OpenCloudOS-Kernel/drivers/infiniband/hw/hfi1/mmu_rb.h

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/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
/*
IB/hfi1: Ensure correct mm is used at all times Two earlier bug fixes have created a security problem in the hfi1 driver. One fix aimed to solve an issue where current->mm was not valid when closing the hfi1 cdev. It attempted to do this by saving a cached value of the current->mm pointer at file open time. This is a problem if another process with access to the FD calls in via write() or ioctl() to pin pages via the hfi driver. The other fix tried to solve a use after free by taking a reference on the mm. To fix this correctly we use the existing cached value of the mm in the mmu notifier. Now we can check in the insert, evict, etc. routines that current->mm matched what the notifier was registered for. If not, then don't allow access. The register of the mmu notifier will save the mm pointer. Since in do_exit() the exit_mm() is called before exit_files(), which would call our close routine a reference is needed on the mm. We rely on the mmgrab done by the registration of the notifier, whereas before it was explicit. The mmu notifier deregistration happens when the user context is torn down, the creation of which triggered the registration. Also of note is we do not do any explicit work to protect the interval tree notifier. It doesn't seem that this is going to be needed since we aren't actually doing anything with current->mm. The interval tree notifier stuff still has a FIXME noted from a previous commit that will be addressed in a follow on patch. Cc: <stable@vger.kernel.org> Fixes: e0cf75deab81 ("IB/hfi1: Fix mm_struct use after free") Fixes: 3faa3d9a308e ("IB/hfi1: Make use of mm consistent") Link: https://lore.kernel.org/r/20201125210112.104301.51331.stgit@awfm-01.aw.intel.com Suggested-by: Jann Horn <jannh@google.com> Reported-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2020-11-26 05:01:12 +08:00
* Copyright(c) 2020 Cornelis Networks, Inc.
* Copyright(c) 2016 Intel Corporation.
*/
#ifndef _HFI1_MMU_RB_H
#define _HFI1_MMU_RB_H
#include "hfi.h"
struct mmu_rb_node {
unsigned long addr;
unsigned long len;
unsigned long __last;
struct rb_node node;
IB/hfi1: Ensure correct mm is used at all times Two earlier bug fixes have created a security problem in the hfi1 driver. One fix aimed to solve an issue where current->mm was not valid when closing the hfi1 cdev. It attempted to do this by saving a cached value of the current->mm pointer at file open time. This is a problem if another process with access to the FD calls in via write() or ioctl() to pin pages via the hfi driver. The other fix tried to solve a use after free by taking a reference on the mm. To fix this correctly we use the existing cached value of the mm in the mmu notifier. Now we can check in the insert, evict, etc. routines that current->mm matched what the notifier was registered for. If not, then don't allow access. The register of the mmu notifier will save the mm pointer. Since in do_exit() the exit_mm() is called before exit_files(), which would call our close routine a reference is needed on the mm. We rely on the mmgrab done by the registration of the notifier, whereas before it was explicit. The mmu notifier deregistration happens when the user context is torn down, the creation of which triggered the registration. Also of note is we do not do any explicit work to protect the interval tree notifier. It doesn't seem that this is going to be needed since we aren't actually doing anything with current->mm. The interval tree notifier stuff still has a FIXME noted from a previous commit that will be addressed in a follow on patch. Cc: <stable@vger.kernel.org> Fixes: e0cf75deab81 ("IB/hfi1: Fix mm_struct use after free") Fixes: 3faa3d9a308e ("IB/hfi1: Make use of mm consistent") Link: https://lore.kernel.org/r/20201125210112.104301.51331.stgit@awfm-01.aw.intel.com Suggested-by: Jann Horn <jannh@google.com> Reported-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2020-11-26 05:01:12 +08:00
struct mmu_rb_handler *handler;
struct list_head list;
};
/*
* NOTE: filter, insert, invalidate, and evict must not sleep. Only remove is
* allowed to sleep.
*/
struct mmu_rb_ops {
bool (*filter)(struct mmu_rb_node *node, unsigned long addr,
unsigned long len);
int (*insert)(void *ops_arg, struct mmu_rb_node *mnode);
void (*remove)(void *ops_arg, struct mmu_rb_node *mnode);
int (*invalidate)(void *ops_arg, struct mmu_rb_node *node);
int (*evict)(void *ops_arg, struct mmu_rb_node *mnode,
void *evict_arg, bool *stop);
};
IB/hfi1: Ensure correct mm is used at all times Two earlier bug fixes have created a security problem in the hfi1 driver. One fix aimed to solve an issue where current->mm was not valid when closing the hfi1 cdev. It attempted to do this by saving a cached value of the current->mm pointer at file open time. This is a problem if another process with access to the FD calls in via write() or ioctl() to pin pages via the hfi driver. The other fix tried to solve a use after free by taking a reference on the mm. To fix this correctly we use the existing cached value of the mm in the mmu notifier. Now we can check in the insert, evict, etc. routines that current->mm matched what the notifier was registered for. If not, then don't allow access. The register of the mmu notifier will save the mm pointer. Since in do_exit() the exit_mm() is called before exit_files(), which would call our close routine a reference is needed on the mm. We rely on the mmgrab done by the registration of the notifier, whereas before it was explicit. The mmu notifier deregistration happens when the user context is torn down, the creation of which triggered the registration. Also of note is we do not do any explicit work to protect the interval tree notifier. It doesn't seem that this is going to be needed since we aren't actually doing anything with current->mm. The interval tree notifier stuff still has a FIXME noted from a previous commit that will be addressed in a follow on patch. Cc: <stable@vger.kernel.org> Fixes: e0cf75deab81 ("IB/hfi1: Fix mm_struct use after free") Fixes: 3faa3d9a308e ("IB/hfi1: Make use of mm consistent") Link: https://lore.kernel.org/r/20201125210112.104301.51331.stgit@awfm-01.aw.intel.com Suggested-by: Jann Horn <jannh@google.com> Reported-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2020-11-26 05:01:12 +08:00
struct mmu_rb_handler {
struct mmu_notifier mn;
struct rb_root_cached root;
void *ops_arg;
spinlock_t lock; /* protect the RB tree */
struct mmu_rb_ops *ops;
struct list_head lru_list;
struct work_struct del_work;
struct list_head del_list;
struct workqueue_struct *wq;
};
int hfi1_mmu_rb_register(void *ops_arg,
struct mmu_rb_ops *ops,
struct workqueue_struct *wq,
struct mmu_rb_handler **handler);
void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler);
int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
struct mmu_rb_node *mnode);
void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg);
void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler,
struct mmu_rb_node *mnode);
bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler,
unsigned long addr, unsigned long len,
struct mmu_rb_node **rb_node);
#endif /* _HFI1_MMU_RB_H */