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From: Ira Weiny <ira.weiny@intel.com>
To: dennis.dalessandro@cornelisnetworks.com
Cc: dledford@redhat.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org,
	Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH for-rc 4/4] IB/hfi1: Fix regressions in security fix
Date: Mon, 29 Mar 2021 11:36:09 -0700
Message-ID: <20210329183609.GA3014244@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <1617025700-31865-5-git-send-email-dennis.dalessandro@cornelisnetworks.com>

On Mon, Mar 29, 2021 at 09:48:20AM -0400, dennis.dalessandro@cornelisnetworks.com wrote:
> From: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
> 
> The security code guards for non-current mm in all cases for
> updating the rb tree.
> 
> That is ok for insert, but NOT ok for remove, since the insert
> has already guarded the node from being inserted and the remove
> can be called with a different mm because of a segfault other similar
> "close" issues where current-mm is NULL.
> 
> Best case, is we leak pages. worst case we delete items for an lru_list
> more than once:
> [20945.911107] list_del corruption, ffffa0cd536bcac8->next is LIST_POISON1 (dead000000000100)
> 
> Fix by removing the guard from any functions that remove nodes
> from the tree assuming the node was entered into the tree as valid since
> the insert is guarded.

Does this open up a child process being able to remove nodes which the parent
added?

Ira

> 
> Fixes: 3d2a9d642512 ("IB/hfi1: Ensure correct mm is used at all times")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
> ---
>  drivers/infiniband/hw/hfi1/mmu_rb.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/hfi1/mmu_rb.c b/drivers/infiniband/hw/hfi1/mmu_rb.c
> index f3fb28e..375a881 100644
> --- a/drivers/infiniband/hw/hfi1/mmu_rb.c
> +++ b/drivers/infiniband/hw/hfi1/mmu_rb.c
> @@ -210,9 +210,6 @@ bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler,
>  	unsigned long flags;
>  	bool ret = false;
>  
> -	if (current->mm != handler->mn.mm)
> -		return ret;
> -
>  	spin_lock_irqsave(&handler->lock, flags);
>  	node = __mmu_rb_search(handler, addr, len);
>  	if (node) {
> @@ -235,9 +232,6 @@ void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
>  	unsigned long flags;
>  	bool stop = false;
>  
> -	if (current->mm != handler->mn.mm)
> -		return;
> -
>  	INIT_LIST_HEAD(&del_list);
>  
>  	spin_lock_irqsave(&handler->lock, flags);
> @@ -271,9 +265,6 @@ void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler,
>  {
>  	unsigned long flags;
>  
> -	if (current->mm != handler->mn.mm)
> -		return;
> -
>  	/* Validity of handler and node pointers has been checked by caller. */
>  	trace_hfi1_mmu_rb_remove(node->addr, node->len);
>  	spin_lock_irqsave(&handler->lock, flags);
> -- 
> 1.8.3.1
> 

  reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-29 13:48 [PATCH for-rc 0/4] hfi fixes dennis.dalessandro
2021-03-29 13:48 ` [PATCH for-rc 1/4] IB/hfi1: Call xa_destroy before freeing dummy_netdev dennis.dalessandro
2021-03-29 14:09   ` Jason Gunthorpe
2021-03-31 19:36     ` Dennis Dalessandro
2021-04-01  6:06       ` Greg KH
2021-04-01 14:02         ` Dennis Dalessandro
2021-04-01 14:12           ` Greg KH
2021-04-01 15:00             ` Dennis Dalessandro
2021-04-01 12:33       ` Jason Gunthorpe
2021-04-01 13:42         ` Wan, Kaike
2021-04-01 13:48           ` Jason Gunthorpe
2021-03-29 13:48 ` [PATCH for-rc 2/4] IB/hfi1: Call xa_destroy before unloading the module dennis.dalessandro
2021-03-29 14:11   ` Jason Gunthorpe
2021-04-08 13:30     ` Dennis Dalessandro
2021-03-29 13:48 ` [PATCH for-rc 3/4] IB/hfi1: Fix probe time panic when AIP is enabled with a buggy BIOS dennis.dalessandro
2021-04-07 23:04   ` Jason Gunthorpe
2021-03-29 13:48 ` [PATCH for-rc 4/4] IB/hfi1: Fix regressions in security fix dennis.dalessandro
2021-03-29 18:36   ` Ira Weiny [this message]
2021-04-07 18:33     ` Jason Gunthorpe
2021-04-07 20:20       ` Dennis Dalessandro
2021-04-13 22:55   ` Jason Gunthorpe

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