89 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From 9f1958a0cc911e1f79b2733ee5029dbd819ff328 Mon Sep 17 00:00:00 2001
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| From: Josh Boyer <jwboyer@fedoraproject.org>
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| Date: Fri, 5 May 2017 08:21:59 +0100
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| Subject: [PATCH 4/4] MODSIGN: Allow the "db" UEFI variable to be suppressed
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| 
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| If a user tells shim to not use the certs/hashes in the UEFI db variable
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| for verification purposes, shim will set a UEFI variable called
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| MokIgnoreDB.  Have the uefi import code look for this and ignore the db
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| variable if it is found.
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| 
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| Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
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| Signed-off-by: David Howells <dhowells@redhat.com>
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| ---
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|  certs/load_uefi.c | 44 ++++++++++++++++++++++++++++++++++----------
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|  1 file changed, 34 insertions(+), 10 deletions(-)
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| 
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| diff --git a/certs/load_uefi.c b/certs/load_uefi.c
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| index b44e464..3d88459 100644
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| --- a/certs/load_uefi.c
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| +++ b/certs/load_uefi.c
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| @@ -13,6 +13,26 @@ static __initdata efi_guid_t efi_cert_x509_sha256_guid = EFI_CERT_X509_SHA256_GU
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|  static __initdata efi_guid_t efi_cert_sha256_guid = EFI_CERT_SHA256_GUID;
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| 
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|  /*
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| + * Look to see if a UEFI variable called MokIgnoreDB exists and return true if
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| + * it does.
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| + *
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| + * This UEFI variable is set by the shim if a user tells the shim to not use
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| + * the certs/hashes in the UEFI db variable for verification purposes.  If it
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| + * is set, we should ignore the db variable also and the true return indicates
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| + * this.
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| + */
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| +static __init bool uefi_check_ignore_db(void)
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| +{
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| +	efi_status_t status;
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| +	unsigned int db = 0;
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| +	unsigned long size = sizeof(db);
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| +	efi_guid_t guid = EFI_SHIM_LOCK_GUID;
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| +
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| +	status = efi.get_variable(L"MokIgnoreDB", &guid, NULL, &size, &db);
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| +	return status == EFI_SUCCESS;
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| +}
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| +
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| +/*
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|   * Get a certificate list blob from the named EFI variable.
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|   */
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|  static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
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| @@ -113,7 +133,9 @@ static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_ty
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|  }
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| 
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|  /*
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| - * Load the certs contained in the UEFI databases
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| + * Load the certs contained in the UEFI databases into the secondary trusted
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| + * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
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| + * keyring.
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|   */
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|  static int __init load_uefi_certs(void)
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|  {
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| @@ -129,15 +151,17 @@ static int __init load_uefi_certs(void)
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|  	/* Get db, MokListRT, and dbx.  They might not exist, so it isn't
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|  	 * an error if we can't get them.
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|  	 */
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| -	db = get_cert_list(L"db", &secure_var, &dbsize);
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| -	if (!db) {
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| -		pr_err("MODSIGN: Couldn't get UEFI db list\n");
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| -	} else {
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| -		rc = parse_efi_signature_list("UEFI:db",
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| -					      db, dbsize, get_handler_for_db);
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| -		if (rc)
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| -			pr_err("Couldn't parse db signatures: %d\n", rc);
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| -		kfree(db);
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| +	if (!uefi_check_ignore_db()) {
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| +		db = get_cert_list(L"db", &secure_var, &dbsize);
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| +		if (!db) {
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| +			pr_err("MODSIGN: Couldn't get UEFI db list\n");
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| +		} else {
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| +			rc = parse_efi_signature_list("UEFI:db",
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| +						      db, dbsize, get_handler_for_db);
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| +			if (rc)
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| +				pr_err("Couldn't parse db signatures: %d\n", rc);
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| +			kfree(db);
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| +		}
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|  	}
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| 
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|  	mok = get_cert_list(L"MokListRT", &mok_var, &moksize);
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| -- 
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| 2.9.3
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| 
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