Re: [PATCH 04/12] certs: Create blacklist keyring earlier

[Alistair Francis <Alistair.Francis@wdc.com>]

On Thu, 2023-09-28 at 19:32 +0200, Lukas Wunner 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>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  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
>  /*