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Date:   Tue, 3 Oct 2023 10:10:41 +0100
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Lukas Wunner <lukas@wunner.de>
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Subject: Re: [PATCH 04/12] certs: Create blacklist keyring earlier
Message-ID: <20231003101041.00006511@Huawei.com>
In-Reply-To: <3db7a8856833dfcbc4b122301f233828379d67db.1695921657.git.lukas@wunner.de>
References: <cover.1695921656.git.lukas@wunner.de>
        <3db7a8856833dfcbc4b122301f233828379d67db.1695921657.git.lukas@wunner.de>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Thu, 28 Sep 2023 19:32:32 +0200
Lukas Wunner <lukas@wunner.de> wrote:

> The upcoming support for PCI device authentication with CMA-SPDM
> (PCIe r6.1 sec 6.31) requires parsing X.509 certificates upon
> device enumeration, which happens in a subsys_initcall().
> 
> Parsing X.509 certificates accesses the blacklist keyring:
> x509_cert_parse()
>   x509_get_sig_params()
>     is_hash_blacklisted()
>       keyring_search()
> 
> So far the keyring is created much later in a device_initcall().  Avoid
> a NULL pointer dereference on access to the keyring by creating it one
> initcall level earlier than PCI device enumeration, i.e. in an
> arch_initcall().
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
Indeed seems like it needs to be before subsys_initcall so whilst
it feels a bit weird to do it in one named arch, I guess that's the best choice
available.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  certs/blacklist.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/certs/blacklist.c b/certs/blacklist.c
> index 675dd7a8f07a..34185415d451 100644
> --- a/certs/blacklist.c
> +++ b/certs/blacklist.c
> @@ -311,7 +311,7 @@ static int restrict_link_for_blacklist(struct key *dest_keyring,
>   * Initialise the blacklist
>   *
>   * The blacklist_init() function is registered as an initcall via
> - * device_initcall().  As a result if the blacklist_init() function fails for
> + * arch_initcall().  As a result if the blacklist_init() function fails for
>   * any reason the kernel continues to execute.  While cleanly returning -ENODEV
>   * could be acceptable for some non-critical kernel parts, if the blacklist
>   * keyring fails to load it defeats the certificate/key based deny list for
> @@ -356,7 +356,7 @@ static int __init blacklist_init(void)
>  /*
>   * Must be initialised before we try and load the keys into the keyring.
>   */
> -device_initcall(blacklist_init);
> +arch_initcall(blacklist_init);
>  
>  #ifdef CONFIG_SYSTEM_REVOCATION_LIST
>  /*