I've never backported a linux patch before; so I'm not sure if this is the right format. However, this cleanly applies to the linux-4.9.y branch. This is a backport of commit 817aef260037f33ee0f44c17fe341323d3aebd6d.

---------------------------- Signed-off-by: Yannik Sembritzki yannik@sembritzki.me Cc: stable@vger.kernel.org ---  certs/system_keyring.c                  |    3 ++-  crypto/asymmetric_keys/pkcs7_key_type.c |    2 +-  include/linux/verification.h            |    6 ++++++  3 files changed, 9 insertions(+), 2 deletions(-)

--- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -15,5 +15,6 @@  #include <linux/cred.h>  #include <linux/err.h> +#include <linux/verification.h>  #include <keys/asymmetric-type.h>  #include <keys/system_keyring.h>  #include <crypto/pkcs7.h> @@ -230,7 +231,7 @@ int verify_pkcs7_signature(const void *d        if (!trusted_keys) {          trusted_keys = builtin_trusted_keys; -    } else if (trusted_keys == (void *)1UL) { +    } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {  #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING          trusted_keys = secondary_trusted_keys;  #else --- a/crypto/asymmetric_keys/pkcs7_key_type.c +++ b/crypto/asymmetric_keys/pkcs7_key_type.c @@ -63,7 +63,7 @@ static int pkcs7_preparse(struct key_pre        return verify_pkcs7_signature(NULL, 0,                        prep->data, prep->datalen, -                      (void *)1UL, usage, +                      VERIFY_USE_SECONDARY_KEYRING, usage,                        pkcs7_view_content, prep);  }   --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -13,6 +13,12 @@  #define _LINUX_VERIFICATION_H    /* + * Indicate that both builtin trusted keys and secondary trusted keys + * should be used. + */ +#define VERIFY_USE_SECONDARY_KEYRING ((struct key *)1UL) + +/*   * The use to which an asymmetric key is being put.   */  enum key_being_used_for {

On 07.09.2018 11:13, gregkh@linuxfoundation.org wrote:

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 817aef260037f33ee0f44c17fe341323d3aebd6d Mon Sep 17 00:00:00 2001 From: Yannik Sembritzki yannik@sembritzki.me Date: Thu, 16 Aug 2018 14:05:10 +0100 Subject: [PATCH] Replace magic for trusting the secondary keyring with #define

Replace the use of a magic number that indicates that verify_*_signature() should use the secondary keyring with a symbol.

Signed-off-by: Yannik Sembritzki yannik@sembritzki.me Signed-off-by: David Howells dhowells@redhat.com Cc: keyrings@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org

diff --git a/certs/system_keyring.c b/certs/system_keyring.c index 6251d1b27f0c..81728717523d 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -15,6 +15,7 @@ #include <linux/cred.h> #include <linux/err.h> #include <linux/slab.h> +#include <linux/verification.h> #include <keys/asymmetric-type.h> #include <keys/system_keyring.h> #include <crypto/pkcs7.h> @@ -230,7 +231,7 @@ int verify_pkcs7_signature(const void *data, size_t len, if (!trusted_keys) { trusted_keys = builtin_trusted_keys;

• } else if (trusted_keys == (void *)1UL) {

• } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {

#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING trusted_keys = secondary_trusted_keys; #else diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c b/crypto/asymmetric_keys/pkcs7_key_type.c index e284d9cb9237..5b2f6a2b5585 100644 --- a/crypto/asymmetric_keys/pkcs7_key_type.c +++ b/crypto/asymmetric_keys/pkcs7_key_type.c @@ -63,7 +63,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep) return verify_pkcs7_signature(NULL, 0, prep->data, prep->datalen,

• 		      (void *)1UL, usage,
  

• 		      VERIFY_USE_SECONDARY_KEYRING, usage,
  	      pkcs7_view_content, prep);
  

} diff --git a/include/linux/verification.h b/include/linux/verification.h index a10549a6c7cd..cfa4730d607a 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -12,6 +12,12 @@ #ifndef _LINUX_VERIFICATION_H #define _LINUX_VERIFICATION_H +/*

• • Indicate that both builtin trusted keys and secondary trusted keys
• • should be used.
• */

+#define VERIFY_USE_SECONDARY_KEYRING ((struct key *)1UL)

/*

• The use to which an asymmetric key is being put.

*/