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rpmsignverity.c
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rpmsignverity.c
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/**
* Copyright (C) 2020 Facebook
*
* Author: Jes Sorensen <[email protected]>
*/
#include "system.h"
#include <inttypes.h>
#include <rpm/rpmlib.h> /* RPMSIGTAG & related */
#include <rpm/rpmlog.h> /* rpmlog */
#include <rpm/rpmfi.h>
#include <rpm/rpmcrypto.h> /* rpmDigestLength */
#include <rpm/header.h> /* HEADERGET_MINMEM */
#include <rpm/rpmtypes.h> /* rpmRC */
#include <rpm/rpmbase64.h>
#include "header_internal.h"
#include <libfsverity.h>
#include "rpmio_internal.h"
#include "rpmvs.h"
#include "rpmsignverity.h"
#define MAX_SIGNATURE_LENGTH 1024
static int rpmVerityRead(void *opaque, void *buf, size_t size)
{
int retval;
rpmfi fi = (rpmfi)opaque;
retval = rpmfiArchiveRead(fi, buf, size);
if (retval > 0)
retval = 0;
return retval;
}
static char *rpmVeritySignFile(rpmfi fi, size_t *sig_size, char *key,
char *keypass, char *cert, uint16_t algo)
{
struct libfsverity_merkle_tree_params params;
struct libfsverity_signature_params sig_params;
struct libfsverity_digest *digest = NULL;
rpm_loff_t file_size;
char *digest_hex, *digest_base64, *sig_base64 = NULL, *sig_hex = NULL;
uint8_t *sig = NULL;
int status;
if (S_ISLNK(rpmfiFMode(fi)))
file_size = 0;
else
file_size = rpmfiFSize(fi);
memset(¶ms, 0, sizeof(struct libfsverity_merkle_tree_params));
params.version = 1;
params.hash_algorithm = algo;
params.block_size = RPM_FSVERITY_BLKSZ;
params.salt_size = 0 /* salt_size */;
params.salt = NULL /* salt */;
params.file_size = file_size;
status = libfsverity_compute_digest(fi, rpmVerityRead, ¶ms, &digest);
if (status) {
rpmlog(RPMLOG_DEBUG, _("failed to compute digest\n"));
goto out;
}
digest_hex = rpmhex(digest->digest, digest->digest_size);
digest_base64 = rpmBase64Encode(digest->digest, digest->digest_size, -1);
rpmlog(RPMLOG_DEBUG, _("file(size %" PRIu64 "): %s: digest(%i): %s, idx %i\n"),
file_size, rpmfiFN(fi), digest->digest_size, digest_hex,
rpmfiFX(fi));
rpmlog(RPMLOG_DEBUG, _("file(size %" PRIu64 "): %s: digest sz (%u): base64 sz (%zu), %s, idx %i\n"),
file_size, rpmfiFN(fi), digest->digest_size, strlen(digest_base64),
digest_base64, rpmfiFX(fi));
free(digest_hex);
memset(&sig_params, 0, sizeof(struct libfsverity_signature_params));
sig_params.keyfile = key;
sig_params.certfile = cert;
if (libfsverity_sign_digest(digest, &sig_params, &sig, sig_size)) {
rpmlog(RPMLOG_DEBUG, _("failed to sign digest\n"));
goto out;
}
sig_hex = rpmhex(sig, *sig_size);
sig_base64 = rpmBase64Encode(sig, *sig_size, -1);
rpmlog(RPMLOG_DEBUG, _("%s: sig_size(%zu), base64_size(%zu), idx %i: signature:\n%s\n"),
rpmfiFN(fi), *sig_size, strlen(sig_base64), rpmfiFX(fi), sig_hex);
out:
free(sig_hex);
free(digest);
free(sig);
return sig_base64;
}
rpmRC rpmSignVerity(FD_t fd, Header sigh, Header h, char *key,
char *keypass, char *cert, uint16_t algo)
{
rpmRC rc;
FD_t gzdi;
rpmfiles files = NULL;
rpmfi fi = NULL;
rpmfi hfi = rpmfiNew(NULL, h, RPMTAG_BASENAMES, RPMFI_FLAGS_QUERY);
rpmts ts = rpmtsCreate();
struct rpmtd_s td;
off_t offset = Ftell(fd);
const char *compr;
char *rpmio_flags = NULL;
char *sig_hex;
char **signatures = NULL;
size_t sig_size;
int nr_files, idx;
uint32_t algo32;
Fseek(fd, 0, SEEK_SET);
rpmtsSetVSFlags(ts, RPMVSF_MASK_NODIGESTS | RPMVSF_MASK_NOSIGNATURES |
RPMVSF_NOHDRCHK);
rc = rpmReadPackageFile(ts, fd, "fsverity", &h);
if (rc != RPMRC_OK) {
rpmlog(RPMLOG_DEBUG, _("%s: rpmReadPackageFile returned %i\n"),
__func__, rc);
goto out;
}
rpmlog(RPMLOG_DEBUG, _("key: %s\n"), key);
rpmlog(RPMLOG_DEBUG, _("cert: %s\n"), cert);
compr = headerGetString(h, RPMTAG_PAYLOADCOMPRESSOR);
rpmio_flags = rstrscat(NULL, "r.", compr ? compr : "gzip", NULL);
gzdi = Fdopen(fdDup(Fileno(fd)), rpmio_flags);
free(rpmio_flags);
if (!gzdi)
rpmlog(RPMLOG_DEBUG, _("Fdopen() failed\n"));
files = rpmfilesNew(NULL, h, RPMTAG_BASENAMES, RPMFI_FLAGS_QUERY);
fi = rpmfiNewArchiveReader(gzdi, files,
RPMFI_ITER_READ_ARCHIVE_OMIT_HARDLINKS);
/*
* Should this be sigh from the cloned fd or the sigh we received?
*/
headerDel(sigh, RPMSIGTAG_VERITYSIGNATURES);
headerDel(sigh, RPMSIGTAG_VERITYSIGNATUREALGO);
/*
* The payload doesn't include special files, like ghost files, and
* we cannot rely on the file order in the payload to match that of
* the header. Instead we allocate an array of pointers and populate
* it as we go along. Then walk the header fi and account for the
* special files. Last we walk the array and populate the header.
*/
nr_files = rpmfiFC(hfi);
signatures = (char **)xcalloc(nr_files, sizeof(char *));
if (!algo)
algo = FS_VERITY_HASH_ALG_SHA256;
rpmlog(RPMLOG_DEBUG, _("file count - header: %i, payload %i\n"),
nr_files, rpmfiFC(fi));
while (rpmfiNext(fi) >= 0) {
idx = rpmfiFX(fi);
signatures[idx] = rpmVeritySignFile(fi, &sig_size, key, keypass, cert,
algo);
}
while (rpmfiNext(hfi) >= 0) {
idx = rpmfiFX(hfi);
if (signatures[idx])
continue;
signatures[idx] = rpmVeritySignFile(hfi, &sig_size, key, keypass, cert,
algo);
}
rpmtdReset(&td);
td.tag = RPMSIGTAG_VERITYSIGNATURES;
td.type = RPM_STRING_ARRAY_TYPE;
td.count = 1;
for (idx = 0; idx < nr_files; idx++) {
sig_hex = signatures[idx];
td.data = &sig_hex;
if (!headerPut(sigh, &td, HEADERPUT_APPEND)) {
rpmlog(RPMLOG_ERR, _("headerPutString failed\n"));
rc = RPMRC_FAIL;
goto out;
}
rpmlog(RPMLOG_DEBUG, _("signature: %s\n"), signatures[idx]);
rpmlog(RPMLOG_DEBUG, _("digest signed, len: %zu\n"), sig_size);
free(signatures[idx]);
signatures[idx] = NULL;
}
if (sig_size == 0) {
rpmlog(RPMLOG_ERR, _("Zero length fsverity signature\n"));
rc = RPMRC_FAIL;
goto out;
}
rpmtdReset(&td);
/* RPM doesn't like new 16 bit types, so use a 32 bit tag */
algo32 = algo;
rpmtdReset(&td);
td.tag = RPMSIGTAG_VERITYSIGNATUREALGO;
td.type = RPM_INT32_TYPE;
td.data = &algo32;
td.count = 1;
headerPut(sigh, &td, HEADERPUT_DEFAULT);
rpmlog(RPMLOG_DEBUG, _("sigh size: %i\n"), headerSizeof(sigh, 0));
rc = RPMRC_OK;
out:
signatures = _free(signatures);
Fseek(fd, offset, SEEK_SET);
rpmfilesFree(files);
rpmfiFree(fi);
rpmfiFree(hfi);
rpmtsFree(ts);
return rc;
}