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security/integrity: fix pointer to ESL data and its size on pseries

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On PowerVM guest, variable data is prefixed with 8 bytes of timestamp.
Extract ESL by stripping off the timestamp before passing to ESL parser.

Fixes: 4b3e71e9a3 ("integrity/powerpc: Support loading keys from PLPKS")
Cc: stable@vger.kenrnel.org # v6.3
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230608120444.382527-1-nayna@linux.ibm.com
This commit is contained in:
Nayna Jain 2023-06-08 08:04:44 -04:00 committed by Michael Ellerman
parent c8eebc4a99
commit e66effaf61
1 changed files with 26 additions and 14 deletions
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40
security/integrity/platform_certs/load_powerpc.c
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@ -15,6 +15,9 @@
#include "keyring_handler.h"
#include "../integrity.h"
#define extract_esl(db, data, size, offset) \
do { db = data + offset; size = size - offset; } while (0)
/*
* Get a certificate list blob from the named secure variable.
*
@ -55,8 +58,9 @@ static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
*/
static int __init load_powerpc_certs(void)
{
void *db = NULL, *dbx = NULL;
u64 dbsize = 0, dbxsize = 0;
void *db = NULL, *dbx = NULL, *data = NULL;
u64 dsize = 0;
u64 offset = 0;
int rc = 0;
ssize_t len;
char buf[32];
@ -74,38 +78,46 @@ static int __init load_powerpc_certs(void)
return -ENODEV;
}
if (strcmp("ibm,plpks-sb-v1", buf) == 0)
/* PLPKS authenticated variables ESL data is prefixed with 8 bytes of timestamp */
offset = 8;
/*
* Get db, and dbx. They might not exist, so it isn't an error if we
* can't get them.
*/
db = get_cert_list("db", 3, &dbsize);
if (!db) {
data = get_cert_list("db", 3, &dsize);
if (!data) {
pr_info("Couldn't get db list from firmware\n");
} else if (IS_ERR(db)) {
rc = PTR_ERR(db);
} else if (IS_ERR(data)) {
rc = PTR_ERR(data);
pr_err("Error reading db from firmware: %d\n", rc);
return rc;
} else {
rc = parse_efi_signature_list("powerpc:db", db, dbsize,
extract_esl(db, data, dsize, offset);
rc = parse_efi_signature_list("powerpc:db", db, dsize,
get_handler_for_db);
if (rc)
pr_err("Couldn't parse db signatures: %d\n", rc);
kfree(db);
kfree(data);
}
dbx = get_cert_list("dbx", 4, &dbxsize);
if (!dbx) {
data = get_cert_list("dbx", 4, &dsize);
if (!data) {
pr_info("Couldn't get dbx list from firmware\n");
} else if (IS_ERR(dbx)) {
rc = PTR_ERR(dbx);
} else if (IS_ERR(data)) {
rc = PTR_ERR(data);
pr_err("Error reading dbx from firmware: %d\n", rc);
return rc;
} else {
rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
extract_esl(dbx, data, dsize, offset);
rc = parse_efi_signature_list("powerpc:dbx", dbx, dsize,
get_handler_for_dbx);
if (rc)
pr_err("Couldn't parse dbx signatures: %d\n", rc);
kfree(dbx);
kfree(data);
}
return rc;