linux/drivers/infiniband/hw/hfi1/user_exp_rcv.h
Dennis Dalessandro 3d2a9d6425 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: e0cf75deab ("IB/hfi1: Fix mm_struct use after free")
Fixes: 3faa3d9a30 ("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>
2020-11-25 20:30:46 -04:00

105 lines
3.5 KiB
C

#ifndef _HFI1_USER_EXP_RCV_H
#define _HFI1_USER_EXP_RCV_H
/*
* Copyright(c) 2020 - Cornelis Networks, Inc.
* Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* BSD LICENSE
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* modification, are permitted provided that the following conditions
* are met:
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* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/
#include "hfi.h"
#include "exp_rcv.h"
struct tid_pageset {
u16 idx;
u16 count;
};
struct tid_user_buf {
unsigned long vaddr;
unsigned long length;
unsigned int npages;
struct page **pages;
struct tid_pageset *psets;
unsigned int n_psets;
};
struct tid_rb_node {
struct mmu_interval_notifier notifier;
struct hfi1_filedata *fdata;
unsigned long phys;
struct tid_group *grp;
u32 rcventry;
dma_addr_t dma_addr;
bool freed;
unsigned int npages;
struct page *pages[];
};
static inline int num_user_pages(unsigned long addr,
unsigned long len)
{
const unsigned long spage = addr & PAGE_MASK;
const unsigned long epage = (addr + len - 1) & PAGE_MASK;
return 1 + ((epage - spage) >> PAGE_SHIFT);
}
int hfi1_user_exp_rcv_init(struct hfi1_filedata *fd,
struct hfi1_ctxtdata *uctxt);
void hfi1_user_exp_rcv_free(struct hfi1_filedata *fd);
int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
int hfi1_user_exp_rcv_clear(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
int hfi1_user_exp_rcv_invalid(struct hfi1_filedata *fd,
struct hfi1_tid_info *tinfo);
static inline struct mm_struct *mm_from_tid_node(struct tid_rb_node *node)
{
return node->notifier.mm;
}
#endif /* _HFI1_USER_EXP_RCV_H */