linux-kernel - [PATCH 2/2] Replace magic for trusting the secondary keyring with #define

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Date:   Wed, 15 Aug 2018 21:42:44 +0200
From:   Yannik Sembritzki <yannik@...britzki.me>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        David Howells <dhowells@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Peter Anvin <hpa@...or.com>,
        the arch/x86 maintainers <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
        "Justin M. Forbes" <jforbes@...hat.com>,
        Peter Jones <pjones@...hat.com>,
        James Bottomley <James.Bottomley@...senPartnership.com>,
        Matthew Garrett <mjg59@...gle.com>,
        Vivek Goyal <vgoyal@...hat.com>
Cc:     Yannik Sembritzki <yannik@...britzki.me>
Subject: [PATCH 2/2] Replace magic for trusting the secondary keyring with #define

Signed-off-by: Yannik Sembritzki <yannik@...britzki.me>
---
 arch/x86/kernel/kexec-bzimage64.c       | 2 +-
 certs/system_keyring.c                  | 3 ++-
 crypto/asymmetric_keys/pkcs7_key_type.c | 2 +-
 include/linux/verification.h            | 4 ++++
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 74628275..97d199a3 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -532,7 +532,7 @@ static int bzImage64_cleanup(void *loader_data)
 static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
 {
 	return verify_pefile_signature(kernel, kernel_len,
-				       ((struct key *)1UL),
+				       TRUST_SECONDARY_KEYRING,
 				       VERIFYING_KEXEC_PE_SIGNATURE);
 }
 #endif
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 6251d1b2..777ac7d2 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 == TRUST_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 e284d9cb..0783e555 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,
+				      TRUST_SECONDARY_KEYRING, usage,
 				      pkcs7_view_content, prep);
 }
 
diff --git a/include/linux/verification.h b/include/linux/verification.h
index a10549a6..5a7f2053 100644
--- a/include/linux/verification.h
+++ b/include/linux/verification.h
@@ -12,6 +12,10 @@
 #ifndef _LINUX_VERIFICATION_H
 #define _LINUX_VERIFICATION_H
 
+// Allow both builtin trusted keys and secondary trusted keys
+#ifndef TRUST_SECONDARY_KEYRING
+#define TRUST_SECONDARY_KEYRING ((struct key *)1UL)
+
 /*
  * The use to which an asymmetric key is being put.
  */
-- 
2.17.1