Re: [PATCH] ila_xlat: add missing hash secret initialization

[David Miller <davem@davemloft.net>]

From: Arnd Bergmann <arnd@arndb.de>
Date: Thu,  8 Jun 2017 09:54:24 +0200

> While discussing the possible merits of clang warning about unused initialized
> functions, I found one function that was clearly meant to be called but
> never actually is.
> 
> __ila_hash_secret_init() initializes the hash value for the ila locator,
> apparently this is intended to prevent hash collision attacks, but this ends
> up being a read-only zero constant since there is no caller. I could find
> no indication of why it was never called, the earliest patch submission
> for the module already was like this. If my interpretation is right, we
> certainly want to backport the patch to stable kernels as well.
> 
> I considered adding it to the ila_xlat_init callback, but for best effect
> the random data is read as late as possible, just before it is first used.
> The underlying net_get_random_once() is already highly optimized to avoid
> overhead when called frequently.
> 
> Fixes: 7f00feaf1076 ("ila: Add generic ILA translation facility")
> Cc: stable@vger.kernel.org
> Link: https://www.spinics.net/lists/kernel/msg2527243.html
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Yikes, good catch, applied and queued up for -stable.