[PATCH v6 25/26] integrity/powerpc: Improve error handling & reporting when loading certs

Andrew Donnellan
2023-02-10T08:06:28Z

From: Russell Currey <ruscur@russell.cc>

A few improvements to load_powerpc.c:

- include integrity.h for the pr_fmt()
- move all error reporting out of get_cert_list()
- use ERR_PTR() to better preserve error detail
- don't use pr_err() for missing keys

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>

---

v3: New patch
---
.../integrity/platform_certs/load_powerpc.c | 26 ++++++++++++++-----
1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c
index 1e4f80a4e71c..dee51606d5f4 100644
--- a/security/integrity/platform_certs/load_powerpc.c
+++ b/security/integrity/platform_certs/load_powerpc.c
@@ -14,9 +14,15 @@
#include <asm/secure_boot.h>
#include <asm/secvar.h>
#include "keyring_handler.h"
+#include "../integrity.h"

/*
* Get a certificate list blob from the named secure variable.
+ *
+ * Returns:
+ * - a pointer to a kmalloc'd buffer containing the cert list on success
+ * - NULL if the key does not exist
+ * - an ERR_PTR on error
*/
static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
{
@@ -25,19 +31,19 @@ static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)

rc = secvar_ops->get(key, keylen, NULL, size);
if (rc) {
- pr_err("Couldn't get size: %d\n", rc);
- return NULL;
+ if (rc == -ENOENT)
+ return NULL;
+ return ERR_PTR(rc);
}

db = kmalloc(*size, GFP_KERNEL);
if (!db)
- return NULL;
+ return ERR_PTR(-ENOMEM);

rc = secvar_ops->get(key, keylen, db, size);
if (rc) {
kfree(db);
- pr_err("Error reading %s var: %d\n", key, rc);
- return NULL;
+ return ERR_PTR(rc);
}

return db;
@@ -69,7 +75,11 @@ static int __init load_powerpc_certs(void)
*/
db = get_cert_list("db", 3, &dbsize);
if (!db) {
- pr_err("Couldn't get db list from firmware\n");
+ pr_info("Couldn't get db list from firmware\n");
+ } else if (IS_ERR(db)) {
+ rc = PTR_ERR(db);
+ pr_err("Error reading db from firmware: %d\n", rc);
+ return rc;
} else {
rc = parse_efi_signature_list("powerpc:db", db, dbsize,
get_handler_for_db);
@@ -81,6 +91,10 @@ static int __init load_powerpc_certs(void)
dbx = get_cert_list("dbx", 4, &dbxsize);
if (!dbx) {
pr_info("Couldn't get dbx list from firmware\n");
+ } else if (IS_ERR(dbx)) {
+ rc = PTR_ERR(dbx);
+ pr_err("Error reading dbx from firmware: %d\n", rc);
+ return rc;
} else {
rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
get_handler_for_dbx);
--
2.39.1