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091f6e26eb
Extract the function that drives the PKCS#7 signature verification given a data blob and a PKCS#7 blob out from the module signing code and lump it with the system keyring code as it's generic. This makes it independent of module config options and opens it to use by the firmware loader. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ming Lei <ming.lei@canonical.com> Cc: Seth Forshee <seth.forshee@canonical.com> Cc: Kyle McMartin <kyle@kernel.org>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/* Module signature checker
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*
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <keys/system_keyring.h>
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#include <crypto/public_key.h>
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#include "module-internal.h"
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/*
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* Module signature information block.
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*
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* The constituents of the signature section are, in order:
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*
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* - Signer's name
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* - Key identifier
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* - Signature data
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* - Information block
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*/
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struct module_signature {
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u8 algo; /* Public-key crypto algorithm [0] */
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u8 hash; /* Digest algorithm [0] */
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u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */
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u8 signer_len; /* Length of signer's name [0] */
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u8 key_id_len; /* Length of key identifier [0] */
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u8 __pad[3];
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__be32 sig_len; /* Length of signature data */
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};
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/*
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* Verify the signature on a module.
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*/
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int mod_verify_sig(const void *mod, unsigned long *_modlen)
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{
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struct module_signature ms;
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size_t modlen = *_modlen, sig_len;
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pr_devel("==>%s(,%zu)\n", __func__, modlen);
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if (modlen <= sizeof(ms))
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return -EBADMSG;
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memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
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modlen -= sizeof(ms);
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sig_len = be32_to_cpu(ms.sig_len);
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if (sig_len >= modlen)
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return -EBADMSG;
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modlen -= sig_len;
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*_modlen = modlen;
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if (ms.id_type != PKEY_ID_PKCS7) {
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pr_err("Module is not signed with expected PKCS#7 message\n");
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return -ENOPKG;
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}
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if (ms.algo != 0 ||
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ms.hash != 0 ||
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ms.signer_len != 0 ||
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ms.key_id_len != 0 ||
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ms.__pad[0] != 0 ||
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ms.__pad[1] != 0 ||
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ms.__pad[2] != 0) {
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pr_err("PKCS#7 signature info has unexpected non-zero params\n");
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return -EBADMSG;
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}
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return system_verify_data(mod, modlen, mod + modlen, sig_len);
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}
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