pEpEngine/src/pEpEngine.c

// This file is under GNU General Public License 3.0
// see LICENSE.txt

#include "pEp_internal.h"
#include "dynamic_api.h"
#include "cryptotech.h"
#include "transport.h"
#include "blacklist.h"
#include "KeySync_fsm.h"

#include <time.h>
#include <stdlib.h>

#define _PEP_SQLITE_DEBUG 0
#if _PEP_SQLITE_DEBUG
#include <sqlite3.h>
#endif

static volatile int init_count = -1;

// sql overloaded functions - modified from sqlite3.c
static void _sql_lower(sqlite3_context* ctx, int argc, sqlite3_value** argv) {
    const char *z2;
    int n;
    z2 = (char*)sqlite3_value_text(argv[0]);
    n = sqlite3_value_bytes(argv[0]);
    /* Verify that the call to _bytes() does not invalidate the _text() pointer */
    assert( z2==(char*)sqlite3_value_text(argv[0]) );
    if( z2 ){
        char *z1 = (char*)sqlite3_malloc(n+1);
        if( z1 ){
            for(int i=0; i<n; i++){
                char c = z2[i];
                char c_mod = c | 0x20;
                if (c_mod < 0x61 || c_mod > 0x7a)
                    c_mod = c;
                z1[i] = c_mod;
            }
            z1[n] = '\0';
            sqlite3_result_text(ctx, z1, n, sqlite3_free);
        }
    }
}

#if _PEP_SQLITE_DEBUG
int sql_trace_callback (unsigned trace_constant, 
                        void* context_ptr,
                        void* P,
                        void* X) {
    switch (trace_constant) {
        case SQLITE_TRACE_STMT:
            fprintf(stderr, "SQL_DEBUG: STMT - ");
            const char* X_str = (const char*) X;
            if (!EMPTYSTR(X_str) && X_str[0] == '-' && X_str[1] == '-')
                fprintf(stderr, "%s\n", X_str);
            else
                fprintf(stderr, "%s\n", sqlite3_expanded_sql((sqlite3_stmt*)P));
            break;
        case SQLITE_TRACE_ROW:
            fprintf(stderr, "SQL_DEBUG: ROW - ");
            fprintf(stderr, "%s\n", sqlite3_expanded_sql((sqlite3_stmt*)P));
            break;            
        case SQLITE_TRACE_CLOSE:
            fprintf(stderr, "SQL_DEBUG: CLOSE - ");
            break;
        default:
            break;
    }
    return 0;
}
#endif

// sql manipulation statements
static const char *sql_log = 
    "insert into log (title, entity, description, comment)"
     "values (?1, ?2, ?3, ?4);";

static const char *sql_trustword = 
    "select id, word from wordlist where lang = lower(?1) "
    "and id = ?2 ;";

static const char *sql_get_identity =  
    "select fpr, username, comm_type, lang,"
    "   identity.flags | pgp_keypair.flags,"
    "   is_own"
    "   from identity"
    "   join person on id = identity.user_id"
    "   join pgp_keypair on fpr = identity.main_key_id"
    "   join trust on id = trust.user_id"
    "       and pgp_keypair_fpr = identity.main_key_id"    
    "   where (case when (address = ?1) then (1)"
    "               when (lower(address) = lower(?1)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?1),'.','')) then (1)"
    "               else 0"
    "          end) = 1"
    "   and identity.user_id = ?2" 
    "   order by is_own desc, "
    "   timestamp desc; ";

static const char *sql_get_identities_by_main_key_id =  
    "select address, identity.user_id, username, comm_type, lang,"
    "   identity.flags | pgp_keypair.flags,"
    "   is_own"
    "   from identity"
    "   join person on id = identity.user_id"
    "   join pgp_keypair on fpr = identity.main_key_id"
    "   join trust on id = trust.user_id"
    "       and pgp_keypair_fpr = identity.main_key_id"    
    "   where identity.main_key_id = ?1" 
    "   order by is_own desc, "
    "   timestamp desc; ";

static const char *sql_get_identity_without_trust_check =  
    "select identity.main_key_id, username, lang,"
    "   identity.flags, is_own"
    "   from identity"
    "   join person on id = identity.user_id"
    "   where (case when (address = ?1) then (1)"
    "               when (lower(address) = lower(?1)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?1),'.','')) then (1)"
    "               else 0"
    "          end) = 1"
    "   and identity.user_id = ?2 "
    "   order by is_own desc, "
    "   timestamp desc; ";

static const char *sql_get_identities_by_address =  
    "select user_id, identity.main_key_id, username, lang,"
    "   identity.flags, is_own"
    "   from identity"
    "   join person on id = identity.user_id"
    "   where (case when (address = ?1) then (1)"
    "               when (lower(address) = lower(?1)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?1),'.','')) then (1)"
    "               else 0"
    "          end) = 1 "
    "   order by is_own desc, "
    "   timestamp desc; ";
    
static const char *sql_get_identities_by_userid =  
    "select address, fpr, username, comm_type, lang,"
    "   identity.flags | pgp_keypair.flags,"
    "   is_own"
    "   from identity"
    "   join person on id = identity.user_id"
    "   join pgp_keypair on fpr = identity.main_key_id"
    "   join trust on id = trust.user_id"
    "       and pgp_keypair_fpr = identity.main_key_id"    
    "   where identity.user_id = ?1" 
    "   order by is_own desc, "
    "   timestamp desc; ";

static const char *sql_replace_identities_fpr =  
    "update identity"
    "   set main_key_id = ?1 "
    "   where main_key_id = ?2 ;";
    
static const char *sql_remove_fpr_as_default =
    "update person set main_key_id = NULL where main_key_id = ?1 ;"
    "update identity set main_key_id = NULL where main_key_id = ?1 ;";

// Set person, but if already exist, only update.
// if main_key_id already set, don't touch.
static const char *sql_set_person = 
     "insert into person (id, username, lang, main_key_id, device_group)"
     "  values (?1, ?2, ?3, ?4, "
     "          (select device_group from person where id = ?1)) ;";

static const char *sql_update_person = 
    "update person "
    "   set username = ?2, "
    "       lang = ?3, "
    "       main_key_id =  "
    "           (select coalesce( "
    "               (select main_key_id from person where id = ?1), " 
    "                upper(replace(?4,' ','')))),"         
    "       device_group = "
    "           (select device_group from person where id = ?1)"
    "   where id = ?1 ;";

// Will cascade.
static const char *sql_delete_person = 
     "delete from person where id = ?1 ;";

static const char *sql_set_as_pEp_user =
    "update person set is_pEp_user = 1 "
    "   where id = ?1 ; ";

static const char *sql_is_pEp_user =
    "select is_pEp_user from person "
    "   where id = ?1 ; ";

static const char* sql_exists_person = 
    "select count(*) from person "
    "   where id = ?1 ;";

static const char *sql_set_device_group = 
    "update person set device_group = ?1 "
    "   where id = ?2;";

// This will cascade to identity and trust
static const char* sql_replace_userid =
    "update person set id = ?1 " 
    "   where id = ?2;";

// Hopefully this cascades and removes trust entries...
static const char *sql_delete_key =
    "delete from pgp_keypair "
    "   where fpr = ?1 ; ";

static const char *sql_replace_main_user_fpr =  
    "update person "
    "   set main_key_id = ?1 "
    "   where id = ?2 ;";

static const char *sql_get_main_user_fpr =  
    "select main_key_id from person"
    "   where id = ?1 ;";

static const char *sql_refresh_userid_default_key =
    "update person "
    "   set main_key_id = "
    "       (select identity.main_key_id from identity "
    "           join trust on trust.user_id = identity.user_id "
    "               and trust.pgp_keypair_fpr = identity.main_key_id "
    "           join person on identity.user_id = identity.user_id "
    "       where identity.user_id = ?1 "
    "       order by trust.comm_type desc "
    "       limit 1) "
    "where id = ?1 ; ";

static const char *sql_get_device_group = 
    "select device_group from person "
    "where id = ?1;";

static const char *sql_set_pgp_keypair = 
    "insert or ignore into pgp_keypair (fpr) "
    "values (upper(replace(?1,' ',''))) ;";

static const char* sql_exists_identity_entry = 
    "select count(*) from identity "
    "   where (case when (address = ?1) then (1)"
    "               when (lower(address) = lower(?1)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?1),'.','')) then (1)"
    "               else 0"
    "          end) = 1"
    "    and user_id = ?2;";
 
static const char *sql_set_identity_entry = 
    "insert into identity ("
    "       address, main_key_id, "
    "       user_id, flags, is_own"
    "   ) values ("
    "       ?1,"
    "       upper(replace(?2,' ','')),"
    "       ?3,"
    "       ?4,"
    "       ?5"
    "   );";
    
static const char* sql_update_identity_entry =    
    "update identity "
    "   set main_key_id = upper(replace(?2,' ','')), "
    "       flags = ?4, " 
    "       is_own = ?5 "
    "   where (case when (address = ?1) then (1)"
    "               when (lower(address) = lower(?1)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?1),'.','')) then (1) "
    "               else 0 "
    "          end) = 1 "
    "          and user_id = ?3 ;";

    // " (select"
    // "   coalesce("
    // "    (select flags from identity"
    // "     where address = ?1 and"
    // "           user_id = ?3),"
    // "    0)"
    // " ) | (?4 & 255)"
    /* set_identity ignores previous flags, and doesn't filter machine flags */
        
static const char *sql_set_identity_flags = 
    "update identity set flags = "
    "    ((?1 & 255) | (select flags from identity"
    "                    where (case when (address = ?2) then (1)"
    "                                when (lower(address) = lower(?2)) then (1)"
    "                                when (replace(lower(address),'.','') = replace(lower(?2),'.','')) then (1)"
    "                                else 0 "    
    "                           end) = 1 "
    "                           and user_id = ?3)) "
    "   where (case when (address = ?2) then (1)"
    "               when (lower(address) = lower(?2)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?2),'.','')) then (1)"
    "               else 0"
    "          end) = 1"
    "          and user_id = ?3 ;";

static const char *sql_unset_identity_flags = 
    "update identity set flags = "
    "    ( ~(?1 & 255) & (select flags from identity"
    "                    where (case when (address = ?2) then (1)"
    "                                when (lower(address) = lower(?2)) then (1)"
    "                                when (replace(lower(address),'.','') = replace(lower(?2),'.','')) then (1)"
    "                                else 0 "    
    "                           end) = 1 "
    "                           and user_id = ?3)) "
    "   where (case when (address = ?2) then (1)"
    "               when (lower(address) = lower(?2)) then (1)"
    "               when (replace(lower(address),'.','') = replace(lower(?2),'.','')) then (1)"
    "               else 0"
    "          end) = 1"
    "          and user_id = ?3 ;";

static const char *sql_set_trust =
    "insert into trust (user_id, pgp_keypair_fpr, comm_type) "
    "values (?1, upper(replace(?2,' ','')), ?3) ;";

static const char *sql_update_trust =
    "update trust set comm_type = ?3 " 
    "   where user_id = ?1 and pgp_keypair_fpr = upper(replace(?2,' ',''));";

static const char *sql_update_trust_to_pEp =
    "update trust set comm_type = comm_type + 71 "
    "   where (user_id = ?1 "
    "          and (case when (comm_type = 56) then (1) "
    "                    when (comm_type = 184) then (1) "
    "                    else 0"
    "               end) = 1); ";

static const char* sql_exists_trust_entry = 
    "select count(*) from trust "
    "   where user_id = ?1 and pgp_keypair_fpr = upper(replace(?2,' ',''));";
    
static const char *sql_update_trust_for_fpr =
    "update trust "
    "set comm_type = ?1 "
    "where pgp_keypair_fpr = upper(replace(?2,' ','')) ;";

static const char *sql_get_trust = 
    "select comm_type from trust where user_id = ?1 "
    "and pgp_keypair_fpr = upper(replace(?2,' ','')) ;";

static const char *sql_get_trust_by_userid = 
    "select pgp_keypair_fpr, comm_type from trust where user_id = ?1 ";

static const char *sql_least_trust = 
    "select min(comm_type) from trust where"
    " pgp_keypair_fpr = upper(replace(?1,' ',''))"
    " and comm_type != 0;"; // ignores PEP_ct_unknown
    // returns PEP_ct_unknown only when no known trust is recorded

static const char *sql_mark_as_compromised = 
    "update trust not indexed set comm_type = 15"
    " where pgp_keypair_fpr = upper(replace(?1,' ','')) ;";
    
static const char *sql_crashdump = 
    "select timestamp, title, entity, description, comment"
    " from log order by timestamp desc limit ?1 ;";

static const char *sql_languagelist = 
    "select i18n_language.lang, name, phrase" 
    " from i18n_language join i18n_token using (lang) where i18n_token.id = 1000;" ;

static const char *sql_i18n_token = 
    "select phrase from i18n_token where lang = lower(?1) and id = ?2 ;";

// blacklist
static const char *sql_blacklist_add = 
    "insert or ignore into blacklist_keys (fpr) values (upper(replace(?1,' ',''))) ;"
    "delete from identity where main_key_id = upper(replace(?1,' ','')) ;"
    "delete from pgp_keypair where fpr = upper(replace(?1,' ','')) ;";

static const char *sql_blacklist_delete =
    "delete from blacklist_keys where fpr = upper(replace(?1,' ','')) ;";

static const char *sql_blacklist_is_listed = 
    "select count(*) from blacklist_keys where fpr = upper(replace(?1,' ','')) ;";

static const char *sql_blacklist_retrieve = 
    "select * from blacklist_keys ;";
                

// Own keys
// We only care if it's 0 or non-zero
static const char *sql_own_key_is_listed = 
    "select count(*) from ("
    "   select pgp_keypair_fpr from trust"
    "      join identity on trust.user_id = identity.user_id"
    "      where pgp_keypair_fpr = upper(replace(?1,' ',''))"
    "           and identity.is_own = 1"
    ");";

static const char *sql_own_identities_retrieve =  
    "select address, fpr, identity.user_id, username,"
    "   lang, identity.flags | pgp_keypair.flags"
    "   from identity"
    "   join person on id = identity.user_id"
    "   join pgp_keypair on fpr = identity.main_key_id"
    "   join trust on id = trust.user_id"
    "       and pgp_keypair_fpr = identity.main_key_id"
    "   where identity.is_own = 1"
    "       and (identity.flags & ?1) = 0;";

static const char *sql_own_keys_retrieve = 
    "select pgp_keypair_fpr from trust"
    "   join identity on trust.user_id = identity.user_id"
    "   where identity.is_own = 1";

static const char* sql_get_user_default_key =
    "select main_key_id from person" 
    "   where id = ?1;";

static const char* sql_get_all_keys_for_user =
    "select pgp_keypair_fpr from trust"
    "   where user_id = ?1; ";

static const char* sql_get_default_own_userid =
    "select id from person"
    "   join identity on id = identity.user_id"
    "   where identity.is_own = 1";

// Sequence
static const char *sql_sequence_value1 = 
    "insert or replace into sequences (name, value) "
    "values (?1, "
    "       (select coalesce((select value + 1 from sequences "
    "           where name = ?1), 1 ))); ";

static const char *sql_sequence_value2 = 
    "select value from sequences where name = ?1 ;";

// Revocation tracking
static const char *sql_set_revoked =
    "insert or replace into revoked_keys ("
    "    revoked_fpr, replacement_fpr, revocation_date) "
    "values (upper(replace(?1,' ','')),"
    "        upper(replace(?2,' ','')),"
    "        ?3) ;";
        
static const char *sql_get_revoked = 
    "select revoked_fpr, revocation_date from revoked_keys"
    "    where replacement_fpr = upper(replace(?1,' ','')) ;";

static const char *sql_get_replacement_fpr = 
    "select replacement_fpr, revocation_date from revoked_keys"
    "    where revoked_fpr = upper(replace(?1,' ','')) ;";

static const char *sql_get_userid_alias_default =
    "select default_id from alternate_user_id "
    "   where alternate_id = ?1 ; ";

// Revocation tracking
static const char *sql_add_mistrusted_key =
    "insert or replace into mistrusted_keys (fpr) "
    "   values (upper(replace(?1,' ',''))) ;";
        
static const char *sql_delete_mistrusted_key = 
    "delete from mistrusted_keys where fpr = upper(replace(?1,' ','')) ;";

static const char *sql_is_mistrusted_key = 
    "select count(*) from mistrusted_keys where fpr = upper(replace(?1,' ','')) ;";

static const char *sql_add_userid_alias =
    "insert or replace into alternate_user_id (alternate_id, default_id) "
    "values (?2, ?1) ;";

static const char *sql_add_into_social_graph =
    "insert or replace into social_graph(own_userid, own_address, contact_userid) "
    "values (?1, ?2, ?3) ;";

static const char *sql_get_own_address_binding_from_contact =
    "select own_address from social_graph where own_userid = ?1 and contact_userid = ?2 ;";

static const char *sql_set_revoke_contact_as_notified =
    "insert or replace into revocation_contact_list(fpr, contact_id) values (?1, ?2) ;";
    
static const char *sql_get_contacted_ids_from_revoke_fpr =
    "select * from revocation_contact_list where fpr = ?1 ;";

static const char *sql_was_id_for_revoke_contacted = 
    "select count(*) from revocation_contact_list where fpr = ?1 and contact_id = ?2 ;";

// We only need user_id and address, since in the main usage, we'll call update_identity
// on this anyway when sending out messages.
static const char *sql_get_last_contacted =
    "select user_id, address from identity where datetime('now') < datetime(timestamp, '+14 days') ; ";
    
static int user_version(void *_version, int count, char **text, char **name)
{
    assert(_version);
    assert(count == 1);
    assert(text && text[0]);
    if (!(_version && count == 1 && text && text[0]))
        return -1;

    int *version = (int *) _version;
    *version = atoi(text[0]);
    return 0;
}

static int table_contains_column(PEP_SESSION session, const char* table_name,
                                                      const char* col_name) {


    if (!session || !table_name || !col_name)
        return -1;
        
    // Table names can't be SQL parameters, so we do it this way.
    
    // these two must be the same number.
    char sql_buf[500];
    const size_t max_q_len = 500;
    
    size_t t_size, c_size, q_size;
    
    const char* q1 = "SELECT "; // 7
    const char* q2 = " from "; // 6
    const char* q3 = ";";       // 1
    
    q_size = 14;
    t_size = strlen(table_name);
    c_size = strlen(col_name);
    
    size_t query_len = q_size + c_size + t_size + 1;
    
    if (query_len > max_q_len)
        return -1;

    strlcpy(sql_buf, q1, max_q_len);
    strlcat(sql_buf, col_name, max_q_len);
    strlcat(sql_buf, q2, max_q_len);
    strlcat(sql_buf, table_name, max_q_len);
    strlcat(sql_buf, q3, max_q_len);

    sqlite3_stmt *stmt; 

    sqlite3_prepare_v2(session->db, sql_buf, -1, &stmt, NULL);

    int retval = 0;

    int rc = sqlite3_step(stmt);  
    if (rc == SQLITE_DONE || rc == SQLITE_OK || rc == SQLITE_ROW) {
        retval = 1;
    }

    sqlite3_finalize(stmt);      
        
    return retval;
}

void errorLogCallback(void *pArg, int iErrCode, const char *zMsg){
  fprintf(stderr, "(%d) %s\n", iErrCode, zMsg);
}

#ifdef USE_GPG
PEP_STATUS pgp_import_ultimately_trusted_keypairs(PEP_SESSION session);
#endif // USE_GPG

DYNAMIC_API PEP_STATUS init(
        PEP_SESSION *session,
        messageToSend_t messageToSend,
        inject_sync_event_t inject_sync_event
    )
{
    PEP_STATUS status = PEP_STATUS_OK;
    int int_result;
    
    bool in_first = false;
    bool very_first = false;

    assert(sqlite3_threadsafe());
    if (!sqlite3_threadsafe())
        return PEP_INIT_SQLITE3_WITHOUT_MUTEX;

    // a little race condition - but still a race condition
    // mitigated by calling caveat (see documentation)

    // this increment is made atomic IN THE ADAPTERS by
    // guarding the call to init with the appropriate mutex.
    int _count = ++init_count;
    if (_count == 0)
        in_first = true;
    
    // Race condition mitigated by calling caveat starts here :
    // If another call to init() preempts right now, then preemptive call
    // will have in_first false, will not create SQL tables, and following
    // calls relying on those tables will fail.
    //
    // Therefore, as above, adapters MUST guard init() with a mutex.
    // 
    // Therefore, first session
    // is to be created and last session to be deleted alone, and not
    // concurently to other sessions creation or deletion.
    // We expect adapters to enforce this either by implicitely creating a
    // client session, or by using synchronization primitive to protect
    // creation/deletion of first/last session from the app.

    assert(session);
    if (session == NULL)
        return PEP_ILLEGAL_VALUE;

    *session = NULL;

    pEpSession *_session = calloc(1, sizeof(pEpSession));
    assert(_session);
    if (_session == NULL)
        goto enomem;

    _session->version = PEP_ENGINE_VERSION;
    _session->messageToSend = messageToSend;
    _session->inject_sync_event = inject_sync_event;

#ifdef DEBUG_ERRORSTACK
    _session->errorstack = new_stringlist("init()");
#endif

    assert(LOCAL_DB);
    if (LOCAL_DB == NULL) {
        status = PEP_INIT_CANNOT_OPEN_DB;
        goto pEp_error;
    }
    
#if _PEP_SQLITE_DEBUG    
    sqlite3_config(SQLITE_CONFIG_LOG, errorLogCallback, NULL);
#endif

    int_result = sqlite3_open_v2(
            LOCAL_DB,
            &_session->db,
            SQLITE_OPEN_READWRITE
                | SQLITE_OPEN_CREATE
                | SQLITE_OPEN_FULLMUTEX
                | SQLITE_OPEN_PRIVATECACHE,
            NULL 
        );

    if (int_result != SQLITE_OK) {
        status = PEP_INIT_CANNOT_OPEN_DB;
        goto pEp_error;
    }

    int_result = sqlite3_exec(
            _session->db,
            "PRAGMA locking_mode=NORMAL;\n"
            "PRAGMA journal_mode=WAL;\n",
            NULL,
            NULL,
            NULL
        );


    sqlite3_busy_timeout(_session->db, BUSY_WAIT_TIME);

#if _PEP_SQLITE_DEBUG
    sqlite3_trace_v2(_session->db, 
        SQLITE_TRACE_STMT | SQLITE_TRACE_ROW | SQLITE_TRACE_CLOSE,
        sql_trace_callback,
        NULL);
#endif

    assert(SYSTEM_DB);
    if (SYSTEM_DB == NULL) {
        status = PEP_INIT_CANNOT_OPEN_SYSTEM_DB;
        goto pEp_error;
    }

    int_result = sqlite3_open_v2(
            SYSTEM_DB, &_session->system_db,
            SQLITE_OPEN_READONLY
                | SQLITE_OPEN_FULLMUTEX
                | SQLITE_OPEN_SHAREDCACHE,
            NULL
        );

    if (int_result != SQLITE_OK) {
        status = PEP_INIT_CANNOT_OPEN_SYSTEM_DB;
        goto pEp_error;
    }

    sqlite3_busy_timeout(_session->system_db, 1000);

// increment this when patching DDL
#define _DDL_USER_VERSION "9"

    if (in_first) {

        int_result = sqlite3_exec(
            _session->db,
                "create table if not exists version_info (\n"
                "   id integer primary key,\n"
                "   timestamp integer default (datetime('now')),\n"
                "   version text,\n"
                "   comment text\n"
                ");\n",
                NULL,
                NULL,
                NULL
        );
        int_result = sqlite3_exec(
            _session->db,
                "PRAGMA application_id = 0x23423423;\n"
                "create table if not exists log (\n"
                "   timestamp integer default (datetime('now')),\n"
                "   title text not null,\n"
                "   description text,\n"
                "   entity text not null,\n"
                "   comment text\n"
                ");\n"
                "create index if not exists log_timestamp on log (\n"
                "   timestamp\n"
                ");\n"
                "create table if not exists pgp_keypair (\n"
                "   fpr text primary key,\n"
                "   created integer,\n"
                "   expires integer,\n"
                "   comment text,\n"
                "   flags integer default 0\n"
                ");\n"
                "create index if not exists pgp_keypair_expires on pgp_keypair (\n"