| 1 | |
| 2 | *
|
| 3 | * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
|
| 4 | * Written by David Howells ([email protected])
|
| 5 | *
|
| 6 | * This program is free software; you can redistribute it and/or
|
| 7 | * modify it under the terms of the GNU General Public Licence
|
| 8 | * as published by the Free Software Foundation; either version
|
| 9 | * 2 of the Licence, or (at your option) any later version.
|
| 10 |
|
| 11 |
|
| 12 | #include <linux/kernel.h>
|
| 13 | #include <linux/errno.h>
|
| 14 | #include <linux/string.h>
|
| 15 | #include <linux/verification.h>
|
| 16 | #include <crypto/public_key.h>
|
| 17 | #include "module-internal.h"
|
| 18 |
|
| 19 | enum pkey_id_type {
|
| 20 | PKEY_ID_PGP,
|
| 21 | PKEY_ID_X509,
|
| 22 | PKEY_ID_PKCS7,
|
| 23 | };
|
| 24 |
|
| 25 | |
| 26 | * Module signature information block.
|
| 27 | *
|
| 28 | * The constituents of the signature section are, in order:
|
| 29 | *
|
| 30 | * - Signer's name
|
| 31 | * - Key identifier
|
| 32 | * - Signature data
|
| 33 | * - Information block
|
| 34 |
|
| 35 | struct module_signature {
|
| 36 | u8 algo;
|
| 37 | u8 hash;
|
| 38 | u8 id_type;
|
| 39 | u8 signer_len;
|
| 40 | u8 key_id_len;
|
| 41 | u8 __pad[3];
|
| 42 | __be32 sig_len;
|
| 43 | };
|
| 44 |
|
| 45 | |
| 46 | * Verify the signature on a module.
|
| 47 |
|
| 48 | int mod_verify_sig(const void *mod, struct load_info *info)
|
| 49 | {
|
| 50 | struct module_signature ms;
|
| 51 | size_t sig_len, modlen = info->len;
|
| 52 |
|
| 53 | pr_devel("==>%s(,%zu)\n", __func__, modlen);
|
| 54 |
|
| 55 | if (modlen <= sizeof(ms))
|
| 56 | return -EBADMSG;
|
| 57 |
|
| 58 | memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
|
| 59 | modlen -= sizeof(ms);
|
| 60 |
|
| 61 | sig_len = be32_to_cpu(ms.sig_len);
|
| 62 | if (sig_len >= modlen)
|
| 63 | return -EBADMSG;
|
| 64 | modlen -= sig_len;
|
| 65 | info->len = modlen;
|
| 66 |
|
| 67 | if (ms.id_type != PKEY_ID_PKCS7) {
|
| 68 | pr_err("%s: Module is not signed with expected PKCS#7 message\n",
|
| 69 | info->name);
|
| 70 | return -ENOPKG;
|
| 71 | }
|
| 72 |
|
| 73 | if (ms.algo != 0 ||
|
| 74 | ms.hash != 0 ||
|
| 75 | ms.signer_len != 0 ||
|
| 76 | ms.key_id_len != 0 ||
|
| 77 | ms.__pad[0] != 0 ||
|
| 78 | ms.__pad[1] != 0 ||
|
| 79 | ms.__pad[2] != 0) {
|
| 80 | pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
|
| 81 | info->name);
|
| 82 | return -EBADMSG;
|
| 83 | }
|
| 84 |
|
| 85 | return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
|
| 86 | VERIFY_USE_SECONDARY_KEYRING,
|
| 87 | VERIFYING_MODULE_SIGNATURE,
|
| 88 | NULL, NULL);
|
| 89 | }
|