Re: [PATCH 001/190] Revert "net/rds: Avoid potential use after free in rds_send_remove_from_sock"

[Greg Kroah-Hartman]

On Wed, Apr 21, 2021 at 02:57:56PM +0200, Greg Kroah-Hartman wrote:
> This reverts commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05.
> 
> Commits from @umn.edu addresses have been found to be submitted in "bad
> faith" to try to test the kernel community's ability to review "known
> malicious" changes.  The result of these submissions can be found in a
> paper published at the 42nd IEEE Symposium on Security and Privacy
> entitled, "Open Source Insecurity: Stealthily Introducing
> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> of Minnesota) and Kangjie Lu (University of Minnesota).
> 
> Because of this, all submissions from this group must be reverted from
> the kernel tree and will need to be re-reviewed again to determine if
> they actually are a valid fix.  Until that work is complete, remove this
> change to ensure that no problems are being introduced into the
> codebase.
> 
> Cc: Aditya Pakki <pakki001@xxxxxxx>
> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
> Cc: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  net/rds/message.c | 1 -
>  net/rds/send.c    | 2 +-
>  2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/net/rds/message.c b/net/rds/message.c
> index 4fc66ff0f1ec..799034e0f513 100644
> --- a/net/rds/message.c
> +++ b/net/rds/message.c
> @@ -180,7 +180,6 @@ void rds_message_put(struct rds_message *rm)
>  		rds_message_purge(rm);
>  
>  		kfree(rm);
> -		rm = NULL;
>  	}
>  }
>  EXPORT_SYMBOL_GPL(rds_message_put);
> diff --git a/net/rds/send.c b/net/rds/send.c
> index fe5264b9d4b3..985d0b7713ac 100644
> --- a/net/rds/send.c
> +++ b/net/rds/send.c
> @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status)
>  unlock_and_drop:
>  		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
>  		rds_message_put(rm);
> -		if (was_on_sock && rm)
> +		if (was_on_sock)
>  			rds_message_put(rm);
>  	}
>  
> -- 
> 2.31.1
> 

The original, while again messy, looks ok, so I'll drop this revert.

greg k-h