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![Randy Dunlap](/assets/img/avatar_default.png)
Fix the warning: kernel/module_signing.c:195:2: warning: format '%lu' expects type 'long unsigned int', but argument 3 has type 'size_t' by using the proper 'z' modifier for printing a size_t. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
249 lines
5.9 KiB
C
249 lines
5.9 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 <linux/err.h>
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#include <crypto/public_key.h>
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#include <crypto/hash.h>
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#include <keys/asymmetric-type.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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enum pkey_algo algo : 8; /* Public-key crypto algorithm */
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enum pkey_hash_algo hash : 8; /* Digest algorithm */
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enum pkey_id_type id_type : 8; /* Key identifier type */
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u8 signer_len; /* Length of signer's name */
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u8 key_id_len; /* Length of key identifier */
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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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* Digest the module contents.
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*/
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static struct public_key_signature *mod_make_digest(enum pkey_hash_algo hash,
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const void *mod,
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unsigned long modlen)
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{
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struct public_key_signature *pks;
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struct crypto_shash *tfm;
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struct shash_desc *desc;
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size_t digest_size, desc_size;
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int ret;
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pr_devel("==>%s()\n", __func__);
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/* Allocate the hashing algorithm we're going to need and find out how
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* big the hash operational data will be.
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*/
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tfm = crypto_alloc_shash(pkey_hash_algo[hash], 0, 0);
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if (IS_ERR(tfm))
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return (PTR_ERR(tfm) == -ENOENT) ? ERR_PTR(-ENOPKG) : ERR_CAST(tfm);
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desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
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digest_size = crypto_shash_digestsize(tfm);
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/* We allocate the hash operational data storage on the end of our
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* context data and the digest output buffer on the end of that.
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*/
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ret = -ENOMEM;
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pks = kzalloc(digest_size + sizeof(*pks) + desc_size, GFP_KERNEL);
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if (!pks)
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goto error_no_pks;
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pks->pkey_hash_algo = hash;
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pks->digest = (u8 *)pks + sizeof(*pks) + desc_size;
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pks->digest_size = digest_size;
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desc = (void *)pks + sizeof(*pks);
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desc->tfm = tfm;
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desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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ret = crypto_shash_init(desc);
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if (ret < 0)
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goto error;
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ret = crypto_shash_finup(desc, mod, modlen, pks->digest);
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if (ret < 0)
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goto error;
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crypto_free_shash(tfm);
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pr_devel("<==%s() = ok\n", __func__);
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return pks;
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error:
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kfree(pks);
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error_no_pks:
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crypto_free_shash(tfm);
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pr_devel("<==%s() = %d\n", __func__, ret);
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return ERR_PTR(ret);
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}
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/*
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* Extract an MPI array from the signature data. This represents the actual
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* signature. Each raw MPI is prefaced by a BE 2-byte value indicating the
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* size of the MPI in bytes.
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*
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* RSA signatures only have one MPI, so currently we only read one.
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*/
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static int mod_extract_mpi_array(struct public_key_signature *pks,
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const void *data, size_t len)
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{
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size_t nbytes;
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MPI mpi;
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if (len < 3)
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return -EBADMSG;
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nbytes = ((const u8 *)data)[0] << 8 | ((const u8 *)data)[1];
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data += 2;
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len -= 2;
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if (len != nbytes)
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return -EBADMSG;
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mpi = mpi_read_raw_data(data, nbytes);
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if (!mpi)
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return -ENOMEM;
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pks->mpi[0] = mpi;
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pks->nr_mpi = 1;
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return 0;
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}
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/*
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* Request an asymmetric key.
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*/
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static struct key *request_asymmetric_key(const char *signer, size_t signer_len,
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const u8 *key_id, size_t key_id_len)
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{
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key_ref_t key;
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size_t i;
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char *id, *q;
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pr_devel("==>%s(,%zu,,%zu)\n", __func__, signer_len, key_id_len);
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/* Construct an identifier. */
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id = kmalloc(signer_len + 2 + key_id_len * 2 + 1, GFP_KERNEL);
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if (!id)
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return ERR_PTR(-ENOKEY);
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memcpy(id, signer, signer_len);
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q = id + signer_len;
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*q++ = ':';
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*q++ = ' ';
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for (i = 0; i < key_id_len; i++) {
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*q++ = hex_asc[*key_id >> 4];
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*q++ = hex_asc[*key_id++ & 0x0f];
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}
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*q = 0;
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pr_debug("Look up: \"%s\"\n", id);
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key = keyring_search(make_key_ref(modsign_keyring, 1),
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&key_type_asymmetric, id);
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if (IS_ERR(key))
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pr_warn("Request for unknown module key '%s' err %ld\n",
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id, PTR_ERR(key));
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kfree(id);
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if (IS_ERR(key)) {
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switch (PTR_ERR(key)) {
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/* Hide some search errors */
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case -EACCES:
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case -ENOTDIR:
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case -EAGAIN:
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return ERR_PTR(-ENOKEY);
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default:
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return ERR_CAST(key);
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}
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}
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pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key_ref_to_ptr(key)));
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return key_ref_to_ptr(key);
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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 public_key_signature *pks;
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struct module_signature ms;
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struct key *key;
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const void *sig;
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size_t modlen = *_modlen, sig_len;
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int ret;
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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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if ((size_t)ms.signer_len + ms.key_id_len >= modlen)
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return -EBADMSG;
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modlen -= (size_t)ms.signer_len + ms.key_id_len;
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*_modlen = modlen;
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sig = mod + modlen;
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/* For the moment, only support RSA and X.509 identifiers */
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if (ms.algo != PKEY_ALGO_RSA ||
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ms.id_type != PKEY_ID_X509)
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return -ENOPKG;
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if (ms.hash >= PKEY_HASH__LAST ||
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!pkey_hash_algo[ms.hash])
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return -ENOPKG;
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key = request_asymmetric_key(sig, ms.signer_len,
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sig + ms.signer_len, ms.key_id_len);
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if (IS_ERR(key))
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return PTR_ERR(key);
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pks = mod_make_digest(ms.hash, mod, modlen);
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if (IS_ERR(pks)) {
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ret = PTR_ERR(pks);
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goto error_put_key;
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}
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ret = mod_extract_mpi_array(pks, sig + ms.signer_len + ms.key_id_len,
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sig_len);
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if (ret < 0)
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goto error_free_pks;
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ret = verify_signature(key, pks);
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pr_devel("verify_signature() = %d\n", ret);
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error_free_pks:
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mpi_free(pks->rsa.s);
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kfree(pks);
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error_put_key:
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key_put(key);
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pr_devel("<==%s() = %d\n", __func__, ret);
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return ret;
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}
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