| 1 | // SPDX-License-Identifier: GPL-2.0+ |
|---|---|
| 2 | /* |
| 3 | * Module signature checker |
| 4 | * |
| 5 | * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. |
| 6 | * Written by David Howells (dhowells@redhat.com) |
| 7 | */ |
| 8 | |
| 9 | #include <linux/errno.h> |
| 10 | #include <linux/printk.h> |
| 11 | #include <linux/module_signature.h> |
| 12 | #include <asm/byteorder.h> |
| 13 | |
| 14 | /** |
| 15 | * mod_check_sig - check that the given signature is sane |
| 16 | * |
| 17 | * @ms: Signature to check. |
| 18 | * @file_len: Size of the file to which @ms is appended. |
| 19 | * @name: What is being checked. Used for error messages. |
| 20 | */ |
| 21 | int mod_check_sig(const struct module_signature *ms, size_t file_len, |
| 22 | const char *name) |
| 23 | { |
| 24 | if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms)) |
| 25 | return -EBADMSG; |
| 26 | |
| 27 | if (ms->id_type != PKEY_ID_PKCS7) { |
| 28 | pr_err("%s: not signed with expected PKCS#7 message\n", |
| 29 | name); |
| 30 | return -ENOPKG; |
| 31 | } |
| 32 | |
| 33 | if (ms->algo != 0 || |
| 34 | ms->hash != 0 || |
| 35 | ms->signer_len != 0 || |
| 36 | ms->key_id_len != 0 || |
| 37 | ms->__pad[0] != 0 || |
| 38 | ms->__pad[1] != 0 || |
| 39 | ms->__pad[2] != 0) { |
| 40 | pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n", |
| 41 | name); |
| 42 | return -EBADMSG; |
| 43 | } |
| 44 | |
| 45 | return 0; |
| 46 | } |
| 47 |