moparisthebest
/
pacman
mirror of https://github.com/moparisthebest/pacman
1
0
Fork 0
Code Issues Releases Wiki Activity
pacman/lib/libalpm/signing.c

1074 lines
31 KiB
C
Raw Blame History

/*
* signing.c
*
* Copyright (c) 2008-2014 Pacman Development Team <pacman-dev@archlinux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_LIBGPGME
#include <locale.h> /* setlocale() */
#include <gpgme.h>
#endif
/* libalpm */
#include "signing.h"
#include "package.h"
#include "base64.h"
#include "util.h"
#include "log.h"
#include "alpm.h"
#include "handle.h"
/**
* Decode a loaded signature in base64 form.
* @param base64_data the signature to attempt to decode
* @param data the decoded data; must be freed by the caller
* @param data_len the length of the returned data
* @return 0 on success, -1 on failure to properly decode
*/
int SYMEXPORT alpm_decode_signature(const char *base64_data,
unsigned char **data, size_t *data_len)
{
size_t len = strlen(base64_data);
unsigned char *usline = (unsigned char *)base64_data;
/* reasonable allocation of expected length is 3/4 of encoded length */
size_t destlen = len * 3 / 4;
MALLOC(*data, destlen, goto error);
if(base64_decode(*data, &destlen, usline, len)) {
free(*data);
goto error;
}
*data_len = destlen;
return 0;
error:
*data = NULL;
*data_len = 0;
return -1;
}
#ifdef HAVE_LIBGPGME
#define CHECK_ERR(void) do { \
if(gpg_err_code(gpg_err) != GPG_ERR_NO_ERROR) { goto gpg_error; } \
} while(0)
/**
* Return a statically allocated validity string based on the GPGME validity
* code. This is mainly for debug purposes and is not translated.
* @param validity a validity code returned by GPGME
* @return a string such as "marginal"
*/
static const char *string_validity(gpgme_validity_t validity)
{
switch(validity) {
case GPGME_VALIDITY_UNKNOWN:
return "unknown";
case GPGME_VALIDITY_UNDEFINED:
return "undefined";
case GPGME_VALIDITY_NEVER:
return "never";
case GPGME_VALIDITY_MARGINAL:
return "marginal";
case GPGME_VALIDITY_FULL:
return "full";
case GPGME_VALIDITY_ULTIMATE:
return "ultimate";
}
return "???";
}
static void sigsum_test_bit(gpgme_sigsum_t sigsum, alpm_list_t **summary,
gpgme_sigsum_t bit, const char *value)
{
if(sigsum & bit) {
*summary = alpm_list_add(*summary, (void *)value);
}
}
/**
* Calculate a set of strings to represent the given GPGME signature summary
* value. This is a bitmask so you may get any number of strings back.
* @param sigsum a GPGME signature summary bitmask
* @return the list of signature summary strings
*/
static alpm_list_t *list_sigsum(gpgme_sigsum_t sigsum)
{
alpm_list_t *summary = NULL;
/* The docs say this can be a bitmask...not sure I believe it, but we'll code
* for it anyway and show all possible flags in the returned string. */
/* The signature is fully valid. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_VALID, "valid");
/* The signature is good. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_GREEN, "green");
/* The signature is bad. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_RED, "red");
/* One key has been revoked. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_KEY_REVOKED, "key revoked");
/* One key has expired. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_KEY_EXPIRED, "key expired");
/* The signature has expired. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_SIG_EXPIRED, "sig expired");
/* Can't verify: key missing. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_KEY_MISSING, "key missing");
/* CRL not available. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_CRL_MISSING, "crl missing");
/* Available CRL is too old. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_CRL_TOO_OLD, "crl too old");
/* A policy was not met. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_BAD_POLICY, "bad policy");
/* A system error occurred. */
sigsum_test_bit(sigsum, &summary, GPGME_SIGSUM_SYS_ERROR, "sys error");
/* Fallback case */
if(!sigsum) {
summary = alpm_list_add(summary, (void *)"(empty)");
}
return summary;
}
/**
* Initialize the GPGME library.
* This can be safely called multiple times; however it is not thread-safe.
* @param handle the context handle
* @return 0 on success, -1 on error
*/
static int init_gpgme(alpm_handle_t *handle)
{
static int init = 0;
const char *version, *sigdir;
gpgme_error_t gpg_err;
gpgme_engine_info_t enginfo;
if(init) {
/* we already successfully initialized the library */
return 0;
}
sigdir = handle->gpgdir;
if(_alpm_access(handle, sigdir, "pubring.gpg", R_OK)
|| _alpm_access(handle, sigdir, "trustdb.gpg", R_OK)) {
handle->pm_errno = ALPM_ERR_NOT_A_FILE;
_alpm_log(handle, ALPM_LOG_DEBUG, "Signature verification will fail!\n");
_alpm_log(handle, ALPM_LOG_WARNING,
_("Public keyring not found; have you run '%s'?\n"),
"pacman-key --init");
}
/* calling gpgme_check_version() returns the current version and runs
* some internal library setup code */
version = gpgme_check_version(NULL);
_alpm_log(handle, ALPM_LOG_DEBUG, "GPGME version: %s\n", version);
gpgme_set_locale(NULL, LC_CTYPE, setlocale(LC_CTYPE, NULL));
#ifdef LC_MESSAGES
gpgme_set_locale(NULL, LC_MESSAGES, setlocale(LC_MESSAGES, NULL));
#endif
/* NOTE:
* The GPGME library installs a SIGPIPE signal handler automatically if
* the default signal hander is in use. The only time we set a handler
* for SIGPIPE is in dload.c, and we reset it when we are done. Given that
* we do this, we can let GPGME do its automagic. However, if we install
* a library-wide SIGPIPE handler, we will have to be careful.
*/
/* check for OpenPGP support (should be a no-brainer, but be safe) */
gpg_err = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
CHECK_ERR();
/* set and check engine information */
gpg_err = gpgme_set_engine_info(GPGME_PROTOCOL_OpenPGP, NULL, sigdir);
CHECK_ERR();
gpg_err = gpgme_get_engine_info(&enginfo);
CHECK_ERR();
_alpm_log(handle, ALPM_LOG_DEBUG, "GPGME engine info: file=%s, home=%s\n",
enginfo->file_name, enginfo->home_dir);
init = 1;
return 0;
gpg_error:
_alpm_log(handle, ALPM_LOG_ERROR, _("GPGME error: %s\n"), gpgme_strerror(gpg_err));
RET_ERR(handle, ALPM_ERR_GPGME, -1);
}
/**
* Determine if we have a key is known in our local keyring.
* @param handle the context handle
* @param fpr the fingerprint key ID to look up
* @return 1 if key is known, 0 if key is unknown, -1 on error
*/
int _alpm_key_in_keychain(alpm_handle_t *handle, const char *fpr)
{
gpgme_error_t gpg_err;
gpgme_ctx_t ctx;
gpgme_key_t key;
int ret = -1;
if(init_gpgme(handle)) {
/* pm_errno was set in gpgme_init() */
goto error;
}
memset(&ctx, 0, sizeof(ctx));
gpg_err = gpgme_new(&ctx);
CHECK_ERR();
_alpm_log(handle, ALPM_LOG_DEBUG, "looking up key %s locally\n", fpr);
gpg_err = gpgme_get_key(ctx, fpr, &key, 0);
if(gpg_err_code(gpg_err) == GPG_ERR_EOF) {
_alpm_log(handle, ALPM_LOG_DEBUG, "key lookup failed, unknown key\n");
ret = 0;
} else if(gpg_err_code(gpg_err) == GPG_ERR_NO_ERROR) {
_alpm_log(handle, ALPM_LOG_DEBUG, "key lookup success, key exists\n");
ret = 1;
} else {
_alpm_log(handle, ALPM_LOG_DEBUG, "gpg error: %s\n", gpgme_strerror(gpg_err));
}
gpgme_key_unref(key);
gpg_error:
gpgme_release(ctx);
error:
return ret;
}
/**
* Search for a GPG key in a remote location.
* This requires GPGME to call the gpg binary and have a keyserver previously
* defined in a gpg.conf configuration file.
* @param handle the context handle
* @param fpr the fingerprint key ID to look up
* @param pgpkey storage location for the given key if found
* @return 1 on success, 0 on key not found, -1 on error
*/
static int key_search(alpm_handle_t *handle, const char *fpr,
alpm_pgpkey_t *pgpkey)
{
gpgme_error_t gpg_err;
gpgme_ctx_t ctx;
gpgme_keylist_mode_t mode;
gpgme_key_t key;
int ret = -1;
size_t fpr_len;
char *full_fpr;
/* gpg2 goes full retard here. For key searches ONLY, we need to prefix the
* key fingerprint with 0x, or the lookup will fail. */
fpr_len = strlen(fpr);
MALLOC(full_fpr, fpr_len + 3, RET_ERR(handle, ALPM_ERR_MEMORY, -1));
sprintf(full_fpr, "0x%s", fpr);
memset(&ctx, 0, sizeof(ctx));
gpg_err = gpgme_new(&ctx);
CHECK_ERR();
mode = gpgme_get_keylist_mode(ctx);
/* using LOCAL and EXTERN together doesn't work for GPG 1.X. Ugh. */
mode &= ~GPGME_KEYLIST_MODE_LOCAL;
mode |= GPGME_KEYLIST_MODE_EXTERN;
gpg_err = gpgme_set_keylist_mode(ctx, mode);
CHECK_ERR();
_alpm_log(handle, ALPM_LOG_DEBUG, "looking up key %s remotely\n", fpr);
gpg_err = gpgme_get_key(ctx, full_fpr, &key, 0);
if(gpg_err_code(gpg_err) == GPG_ERR_EOF) {
_alpm_log(handle, ALPM_LOG_DEBUG, "key lookup failed, unknown key\n");
/* Try an alternate lookup using the 8 character fingerprint value, since
* busted-ass keyservers can't support lookups using subkeys with the full
* value as of now. This is why 2012 is not the year of PGP encryption. */
if(fpr_len > 8) {
const char *short_fpr = memcpy(&full_fpr[fpr_len - 8], "0x", 2);
_alpm_log(handle, ALPM_LOG_DEBUG,
"looking up key %s remotely\n", short_fpr);
gpg_err = gpgme_get_key(ctx, short_fpr, &key, 0);
if(gpg_err_code(gpg_err) == GPG_ERR_EOF) {
_alpm_log(handle, ALPM_LOG_DEBUG, "key lookup failed, unknown key\n");
ret = 0;
}
} else {
ret = 0;
}
}
CHECK_ERR();
/* should only get here if key actually exists */
pgpkey->data = key;
if(key->subkeys->fpr) {
pgpkey->fingerprint = key->subkeys->fpr;
} else if(key->subkeys->keyid) {
pgpkey->fingerprint = key->subkeys->keyid;
}
pgpkey->uid = key->uids->uid;
pgpkey->name = key->uids->name;
pgpkey->email = key->uids->email;
pgpkey->created = key->subkeys->timestamp;
pgpkey->expires = key->subkeys->expires;
pgpkey->length = key->subkeys->length;
pgpkey->revoked = key->subkeys->revoked;
switch(key->subkeys->pubkey_algo) {
case GPGME_PK_RSA:
case GPGME_PK_RSA_E:
case GPGME_PK_RSA_S:
pgpkey->pubkey_algo = 'R';
break;
case GPGME_PK_DSA:
pgpkey->pubkey_algo = 'D';
break;
case GPGME_PK_ELG_E:
case GPGME_PK_ELG:
case GPGME_PK_ECDSA:
case GPGME_PK_ECDH:
pgpkey->pubkey_algo = 'E';
break;
}
ret = 1;
gpg_error:
if(ret != 1) {
_alpm_log(handle, ALPM_LOG_DEBUG, "gpg error: %s\n", gpgme_strerror(gpg_err));
}
free(full_fpr);
gpgme_release(ctx);
return ret;
}
/**
* Import a key into the local keyring.
* @param handle the context handle
* @param key the key to import, likely retrieved from #key_search
* @return 0 on success, -1 on error
*/
static int key_import(alpm_handle_t *handle, alpm_pgpkey_t *key)
{
gpgme_error_t gpg_err;
gpgme_ctx_t ctx;
gpgme_key_t keys[2];
gpgme_import_result_t result;
int ret = -1;
if(_alpm_access(handle, handle->gpgdir, "pubring.gpg", W_OK)) {
/* no chance of import succeeding if pubring isn't writable */
_alpm_log(handle, ALPM_LOG_ERROR, _("keyring is not writable\n"));
return -1;
}
memset(&ctx, 0, sizeof(ctx));
gpg_err = gpgme_new(&ctx);
CHECK_ERR();
_alpm_log(handle, ALPM_LOG_DEBUG, "importing key\n");
keys[0] = key->data;
keys[1] = NULL;
gpg_err = gpgme_op_import_keys(ctx, keys);
CHECK_ERR();
result = gpgme_op_import_result(ctx);
CHECK_ERR();
/* we know we tried to import exactly one key, so check for this */
if(result->considered != 1 || !result->imports) {
_alpm_log(handle, ALPM_LOG_DEBUG, "could not import key, 0 results\n");
ret = -1;
} else if(result->imports->result != GPG_ERR_NO_ERROR) {
_alpm_log(handle, ALPM_LOG_DEBUG, "gpg error: %s\n", gpgme_strerror(gpg_err));
ret = -1;
} else {
ret = 0;
}
gpg_error:
gpgme_release(ctx);
return ret;
}
/**
* Import a key defined by a fingerprint into the local keyring.
* @param handle the context handle
* @param fpr the fingerprint key ID to import
* @return 0 on success, -1 on error
*/
int _alpm_key_import(alpm_handle_t *handle, const char *fpr)
{
int answer = 0, ret = -1;
alpm_pgpkey_t fetch_key;
memset(&fetch_key, 0, sizeof(fetch_key));
if(key_search(handle, fpr, &fetch_key) == 1) {
_alpm_log(handle, ALPM_LOG_DEBUG,
"unknown key, found %s on keyserver\n", fetch_key.uid);
if(!_alpm_access(handle, handle->gpgdir, "pubring.gpg", W_OK)) {
QUESTION(handle, ALPM_QUESTION_IMPORT_KEY,
&fetch_key, NULL, NULL, &answer);
if(answer) {
if(key_import(handle, &fetch_key) == 0) {
ret = 0;
} else {
_alpm_log(handle, ALPM_LOG_ERROR,
_("key \"%s\" could not be imported\n"), fetch_key.uid);
}
}
} else {
/* keyring directory was not writable, so we don't even try */
_alpm_log(handle, ALPM_LOG_WARNING,
_("key %s, \"%s\" found on keyserver, keyring is not writable\n"),
fetch_key.fingerprint, fetch_key.uid);
}
} else {
_alpm_log(handle, ALPM_LOG_ERROR,
_("key \"%s\" could not be looked up remotely\n"), fpr);
}
gpgme_key_unref(fetch_key.data);
return ret;
}
/**
* Check the PGP signature for the given file path.
* If base64_sig is provided, it will be used as the signature data after
* decoding. If base64_sig is NULL, expect a signature file next to path
* (e.g. "%s.sig").
*
* The return value will be 0 if nothing abnormal happened during the signature
* check, and -1 if an error occurred while checking signatures or if a
* signature could not be found; pm_errno will be set. Note that "abnormal"
* does not include a failed signature; the value in siglist should be checked
* to determine if the signature(s) are good.
* @param handle the context handle
* @param path the full path to a file
* @param base64_sig optional PGP signature data in base64 encoding
* @param siglist a pointer to storage for signature results
* @return 0 in normal cases, -1 if the something failed in the check process
*/
int _alpm_gpgme_checksig(alpm_handle_t *handle, const char *path,
const char *base64_sig, alpm_siglist_t *siglist)
{
int ret = -1, sigcount;
gpgme_error_t gpg_err = 0;
gpgme_ctx_t ctx;
gpgme_data_t filedata, sigdata;
gpgme_verify_result_t verify_result;
gpgme_signature_t gpgsig;
char *sigpath = NULL;
unsigned char *decoded_sigdata = NULL;
FILE *file = NULL, *sigfile = NULL;
if(!path || _alpm_access(handle, NULL, path, R_OK) != 0) {
RET_ERR(handle, ALPM_ERR_NOT_A_FILE, -1);
}
if(!siglist) {
RET_ERR(handle, ALPM_ERR_WRONG_ARGS, -1);
}
siglist->count = 0;
if(!base64_sig) {
sigpath = _alpm_sigpath(handle, path);
if(_alpm_access(handle, NULL, sigpath, R_OK) != 0
|| (sigfile = fopen(sigpath, "rb")) == NULL) {
_alpm_log(handle, ALPM_LOG_DEBUG, "sig path %s could not be opened\n",
sigpath);
handle->pm_errno = ALPM_ERR_SIG_MISSING;
goto error;
}
}
/* does the file we are verifying exist? */
file = fopen(path, "rb");
if(file == NULL) {
handle->pm_errno = ALPM_ERR_NOT_A_FILE;
goto error;
}
if(init_gpgme(handle)) {
/* pm_errno was set in gpgme_init() */
goto error;
}
_alpm_log(handle, ALPM_LOG_DEBUG, "checking signature for %s\n", path);
memset(&ctx, 0, sizeof(ctx));
memset(&sigdata, 0, sizeof(sigdata));
memset(&filedata, 0, sizeof(filedata));
gpg_err = gpgme_new(&ctx);
CHECK_ERR();
/* create our necessary data objects to verify the signature */
gpg_err = gpgme_data_new_from_stream(&filedata, file);
CHECK_ERR();
/* next create data object for the signature */
if(base64_sig) {
/* memory-based, we loaded it from a sync DB */
size_t data_len;
int decode_ret = alpm_decode_signature(base64_sig,
&decoded_sigdata, &data_len);
if(decode_ret) {
handle->pm_errno = ALPM_ERR_SIG_INVALID;
goto gpg_error;
}
gpg_err = gpgme_data_new_from_mem(&sigdata,
(char *)decoded_sigdata, data_len, 0);
} else {
/* file-based, it is on disk */
gpg_err = gpgme_data_new_from_stream(&sigdata, sigfile);
}
CHECK_ERR();
/* here's where the magic happens */
gpg_err = gpgme_op_verify(ctx, sigdata, filedata, NULL);
CHECK_ERR();
verify_result = gpgme_op_verify_result(ctx);
CHECK_ERR();
if(!verify_result || !verify_result->signatures) {
_alpm_log(handle, ALPM_LOG_DEBUG, "no signatures returned\n");
handle->pm_errno = ALPM_ERR_SIG_MISSING;
goto gpg_error;
}
for(gpgsig = verify_result->signatures, sigcount = 0;
gpgsig; gpgsig = gpgsig->next, sigcount++);
_alpm_log(handle, ALPM_LOG_DEBUG, "%d signatures returned\n", sigcount);
CALLOC(siglist->results, sigcount, sizeof(alpm_sigresult_t),
handle->pm_errno = ALPM_ERR_MEMORY; goto gpg_error);
siglist->count = sigcount;
for(gpgsig = verify_result->signatures, sigcount = 0; gpgsig;
gpgsig = gpgsig->next, sigcount++) {
alpm_list_t *summary_list, *summary;
alpm_sigstatus_t status;
alpm_sigvalidity_t validity;
gpgme_key_t key;
alpm_sigresult_t *result;
_alpm_log(handle, ALPM_LOG_DEBUG, "fingerprint: %s\n", gpgsig->fpr);
summary_list = list_sigsum(gpgsig->summary);
for(summary = summary_list; summary; summary = summary->next) {
_alpm_log(handle, ALPM_LOG_DEBUG, "summary: %s\n", (const char *)summary->data);
}
alpm_list_free(summary_list);
_alpm_log(handle, ALPM_LOG_DEBUG, "status: %s\n", gpgme_strerror(gpgsig->status));
_alpm_log(handle, ALPM_LOG_DEBUG, "timestamp: %lu\n", gpgsig->timestamp);
if((time_t)gpgsig->timestamp > time(NULL)) {
_alpm_log(handle, ALPM_LOG_DEBUG,
"signature timestamp is greater than system time.\n");
}
_alpm_log(handle, ALPM_LOG_DEBUG, "exp_timestamp: %lu\n", gpgsig->exp_timestamp);
_alpm_log(handle, ALPM_LOG_DEBUG, "validity: %s; reason: %s\n",
string_validity(gpgsig->validity),
gpgme_strerror(gpgsig->validity_reason));
result = siglist->results + sigcount;
gpg_err = gpgme_get_key(ctx, gpgsig->fpr, &key, 0);
if(gpg_err_code(gpg_err) == GPG_ERR_EOF) {
_alpm_log(handle, ALPM_LOG_DEBUG, "key lookup failed, unknown key\n");
gpg_err = GPG_ERR_NO_ERROR;
/* we dupe the fpr in this case since we have no key to point at */
STRDUP(result->key.fingerprint, gpgsig->fpr,
handle->pm_errno = ALPM_ERR_MEMORY; goto gpg_error);
} else {
CHECK_ERR();
if(key->uids) {
result->key.data = key;
result->key.fingerprint = key->subkeys->fpr;
result->key.uid = key->uids->uid;
result->key.name = key->uids->name;
result->key.email = key->uids->email;
result->key.created = key->subkeys->timestamp;
result->key.expires = key->subkeys->expires;
_alpm_log(handle, ALPM_LOG_DEBUG,
"key: %s, %s, owner_trust %s, disabled %d\n",
key->subkeys->fpr, key->uids->uid,
string_validity(key->owner_trust), key->disabled);
}
}
switch(gpg_err_code(gpgsig->status)) {
/* good cases */
case GPG_ERR_NO_ERROR:
status = ALPM_SIGSTATUS_VALID;
break;
case GPG_ERR_KEY_EXPIRED:
status = ALPM_SIGSTATUS_KEY_EXPIRED;
break;
/* bad cases */
case GPG_ERR_SIG_EXPIRED:
status = ALPM_SIGSTATUS_SIG_EXPIRED;
break;
case GPG_ERR_NO_PUBKEY:
status = ALPM_SIGSTATUS_KEY_UNKNOWN;
break;
case GPG_ERR_BAD_SIGNATURE:
default:
status = ALPM_SIGSTATUS_INVALID;
break;
}
/* special case: key disabled is not returned in above status code */
if(result->key.data && key->disabled) {
status = ALPM_SIGSTATUS_KEY_DISABLED;
}
switch(gpgsig->validity) {
case GPGME_VALIDITY_ULTIMATE:
case GPGME_VALIDITY_FULL:
validity = ALPM_SIGVALIDITY_FULL;
break;
case GPGME_VALIDITY_MARGINAL:
validity = ALPM_SIGVALIDITY_MARGINAL;
break;
case GPGME_VALIDITY_NEVER:
validity = ALPM_SIGVALIDITY_NEVER;
break;
case GPGME_VALIDITY_UNKNOWN:
case GPGME_VALIDITY_UNDEFINED:
default:
validity = ALPM_SIGVALIDITY_UNKNOWN;
break;
}
result->status = status;
result->validity = validity;
}
ret = 0;
gpg_error:
gpgme_data_release(sigdata);
gpgme_data_release(filedata);
gpgme_release(ctx);
error:
if(sigfile) {
fclose(sigfile);
}
if(file) {
fclose(file);
}
FREE(sigpath);
FREE(decoded_sigdata);
if(gpg_err_code(gpg_err) != GPG_ERR_NO_ERROR) {
_alpm_log(handle, ALPM_LOG_ERROR, _("GPGME error: %s\n"), gpgme_strerror(gpg_err));
RET_ERR(handle, ALPM_ERR_GPGME, -1);
}
return ret;
}
#else /* HAVE_LIBGPGME */
int _alpm_key_in_keychain(alpm_handle_t UNUSED *handle, const char UNUSED *fpr)
{
return -1;
}
int _alpm_key_import(alpm_handle_t UNUSED *handle, const char UNUSED *fpr)
{
return -1;
}
int _alpm_gpgme_checksig(alpm_handle_t UNUSED *handle, const char UNUSED *path,
const char UNUSED *base64_sig, alpm_siglist_t UNUSED *siglist)
{
return -1;
}
#endif /* HAVE_LIBGPGME */
/**
* Form a signature path given a file path.
* Caller must free the result.
* @param handle the context handle
* @param path the full path to a file
* @return the path with '.sig' appended, NULL on errors
*/
char *_alpm_sigpath(alpm_handle_t *handle, const char *path)
{
char *sigpath;
size_t len;
if(!path) {
return NULL;
}
len = strlen(path) + 5;
CALLOC(sigpath, len, sizeof(char), RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
sprintf(sigpath, "%s.sig", path);
return sigpath;
}
/**
* Helper for checking the PGP signature for the given file path.
* This wraps #_alpm_gpgme_checksig in a slightly friendlier manner to simplify
* handling of optional signatures and marginal/unknown trust levels and
* handling the correct error code return values.
* @param handle the context handle
* @param path the full path to a file
* @param base64_sig optional PGP signature data in base64 encoding
* @param optional whether signatures are optional (e.g., missing OK)
* @param marginal whether signatures with marginal trust are acceptable
* @param unknown whether signatures with unknown trust are acceptable
* @param sigdata a pointer to storage for signature results
* @return 0 on success, -1 on error (consult pm_errno or sigdata)
*/
int _alpm_check_pgp_helper(alpm_handle_t *handle, const char *path,
const char *base64_sig, int optional, int marginal, int unknown,
alpm_siglist_t **sigdata)
{
alpm_siglist_t *siglist;
int ret;
CALLOC(siglist, 1, sizeof(alpm_siglist_t),
RET_ERR(handle, ALPM_ERR_MEMORY, -1));
ret = _alpm_gpgme_checksig(handle, path, base64_sig, siglist);
if(ret && handle->pm_errno == ALPM_ERR_SIG_MISSING) {
if(optional) {
_alpm_log(handle, ALPM_LOG_DEBUG, "missing optional signature\n");
handle->pm_errno = 0;
ret = 0;
} else {
_alpm_log(handle, ALPM_LOG_DEBUG, "missing required signature\n");
/* ret will already be -1 */
}
} else if(ret) {
_alpm_log(handle, ALPM_LOG_DEBUG, "signature check failed\n");
/* ret will already be -1 */
} else {
size_t num;
for(num = 0; !ret && num < siglist->count; num++) {
switch(siglist->results[num].status) {
case ALPM_SIGSTATUS_VALID:
case ALPM_SIGSTATUS_KEY_EXPIRED:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature is valid\n");
switch(siglist->results[num].validity) {
case ALPM_SIGVALIDITY_FULL:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature is fully trusted\n");
break;
case ALPM_SIGVALIDITY_MARGINAL:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature is marginal trust\n");
if(!marginal) {
ret = -1;
}
break;
case ALPM_SIGVALIDITY_UNKNOWN:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature is unknown trust\n");
if(!unknown) {
ret = -1;
}
break;
case ALPM_SIGVALIDITY_NEVER:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature should never be trusted\n");
ret = -1;
break;
}
break;
case ALPM_SIGSTATUS_SIG_EXPIRED:
case ALPM_SIGSTATUS_KEY_UNKNOWN:
case ALPM_SIGSTATUS_KEY_DISABLED:
case ALPM_SIGSTATUS_INVALID:
_alpm_log(handle, ALPM_LOG_DEBUG, "signature is not valid\n");
ret = -1;
break;
}
}
}
if(sigdata) {
*sigdata = siglist;
} else {
alpm_siglist_cleanup(siglist);
free(siglist);
}
return ret;
}
/**
* Examine a signature result list and take any appropriate or necessary
* actions. This may include asking the user to import a key or simply printing
* helpful failure messages so the user can take action out of band.
* @param handle the context handle
* @param identifier a friendly name for the signed resource; usually a
* database or package name
* @param siglist a pointer to storage for signature results
* @param optional whether signatures are optional (e.g., missing OK)
* @param marginal whether signatures with marginal trust are acceptable
* @param unknown whether signatures with unknown trust are acceptable
* @return 0 if all signatures are OK, -1 on errors, 1 if we should retry the
* validation process
*/
int _alpm_process_siglist(alpm_handle_t *handle, const char *identifier,
alpm_siglist_t *siglist, int optional, int marginal, int unknown)
{
size_t i;
int retry = 0;
if(!optional && siglist->count == 0) {
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: missing required signature\n"), identifier);
}
for(i = 0; i < siglist->count; i++) {
alpm_sigresult_t *result = siglist->results + i;
const char *name = result->key.uid ? result->key.uid : result->key.fingerprint;
switch(result->status) {
case ALPM_SIGSTATUS_VALID:
case ALPM_SIGSTATUS_KEY_EXPIRED:
switch(result->validity) {
case ALPM_SIGVALIDITY_FULL:
break;
case ALPM_SIGVALIDITY_MARGINAL:
if(!marginal) {
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature from \"%s\" is marginal trust\n"),
identifier, name);
/* QUESTION(handle, ALPM_QUESTION_EDIT_KEY_TRUST, &result->key, NULL, NULL, &answer); */
}
break;
case ALPM_SIGVALIDITY_UNKNOWN:
if(!unknown) {
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature from \"%s\" is unknown trust\n"),
identifier, name);
/* QUESTION(handle, ALPM_QUESTION_EDIT_KEY_TRUST, &result->key, NULL, NULL, &answer); */
}
break;
case ALPM_SIGVALIDITY_NEVER:
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature from \"%s\" should never be trusted\n"),
identifier, name);
break;
}
break;
case ALPM_SIGSTATUS_KEY_UNKNOWN:
/* ensure this key is still actually unknown; we may have imported it
* on an earlier call to this function. */
if(_alpm_key_in_keychain(handle, result->key.fingerprint) == 1) {
break;
}
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: key \"%s\" is unknown\n"), identifier, name);
if(_alpm_key_import(handle, result->key.fingerprint) == 0) {
retry = 1;
}
break;
case ALPM_SIGSTATUS_KEY_DISABLED:
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: key \"%s\" is disabled\n"), identifier, name);
break;
case ALPM_SIGSTATUS_SIG_EXPIRED:
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature from \"%s\" is expired\n"), identifier, name);
break;
case ALPM_SIGSTATUS_INVALID:
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature from \"%s\" is invalid\n"),
identifier, name);
break;
}
}
return retry;
}
/**
* Check the PGP signature for the given package file.
* @param pkg the package to check
* @param siglist a pointer to storage for signature results
* @return a int value : 0 (valid), 1 (invalid), -1 (an error occurred)
*/
int SYMEXPORT alpm_pkg_check_pgp_signature(alpm_pkg_t *pkg,
alpm_siglist_t *siglist)
{
ASSERT(pkg != NULL, return -1);
ASSERT(siglist != NULL, RET_ERR(pkg->handle, ALPM_ERR_WRONG_ARGS, -1));
pkg->handle->pm_errno = 0;
return _alpm_gpgme_checksig(pkg->handle, pkg->filename,
pkg->base64_sig, siglist);
}
/**
* Check the PGP signature for the given database.
* @param db the database to check
* @param siglist a pointer to storage for signature results
* @return a int value : 0 (valid), 1 (invalid), -1 (an error occurred)
*/
int SYMEXPORT alpm_db_check_pgp_signature(alpm_db_t *db,
alpm_siglist_t *siglist)
{
ASSERT(db != NULL, return -1);
ASSERT(siglist != NULL, RET_ERR(db->handle, ALPM_ERR_WRONG_ARGS, -1));
db->handle->pm_errno = 0;
return _alpm_gpgme_checksig(db->handle, _alpm_db_path(db), NULL, siglist);
}
/**
* Clean up and free a signature result list.
* Note that this does not free the siglist object itself in case that
* was allocated on the stack; this is the responsibility of the caller.
* @param siglist a pointer to storage for signature results
* @return 0 on success, -1 on error
*/
int SYMEXPORT alpm_siglist_cleanup(alpm_siglist_t *siglist)
{
ASSERT(siglist != NULL, return -1);
size_t num;
for(num = 0; num < siglist->count; num++) {
alpm_sigresult_t *result = siglist->results + num;
if(result->key.data) {
#ifdef HAVE_LIBGPGME
gpgme_key_unref(result->key.data);
#endif
} else {
free(result->key.fingerprint);
}
}
if(siglist->count) {
free(siglist->results);
}
siglist->results = NULL;
siglist->count = 0;
return 0;
}
/**
* Extract the Issuer Key ID from a signature
* @param sig PGP signature
* @param len length of signature
* @param keys a pointer to storage for key IDs
* @return 0 on success, -1 on error
*/
int SYMEXPORT alpm_extract_keyid(alpm_handle_t *handle, const char *identifier,
const unsigned char *sig, const size_t len, alpm_list_t **keys)
{
size_t pos, spos, blen, hlen, ulen, slen;
pos = 0;
while(pos < len) {
if(!(sig[pos] & 0x80)) {
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature format error"), identifier);
return -1;
}
if(sig[pos] & 0x40) {
/* "new" packet format is not supported */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: unsupported signature format"), identifier);
return -1;
}
if(((sig[pos] & 0x3f) >> 2) != 2) {
/* signature is not a "Signature Packet" */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature format error"), identifier);
return -1;
}
switch(sig[pos] & 0x03) {
case 0:
blen = sig[pos + 1];
pos = pos + 2;
break;
case 1:
blen = (sig[pos + 1] << 8) | sig[pos + 2];
pos = pos + 3;
break;
case 2:
blen = (sig[pos + 1] << 24) | (sig[pos + 2] << 16) | (sig[pos + 3] << 8) | sig[pos + 4];
pos = pos + 5;
break;
case 3:
/* partial body length not supported */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: unsupported signature format"), identifier);
return -1;
}
if(sig[pos] != 4) {
/* only support version 4 signature packet format */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: unsupported signature format"), identifier);
return -1;
}
if(sig[pos + 1] != 0x00) {
/* not a signature of a binary document */
_alpm_log(handle, ALPM_LOG_ERROR,
_("%s: signature format error"), identifier);
return -1;
}
pos = pos + 4;
hlen = (sig[pos] << 8) | sig[pos + 1];
pos = pos + hlen + 2;
ulen = (sig[pos] << 8) | sig[pos + 1];
pos = pos + 2;
spos = pos;
while(spos < pos + ulen) {
if(sig[spos] < 192) {
slen = sig[spos];
spos = spos + 1;
} else if(sig[spos] < 255) {
slen = (sig[spos] << 8) | sig[spos + 1];
spos = spos + 2;
} else {
slen = (sig[spos + 1] << 24) | (sig[spos + 2] << 16) | (sig[spos + 3] << 8) | sig[spos + 4];
spos = spos + 5;
}
if(sig[spos] == 16) {
/* issuer key ID */
char key[17];
size_t i;
for (i = 0; i < 8; i++) {
sprintf(&key[i * 2], "%02X", sig[spos + i + 1]);
}
*keys = alpm_list_add(*keys, strdup(key));
break;
}
spos = spos + slen;
}
pos = pos + (blen - hlen - 8);
}
return 0;
}
/* vim: set noet: */
Reference in New Issue View Git Blame Copy Permalink