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