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