_SP_PSP
psp_pci_init();
#endif
return 0;
#endif
#ifdef CONFIG_ARM64
int ret;
ret = sp_platform_init();
if (ret)
return ret;
return 0;
#endif
return -ENODEV;
}
static void __exit sp_mod_exit(void)
{
#ifdef CONFIG_X86
#ifdef CONFIG_CRYPTO_DEV_SP_PSP
psp_pci_exit();
#endif
sp_pci_exit();
#endif
#ifdef CONFIG_ARM64
sp_platform_exit();
#endif
}
module_init(sp_mod_init);
module_exit(sp_mod_exit);
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