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From 3ce5852ec6add45a28fe1706e9163351940e905c Mon Sep 17 00:00:00 2001
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From: Peter Jones <pjones@redhat.com>
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Date: Mon, 2 Oct 2017 18:25:29 -0400
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Subject: [PATCH 1/3] Make get_cert_list() not complain about cert lists that
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 aren't present.
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Signed-off-by: Peter Jones <pjones@redhat.com>
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---
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 security/integrity/platform_certs/load_uefi.c | 37 ++++++++++++++++++++++---------------
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 1 file changed, 22 insertions(+), 15 deletions(-)
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diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
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index 81b19c52832b..e188f3ecbce3 100644
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--- a/security/integrity/platform_certs/load_uefi.c
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+++ b/security/integrity/platform_certs/load_uefi.c
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@@ -38,8 +38,8 @@ static __init bool uefi_check_ignore_db(void)
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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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-				  unsigned long *size)
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+static __init int get_cert_list(efi_char16_t *name, efi_guid_t *guid,
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+				  unsigned long *size , void **cert_list)
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 {
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 	efi_status_t status;
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 	unsigned long lsize = 4;
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@@ -47,24 +47,31 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
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 	void *db;
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 	status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
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+	if (status == EFI_NOT_FOUND) {
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+		*size = 0;
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+		*cert_list = NULL;
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+		return 0;
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+	}
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+
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 	if (status != EFI_BUFFER_TOO_SMALL) {
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 		pr_err("Couldn't get size: 0x%lx\n", status);
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-		return NULL;
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+		return efi_status_to_err(status);
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 	}
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 	db = kmalloc(lsize, GFP_KERNEL);
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 	if (!db)
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-		return NULL;
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+		return -ENOMEM;
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 	status = efi.get_variable(name, guid, NULL, &lsize, db);
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 	if (status != EFI_SUCCESS) {
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 		kfree(db);
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 		pr_err("Error reading db var: 0x%lx\n", status);
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-		return NULL;
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+		return efi_status_to_err(status);
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 	}
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 	*size = lsize;
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-	return db;
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+	*cert_list = db;
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+	return 0;
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 }
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 /*
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@@ -153,10 +160,10 @@ static int __init load_uefi_certs(void)
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 	 * an error if we can't get them.
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 	 */
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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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+		rc = get_cert_list(L"db", &secure_var, &dbsize, &db);
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+		if (rc < 0) {
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 			pr_err("MODSIGN: Couldn't get UEFI db list\n");
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-		} else {
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+		} else if (dbsize != 0) {
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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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@@ -166,10 +173,10 @@ static int __init load_uefi_certs(void)
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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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-	if (!mok) {
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+	rc = get_cert_list(L"MokListRT", &mok_var, &moksize, &mok);
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+	if (rc < 0) {
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 		pr_info("Couldn't get UEFI MokListRT\n");
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-	} else {
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+	} else if (moksize != 0) {
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 		rc = parse_efi_signature_list("UEFI:MokListRT",
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 					      mok, moksize, get_handler_for_db);
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 		if (rc)
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@@ -177,10 +184,10 @@ static int __init load_uefi_certs(void)
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 		kfree(mok);
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 	}
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-	dbx = get_cert_list(L"dbx", &secure_var, &dbxsize);
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-	if (!dbx) {
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+	rc = get_cert_list(L"dbx", &secure_var, &dbxsize, &dbx);
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+	if (rc < 0) {
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 		pr_info("Couldn't get UEFI dbx list\n");
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-	} else {
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+	} else if (dbxsize != 0) {
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 		rc = parse_efi_signature_list("UEFI:dbx",
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 					      dbx, dbxsize,
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 					      get_handler_for_dbx);