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-rw-r--r--lib/libalpm/signing.c301
1 files changed, 301 insertions, 0 deletions
diff --git a/lib/libalpm/signing.c b/lib/libalpm/signing.c
new file mode 100644
index 00000000..9d4fd076
--- /dev/null
+++ b/lib/libalpm/signing.c
@@ -0,0 +1,301 @@
+/*
+ * signing.c
+ *
+ * Copyright (c) 2008-2011 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 "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <locale.h> /* setlocale() */
+#include <gpgme.h>
+
+/* libalpm */
+#include "signing.h"
+#include "package.h"
+#include "util.h"
+#include "log.h"
+#include "alpm.h"
+
+#define CHECK_ERR(void) do { \
+ if(err != GPG_ERR_NO_ERROR) { goto error; } \
+ } while(0)
+
+static int gpgme_init(void)
+{
+ static int init = 0;
+ const char *version;
+ gpgme_error_t err;
+ gpgme_engine_info_t enginfo;
+
+ ALPM_LOG_FUNC;
+
+ if(init) {
+ /* we already successfully initialized the library */
+ return 0;
+ }
+
+ if(!alpm_option_get_signaturedir()) {
+ RET_ERR(PM_ERR_SIG_MISSINGDIR, 1);
+ }
+
+ /* calling gpgme_check_version() returns the current version and runs
+ * some internal library setup code */
+ version = gpgme_check_version(NULL);
+ _alpm_log(PM_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) */
+ err = gpgme_engine_check_version(GPGME_PROTOCOL_OpenPGP);
+ CHECK_ERR();
+
+ /* set and check engine information */
+ err = gpgme_set_engine_info(GPGME_PROTOCOL_OpenPGP, NULL,
+ alpm_option_get_signaturedir());
+ CHECK_ERR();
+ err = gpgme_get_engine_info(&enginfo);
+ CHECK_ERR();
+ _alpm_log(PM_LOG_DEBUG, "GPGME engine info: file=%s, home=%s\n",
+ enginfo->file_name, enginfo->home_dir);
+
+ init = 1;
+ return 0;
+
+error:
+ _alpm_log(PM_LOG_ERROR, _("GPGME error: %s\n"), gpgme_strerror(err));
+ RET_ERR(PM_ERR_GPGME, 1);
+}
+
+/**
+ * Check the PGP package signature for the given file.
+ * @param path the full path to a file
+ * @param sig PGP signature data in raw form (already decoded)
+ * @return a int value : 0 (valid), 1 (invalid), -1 (an error occured)
+ */
+int _alpm_gpgme_checksig(const char *path, const pmpgpsig_t *sig)
+{
+ int ret = 0;
+ gpgme_error_t err;
+ gpgme_ctx_t ctx;
+ gpgme_data_t filedata, sigdata;
+ gpgme_verify_result_t result;
+ gpgme_signature_t gpgsig;
+ FILE *file = NULL, *sigfile = NULL;
+
+ ALPM_LOG_FUNC;
+
+ if(!sig || !sig->data) {
+ RET_ERR(PM_ERR_SIG_UNKNOWN, -1);
+ }
+ if(!path || access(path, R_OK) != 0) {
+ RET_ERR(PM_ERR_NOT_A_FILE, -1);
+ }
+ if(gpgme_init()) {
+ /* pm_errno was set in gpgme_init() */
+ return -1;
+ }
+
+ _alpm_log(PM_LOG_DEBUG, "checking signature for %s\n", path);
+
+ memset(&ctx, 0, sizeof(ctx));
+ memset(&sigdata, 0, sizeof(sigdata));
+ memset(&filedata, 0, sizeof(filedata));
+
+ err = gpgme_new(&ctx);
+ CHECK_ERR();
+
+ /* create our necessary data objects to verify the signature */
+ file = fopen(path, "rb");
+ if(file == NULL) {
+ pm_errno = PM_ERR_NOT_A_FILE;
+ ret = -1;
+ goto error;
+ }
+ err = gpgme_data_new_from_stream(&filedata, file);
+ CHECK_ERR();
+
+ /* next create data object for the signature */
+ err = gpgme_data_new_from_mem(&sigdata, (char *)sig->data, sig->len, 0);
+ CHECK_ERR();
+
+ /* here's where the magic happens */
+ err = gpgme_op_verify(ctx, sigdata, filedata, NULL);
+ CHECK_ERR();
+ result = gpgme_op_verify_result(ctx);
+ gpgsig = result->signatures;
+ if(!gpgsig || gpgsig->next) {
+ _alpm_log(PM_LOG_ERROR, _("Unexpected number of signatures\n"));
+ ret = -1;
+ goto error;
+ }
+ _alpm_log(PM_LOG_DEBUG, "summary=%x\n", gpgsig->summary);
+ _alpm_log(PM_LOG_DEBUG, "fpr=%s\n", gpgsig->fpr);
+ _alpm_log(PM_LOG_DEBUG, "status=%d\n", gpgsig->status);
+ _alpm_log(PM_LOG_DEBUG, "timestamp=%lu\n", gpgsig->timestamp);
+ _alpm_log(PM_LOG_DEBUG, "wrong_key_usage=%u\n", gpgsig->wrong_key_usage);
+ _alpm_log(PM_LOG_DEBUG, "pka_trust=%u\n", gpgsig->pka_trust);
+ _alpm_log(PM_LOG_DEBUG, "chain_model=%u\n", gpgsig->chain_model);
+ _alpm_log(PM_LOG_DEBUG, "validity=%d\n", gpgsig->validity);
+ _alpm_log(PM_LOG_DEBUG, "validity_reason=%d\n", gpgsig->validity_reason);
+ _alpm_log(PM_LOG_DEBUG, "key=%d\n", gpgsig->pubkey_algo);
+ _alpm_log(PM_LOG_DEBUG, "hash=%d\n", gpgsig->hash_algo);
+
+ if(gpgsig->summary & GPGME_SIGSUM_VALID) {
+ /* good signature, continue */
+ _alpm_log(PM_LOG_DEBUG, _("File %s has a valid signature.\n"),
+ path);
+ } else if(gpgsig->summary & GPGME_SIGSUM_GREEN) {
+ /* 'green' signature, not sure what to do here */
+ _alpm_log(PM_LOG_WARNING, _("File %s has a green signature.\n"),
+ path);
+ } else if(gpgsig->summary & GPGME_SIGSUM_KEY_MISSING) {
+ pm_errno = PM_ERR_SIG_UNKNOWN;
+ _alpm_log(PM_LOG_WARNING, _("File %s has a signature from an unknown key.\n"),
+ path);
+ ret = -1;
+ } else {
+ /* we'll capture everything else here */
+ pm_errno = PM_ERR_SIG_INVALID;
+ _alpm_log(PM_LOG_ERROR, _("File %s has an invalid signature.\n"),
+ path);
+ ret = 1;
+ }
+
+error:
+ gpgme_data_release(sigdata);
+ gpgme_data_release(filedata);
+ gpgme_release(ctx);
+ if(sigfile) {
+ fclose(sigfile);
+ }
+ if(file) {
+ fclose(file);
+ }
+ if(err != GPG_ERR_NO_ERROR) {
+ _alpm_log(PM_LOG_ERROR, _("GPGME error: %s\n"), gpgme_strerror(err));
+ RET_ERR(PM_ERR_GPGME, -1);
+ }
+ return ret;
+}
+
+/**
+ * Load the signature from the given path into the provided struct.
+ * @param sigfile the signature to attempt to load
+ * @param pgpsig the struct to place the data in
+ *
+ * @return 0 on success, 1 on file not found, -1 on error
+ */
+int _alpm_load_signature(const char *file, pmpgpsig_t *pgpsig) {
+ struct stat st;
+ char *sigfile;
+ int ret = -1;
+
+ /* look around for a PGP signature file; load if available */
+ MALLOC(sigfile, strlen(file) + 5, RET_ERR(PM_ERR_MEMORY, -1));
+ sprintf(sigfile, "%s.sig", file);
+
+ if(access(sigfile, R_OK) == 0 && stat(sigfile, &st) == 0) {
+ FILE *f;
+ size_t bytes_read;
+
+ if(st.st_size > 4096 || (f = fopen(sigfile, "rb")) == NULL) {
+ free(sigfile);
+ return ret;
+ }
+ CALLOC(pgpsig->data, st.st_size, sizeof(unsigned char),
+ RET_ERR(PM_ERR_MEMORY, -1));
+ bytes_read = fread(pgpsig->data, sizeof(char), st.st_size, f);
+ if(bytes_read == (size_t)st.st_size) {
+ pgpsig->len = bytes_read;
+ _alpm_log(PM_LOG_DEBUG, "loaded gpg signature file, location %s\n",
+ sigfile);
+ ret = 0;
+ } else {
+ _alpm_log(PM_LOG_WARNING, _("Failed reading PGP signature file %s"),
+ sigfile);
+ FREE(pgpsig->data);
+ }
+
+ fclose(f);
+ } else {
+ _alpm_log(PM_LOG_DEBUG, "signature file %s not found\n", sigfile);
+ /* not fatal...we return a different error code here */
+ ret = 1;
+ }
+
+ free(sigfile);
+ return ret;
+}
+
+/**
+ * Determines the necessity of checking for a valid PGP signature
+ * @param db the sync database to query
+ *
+ * @return signature verification level
+ */
+pgp_verify_t _alpm_db_get_sigverify_level(pmdb_t *db)
+{
+ ALPM_LOG_FUNC;
+ ASSERT(db != NULL, RET_ERR(PM_ERR_DB_NULL, PM_PGP_VERIFY_UNKNOWN));
+
+ if(db->pgp_verify != PM_PGP_VERIFY_UNKNOWN) {
+ return db->pgp_verify;
+ } else {
+ return alpm_option_get_default_sigverify();
+ }
+}
+
+/**
+ * Check the PGP package signature for the given package file.
+ * @param pkg the package to check
+ * @return a int value : 0 (valid), 1 (invalid), -1 (an error occurred)
+ */
+int SYMEXPORT alpm_pkg_check_pgp_signature(pmpkg_t *pkg)
+{
+ ALPM_LOG_FUNC;
+ ASSERT(pkg != NULL, return 0);
+
+ return _alpm_gpgme_checksig(alpm_pkg_get_filename(pkg),
+ alpm_pkg_get_pgpsig(pkg));
+}
+
+/**
+ * Check the PGP package signature for the given database.
+ * @param db the database to check
+ * @return a int value : 0 (valid), 1 (invalid), -1 (an error occurred)
+ */
+int SYMEXPORT alpm_db_check_pgp_signature(pmdb_t *db)
+{
+ ALPM_LOG_FUNC;
+ ASSERT(db != NULL, return 0);
+
+ return _alpm_gpgme_checksig(_alpm_db_path(db),
+ _alpm_db_pgpsig(db));
+}
+
+/* vim: set ts=2 sw=2 noet: */

Copyright © 2002-2022 Judd Vinet and Aaron Griffin. Copyright © 2022 Erich Eckner.
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