xbps/lib/verifysig.c

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/*-
* Copyright (c) 2013-2014 Juan Romero Pardines.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <libgen.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <openssl/err.h>
#include <openssl/sha.h>
#include <openssl/rsa.h>
#include <openssl/ssl.h>
#include <openssl/pem.h>
#include "xbps_api_impl.h"
static bool
rsa_verify_hash(struct xbps_repo *repo, xbps_data_t pubkey,
unsigned char *sig, unsigned int siglen,
unsigned char *sha256)
{
BIO *bio;
RSA *rsa;
int rv;
ERR_load_crypto_strings();
SSL_load_error_strings();
bio = BIO_new_mem_buf(__UNCONST(xbps_data_data_nocopy(pubkey)),
xbps_data_size(pubkey));
assert(bio);
rsa = PEM_read_bio_RSA_PUBKEY(bio, NULL, NULL, NULL);
if (rsa == NULL) {
xbps_dbg_printf(repo->xhp, "`%s' error reading public key: %s\n",
repo->uri, ERR_error_string(ERR_get_error(), NULL));
return false;
}
rv = RSA_verify(NID_sha1, sha256, SHA256_DIGEST_LENGTH, sig, siglen, rsa);
RSA_free(rsa);
BIO_free(bio);
ERR_free_strings();
return rv ? true : false;
}
bool
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xbps_verify_digest_signature(struct xbps_repo *repo, xbps_dictionary_t idxmeta,
unsigned char *sig_buf, size_t sigfilelen, unsigned char *digest)
{
xbps_dictionary_t repokeyd = NULL;
xbps_data_t pubkey;
char *hexfp = NULL;
char *rkeyfile = NULL;
bool val = false;
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if (!xbps_dictionary_count(idxmeta)) {
xbps_dbg_printf(repo->xhp, "%s: unsigned repository\n", repo->uri);
return false;
}
hexfp = xbps_pubkey2fp(repo->xhp,
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xbps_dictionary_get(idxmeta, "public-key"));
if (hexfp == NULL) {
xbps_dbg_printf(repo->xhp, "%s: incomplete signed repo, missing hexfp obj\n", repo->uri);
return false;
}
/*
* Prepare repository RSA public key to verify fname signature.
*/
rkeyfile = xbps_xasprintf("%s/keys/%s.plist", repo->xhp->metadir, hexfp);
repokeyd = xbps_plist_dictionary_from_file(repo->xhp, rkeyfile);
if (xbps_object_type(repokeyd) != XBPS_TYPE_DICTIONARY) {
xbps_dbg_printf(repo->xhp, "cannot read rkey data at %s: %s\n",
rkeyfile, strerror(errno));
goto out;
}
pubkey = xbps_dictionary_get(repokeyd, "public-key");
if (xbps_object_type(pubkey) != XBPS_TYPE_DATA)
goto out;
/*
* Verify fname RSA signature.
*/
if (rsa_verify_hash(repo, pubkey, sig_buf, sigfilelen, digest))
val = true;
out:
if (hexfp)
free(hexfp);
if (rkeyfile)
free(rkeyfile);
if (repokeyd)
xbps_object_release(repokeyd);
return val;
}
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bool
xbps_verify_signature(struct xbps_repo *repo, const char *sigfile,
unsigned char *digest)
{
unsigned char *sig_buf = NULL;
size_t sigbuflen, sigfilelen;
bool result = false;
if (xbps_mmap_file(sigfile, (void *)&sig_buf, &sigbuflen, &sigfilelen)) {
result = xbps_verify_digest_signature(repo, repo->idxmeta, sig_buf, sigfilelen, digest);
} else {
xbps_dbg_printf(repo->xhp, "can't open signature file %s: %s\n",
sigfile, strerror(errno));
}
if (sig_buf)
(void)munmap(sig_buf, sigbuflen);
return result;
}
bool
xbps_verify_file_signature(struct xbps_repo *repo, const char *fname)
{
char sig[PATH_MAX];
unsigned char *digest = NULL;
bool val = false;
if (!(digest = xbps_file_hash_raw(fname))) {
xbps_dbg_printf(repo->xhp, "can't open file %s: %s\n", fname, strerror(errno));
return false;
}
snprintf(sig, sizeof sig, "%s.sig", fname);
val = xbps_verify_signature(repo, sig, digest);
free(digest);
return val;
}