File 0006-appended-signatures-Parse-ASN1-node.patch of Package grub2
From 00e2db3ea831ab07b2bf732c200d1a64881a2a95 Mon Sep 17 00:00:00 2001
From: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Date: Mon, 25 Aug 2025 16:38:28 +0530
Subject: [PATCH 06/18] appended signatures: Parse ASN1 node
This code allows us to parse ASN1 node and allocating memory to store it.
It will work for anything where the size libtasn1 returns is right:
- Integers
- Octet strings
- DER encoding of other structures
It will _not_ work for things where libtasn1 size requires adjustment:
- Strings that require an extra NULL byte at the end
- Bit strings because libtasn1 returns the length in bits, not bytes.
If the function returns a non-NULL value, the caller must free it.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Avnish Chouhan <avnish@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/commands/appendedsig/appendedsig.h | 42 +++++++++
grub-core/commands/appendedsig/asn1util.c | 96 ++++++++++++++++++++
2 files changed, 138 insertions(+)
create mode 100644 grub-core/commands/appendedsig/appendedsig.h
create mode 100644 grub-core/commands/appendedsig/asn1util.c
diff --git a/grub-core/commands/appendedsig/appendedsig.h b/grub-core/commands/appendedsig/appendedsig.h
new file mode 100644
index 000000000..91cc040bb
--- /dev/null
+++ b/grub-core/commands/appendedsig/appendedsig.h
@@ -0,0 +1,42 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020, 2022 Free Software Foundation, Inc.
+ * Copyright (C) 2020, 2022, 2025 IBM Corporation
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/libtasn1.h>
+
+extern asn1_node grub_gnutls_gnutls_asn;
+extern asn1_node grub_gnutls_pkix_asn;
+
+/* Do libtasn1 init. */
+extern int
+asn1_init (void);
+
+/*
+ * Read a value from an ASN1 node, allocating memory to store it.
+ * It will work for anything where the size libtasn1 returns is right:
+ * - Integers
+ * - Octet strings
+ * - DER encoding of other structures
+ * It will _not_ work for things where libtasn1 size requires adjustment:
+ * - Strings that require an extra null byte at the end
+ * - Bit strings because libtasn1 returns the length in bits, not bytes.
+ *
+ * If the function returns a non-NULL value, the caller must free it.
+ */
+extern void *
+grub_asn1_allocate_and_read (asn1_node node, const char *name, const char *friendly_name, int *content_size);
diff --git a/grub-core/commands/appendedsig/asn1util.c b/grub-core/commands/appendedsig/asn1util.c
new file mode 100644
index 000000000..7e7ee264b
--- /dev/null
+++ b/grub-core/commands/appendedsig/asn1util.c
@@ -0,0 +1,96 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020, 2022 Free Software Foundation, Inc.
+ * Copyright (C) 2020, 2022, 2025 IBM Corporation
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/libtasn1.h>
+#include <grub/types.h>
+#include <grub/err.h>
+#include <grub/mm.h>
+#include <grub/crypto.h>
+#include <grub/misc.h>
+#include <grub/gcrypt/gcrypt.h>
+
+#include "appendedsig.h"
+
+asn1_node grub_gnutls_gnutls_asn = NULL;
+asn1_node grub_gnutls_pkix_asn = NULL;
+
+extern const asn1_static_node grub_gnutls_asn1_tab[];
+extern const asn1_static_node grub_pkix_asn1_tab[];
+
+/*
+ * Read a value from an ASN1 node, allocating memory to store it.
+ * It will work for anything where the size libtasn1 returns is right:
+ * - Integers
+ * - Octet strings
+ * - DER encoding of other structures
+ * It will _not_ work for things where libtasn1 size requires adjustment:
+ * - Strings that require an extra NULL byte at the end
+ * - Bit strings because libtasn1 returns the length in bits, not bytes.
+ * If the function returns a non-NULL value, the caller must free it.
+ */
+void *
+grub_asn1_allocate_and_read (asn1_node node, const char *name, const char *friendly_name, int *content_size)
+{
+ int result;
+ grub_uint8_t *tmpstr = NULL;
+ int tmpstr_size = 0;
+
+ result = asn1_read_value (node, name, NULL, &tmpstr_size);
+ if (result != ASN1_MEM_ERROR)
+ {
+ grub_error (GRUB_ERR_BAD_FILE_TYPE, "reading size of %s did not return expected status: %s",
+ friendly_name, asn1_strerror (result)) ;
+ return NULL;
+ }
+
+ tmpstr = grub_malloc (tmpstr_size);
+ if (tmpstr == NULL)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, "could not allocate memory to store %s",
+ friendly_name) ;
+ return NULL;
+ }
+
+ result = asn1_read_value (node, name, tmpstr, &tmpstr_size);
+ if (result != ASN1_SUCCESS)
+ {
+ grub_free (tmpstr);
+ grub_error (GRUB_ERR_BAD_FILE_TYPE, "error reading %s: %s", friendly_name,
+ asn1_strerror (result)) ;
+ return NULL;
+ }
+
+ *content_size = tmpstr_size;
+
+ return tmpstr;
+}
+
+int
+asn1_init (void)
+{
+ int res;
+
+ res = asn1_array2tree (grub_gnutls_asn1_tab, &grub_gnutls_gnutls_asn, NULL);
+ if (res != ASN1_SUCCESS)
+ return res;
+
+ res = asn1_array2tree (grub_pkix_asn1_tab, &grub_gnutls_pkix_asn, NULL);
+
+ return res;
+}
--
2.43.0
