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f87dc57a71
From Jan Engelhardt: Program received signal SIGBUS, Bus error. [Switching to process 11100] 0x00035278 in kmod_module_signature_info (file=0x4eeb8, sig_info=0xffffc254) at libkmod/libkmod-signature.c:124 124 sig_len = be32toh(modsig->sig_len); (gdb) p modsig $1 = (const struct module_signature *) 0xf7dfe143 modsig->sig_len can be unaligned if modsig is unaligned, so the padding in the struct has no effect since we are mapping it to the mem buffer.
142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
/*
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* libkmod - module signature display
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*
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* Copyright (C) 2013 Michal Marek, SUSE
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <endian.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include "libkmod-internal.h"
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/* These types and tables were copied from the 3.7 kernel sources.
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* As this is just description of the signature format, it should not be
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* considered derived work (so libkmod can use the LGPL license).
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*/
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enum pkey_algo {
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PKEY_ALGO_DSA,
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PKEY_ALGO_RSA,
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PKEY_ALGO__LAST
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};
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static const char *const pkey_algo[PKEY_ALGO__LAST] = {
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[PKEY_ALGO_DSA] = "DSA",
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[PKEY_ALGO_RSA] = "RSA",
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};
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enum pkey_hash_algo {
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PKEY_HASH_MD4,
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PKEY_HASH_MD5,
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PKEY_HASH_SHA1,
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PKEY_HASH_RIPE_MD_160,
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PKEY_HASH_SHA256,
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PKEY_HASH_SHA384,
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PKEY_HASH_SHA512,
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PKEY_HASH_SHA224,
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PKEY_HASH__LAST
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};
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const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
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[PKEY_HASH_MD4] = "md4",
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[PKEY_HASH_MD5] = "md5",
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[PKEY_HASH_SHA1] = "sha1",
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[PKEY_HASH_RIPE_MD_160] = "rmd160",
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[PKEY_HASH_SHA256] = "sha256",
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[PKEY_HASH_SHA384] = "sha384",
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[PKEY_HASH_SHA512] = "sha512",
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[PKEY_HASH_SHA224] = "sha224",
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};
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enum pkey_id_type {
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PKEY_ID_PGP, /* OpenPGP generated key ID */
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PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */
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PKEY_ID_TYPE__LAST
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};
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const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
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[PKEY_ID_PGP] = "PGP",
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[PKEY_ID_X509] = "X509",
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};
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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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uint8_t algo; /* Public-key crypto algorithm [enum pkey_algo] */
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uint8_t hash; /* Digest algorithm [enum pkey_hash_algo] */
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uint8_t id_type; /* Key identifier type [enum pkey_id_type] */
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uint8_t signer_len; /* Length of signer's name */
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uint8_t key_id_len; /* Length of key identifier */
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uint8_t __pad[3];
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uint32_t sig_len; /* Length of signature data (big endian) */
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};
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#define SIG_MAGIC "~Module signature appended~\n"
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bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signature_info *sig_info)
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{
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const char *mem;
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off_t size;
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const struct module_signature *modsig;
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size_t sig_len;
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size = kmod_file_get_size(file);
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mem = kmod_file_get_contents(file);
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if (size < (off_t)strlen(SIG_MAGIC))
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return false;
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size -= strlen(SIG_MAGIC);
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if (memcmp(SIG_MAGIC, mem + size, strlen(SIG_MAGIC)) != 0)
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return false;
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if (size < (off_t)sizeof(struct module_signature))
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return false;
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size -= sizeof(struct module_signature);
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modsig = (struct module_signature *)(mem + size);
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if (modsig->algo >= PKEY_ALGO__LAST ||
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modsig->hash >= PKEY_HASH__LAST ||
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modsig->id_type >= PKEY_ID_TYPE__LAST)
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return false;
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sig_len = be32toh(get_unaligned(&modsig->sig_len));
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if (size < (off_t)(modsig->signer_len + modsig->key_id_len + sig_len))
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return false;
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size -= modsig->key_id_len + sig_len;
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sig_info->key_id = mem + size;
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sig_info->key_id_len = modsig->key_id_len;
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size -= modsig->signer_len;
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sig_info->signer = mem + size;
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sig_info->signer_len = modsig->signer_len;
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sig_info->algo = pkey_algo[modsig->algo];
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sig_info->hash_algo = pkey_hash_algo[modsig->hash];
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sig_info->id_type = pkey_id_type[modsig->id_type];
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return true;
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}
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