4 files changed, 64 insertions, 5 deletions

diff --git a/lib/libalpm/alpm.h b/lib/libalpm/alpm.h
index 715e502a..eb2eff88 100644
--- a/lib/libalpm/alpm.h
+++ b/lib/libalpm/alpm.h
@@ -357,9 +357,12 @@ alpm_list_t *alpm_option_get_syncdbs(pmhandle_t *handle);
 /** Register a sync database of packages.
  * @param handle the context handle
  * @param treename the name of the sync repository
+ * @param check_sig what level of signature checking to perform on the
+ * database; note that this must be a '.sig' file type verification
  * @return a pmdb_t* on success (the value), NULL on error
  */
-pmdb_t *alpm_db_register_sync(pmhandle_t *handle, const char *treename);
+pmdb_t *alpm_db_register_sync(pmhandle_t *handle, const char *treename,
+		pgp_verify_t check_sig);
 
 /** Unregister a package database.
  * @param db pointer to the package database to unregister
diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
index e5fc6a70..2cf90544 100644
--- a/lib/libalpm/be_sync.c
+++ b/lib/libalpm/be_sync.c
@@ -20,7 +20,9 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 /* libarchive */
 #include <archive.h>
@@ -65,6 +67,37 @@ static char *get_sync_dir(pmhandle_t *handle)
 	return syncpath;
 }
 
+static int sync_db_validate(pmdb_t *db)
+{
+	/* this takes into account the default verification level if UNKNOWN
+	 * was assigned to this db */
+	pgp_verify_t check_sig = _alpm_db_get_sigverify_level(db);
+
+	if(check_sig != PM_PGP_VERIFY_NEVER) {
+		int ret;
+		const char *dbpath = _alpm_db_path(db);
+		if(!dbpath) {
+			/* pm_errno set in _alpm_db_path() */
+			return -1;
+		}
+
+		/* we can skip any validation if the database doesn't exist */
+		if(access(dbpath, R_OK) != 0 && errno == ENOENT) {
+			return 0;
+		}
+
+		_alpm_log(db->handle, PM_LOG_DEBUG, "checking signature for %s\n",
+				db->treename);
+		ret = _alpm_gpgme_checksig(db->handle, dbpath, NULL);
+		if((check_sig == PM_PGP_VERIFY_ALWAYS && ret != 0) ||
+				(check_sig == PM_PGP_VERIFY_OPTIONAL && ret == 1)) {
+			RET_ERR(db->handle, PM_ERR_SIG_INVALID, -1);
+		}
+	}
+
+	return 0;
+}
+
 /** Update a package database
  *
  * An update of the package database \a db will be attempted. Unless
@@ -144,6 +177,15 @@ int SYMEXPORT alpm_db_update(int force, pmdb_t *db)
 
 		if(ret == 0 && (check_sig == PM_PGP_VERIFY_ALWAYS ||
 					check_sig == PM_PGP_VERIFY_OPTIONAL)) {
+			/* an existing sig file is no good at this point */
+			char *sigpath = _alpm_db_sig_path(db);
+			if(!sigpath) {
+				ret = -1;
+				break;
+			}
+			unlink(sigpath);
+			free(sigpath);
+
 			int errors_ok = (check_sig == PM_PGP_VERIFY_OPTIONAL);
 			/* if we downloaded a DB, we want the .sig from the same server */
 			snprintf(fileurl, len, "%s/%s.db.sig", server, db->treename);
@@ -173,6 +215,11 @@ int SYMEXPORT alpm_db_update(int force, pmdb_t *db)
 	/* Cache needs to be rebuilt */
 	_alpm_db_free_pkgcache(db);
 
+	if(sync_db_validate(db)) {
+		/* pm_errno should be set */
+		ret = -1;
+	}
+
 cleanup:
 
 	free(syncpath);
@@ -523,7 +570,8 @@ struct db_operations sync_db_ops = {
 	.version          = sync_db_version,
 };
 
-pmdb_t *_alpm_db_register_sync(pmhandle_t *handle, const char *treename)
+pmdb_t *_alpm_db_register_sync(pmhandle_t *handle, const char *treename,
+		pgp_verify_t level)
 {
 	pmdb_t *db;
 
@@ -535,6 +583,12 @@ pmdb_t *_alpm_db_register_sync(pmhandle_t *handle, const char *treename)
 	}
 	db->ops = &sync_db_ops;
 	db->handle = handle;
+	db->pgp_verify = level;
+
+	if(sync_db_validate(db)) {
+		_alpm_db_free(db);
+		return NULL;
+	}
 
 	handle->dbs_sync = alpm_list_add(handle->dbs_sync, db);
 	return db;
diff --git a/lib/libalpm/db.c b/lib/libalpm/db.c
index c3a7abd2..2b50c064 100644
--- a/lib/libalpm/db.c
+++ b/lib/libalpm/db.c
@@ -45,7 +45,8 @@
  */
 
 /** Register a sync database of packages. */
-pmdb_t SYMEXPORT *alpm_db_register_sync(pmhandle_t *handle, const char *treename)
+pmdb_t SYMEXPORT *alpm_db_register_sync(pmhandle_t *handle, const char *treename,
+		pgp_verify_t check_sig)
 {
 	/* Sanity checks */
 	CHECK_HANDLE(handle, return NULL);
@@ -54,7 +55,7 @@ pmdb_t SYMEXPORT *alpm_db_register_sync(pmhandle_t *handle, const char *treename
 	/* Do not register a database if a transaction is on-going */
 	ASSERT(handle->trans == NULL, RET_ERR(handle, PM_ERR_TRANS_NOT_NULL, NULL));
 
-	return _alpm_db_register_sync(handle, treename);
+	return _alpm_db_register_sync(handle, treename, check_sig);
 }
 
 /* Helper function for alpm_db_unregister{_all} */
diff --git a/lib/libalpm/db.h b/lib/libalpm/db.h
index e3faeeb4..c5fcd5f0 100644
--- a/lib/libalpm/db.h
+++ b/lib/libalpm/db.h
@@ -77,7 +77,8 @@ int _alpm_db_version(pmdb_t *db);
 int _alpm_db_cmp(const void *d1, const void *d2);
 alpm_list_t *_alpm_db_search(pmdb_t *db, const alpm_list_t *needles);
 pmdb_t *_alpm_db_register_local(pmhandle_t *handle);
-pmdb_t *_alpm_db_register_sync(pmhandle_t *handle, const char *treename);
+pmdb_t *_alpm_db_register_sync(pmhandle_t *handle, const char *treename,
+		pgp_verify_t level);
 void _alpm_db_unregister(pmdb_t *db);
 
 /* be_*.c, backend specific calls */