src/lib-auth/auth-master.c

	auth-master.c revision bdd36cfdba3ff66d25570a9ff568d69e1eb543cf
/* Copyright (c) 2005-2012 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "lib-signals.h"
#include "array.h"
#include "ioloop.h"
#include "eacces-error.h"
#include "net.h"
#include "istream.h"
#include "ostream.h"
#include "str.h"
#include "strescape.h"
#include "master-interface.h"
#include "auth-master.h"

#include <stdlib.h>
#include <unistd.h>

#define AUTH_PROTOCOL_MAJOR 1
#define AUTH_PROTOCOL_MINOR 0

#define AUTH_MASTER_IDLE_SECS 60

#define MAX_INBUF_SIZE 8192
#define MAX_OUTBUF_SIZE 1024

#define DEFAULT_USERDB_LOOKUP_PREFIX "userdb lookup"

struct auth_master_connection {
    char *auth_socket_path;
    enum auth_master_flags flags;

    int fd;
    struct ioloop *ioloop;
    struct io *io;
    struct istream *input;
    struct ostream *output;
    struct timeout *to;
    const char *prefix;

    unsigned int request_counter;

    bool (*reply_callback)(const char *cmd, const char *const *args,
                   void *context);
    void *reply_context;

    unsigned int sent_handshake:1;
    unsigned int handshaked:1;
    unsigned int aborted:1;
};

struct auth_master_lookup_ctx {
    struct auth_master_connection *conn;
    const char *user;
    const char *expected_reply;
    int return_value;

    pool_t pool;
    const char **fields;
};

struct auth_master_user_list_ctx {
    struct auth_master_connection *conn;
    pool_t pool;
    ARRAY_TYPE(const_string) users;
    const char *const *user_strings;
    unsigned int idx, user_count;
    bool failed;
};

static void auth_input(struct auth_master_connection *conn);

struct auth_master_connection *
auth_master_init(const char *auth_socket_path, enum auth_master_flags flags)
{
    struct auth_master_connection *conn;

    conn = i_new(struct auth_master_connection, 1);
    conn->auth_socket_path = i_strdup(auth_socket_path);
    conn->fd = -1;
    conn->flags = flags;
    conn->prefix = DEFAULT_USERDB_LOOKUP_PREFIX;
    return conn;
}

static void auth_connection_close(struct auth_master_connection *conn)
{
    if (conn->to != NULL)
        timeout_remove(&conn->to);
    if (conn->fd != -1) {
        if (close(conn->fd) < 0)
            i_error("close(%s) failed: %m", conn->auth_socket_path);
        conn->fd = -1;
    }

    conn->sent_handshake = FALSE;
    conn->handshaked = FALSE;
}

void auth_master_deinit(struct auth_master_connection **_conn)
{
    struct auth_master_connection *conn = *_conn;

    *_conn = NULL;
    auth_connection_close(conn);
    i_free(conn->auth_socket_path);
    i_free(conn);
}

static void auth_request_lookup_abort(struct auth_master_connection *conn)
{
    io_loop_stop(conn->ioloop);
    conn->aborted = TRUE;
}

static int auth_input_handshake(struct auth_master_connection *conn)
{
    const char *line, *const *tmp;

    while ((line = i_stream_next_line(conn->input)) != NULL) {
        tmp = t_strsplit_tab(line);
        if (strcmp(tmp[0], "VERSION") == 0 &&
            tmp[1] != NULL && tmp[2] != NULL) {
            if (strcmp(tmp[1], dec2str(AUTH_PROTOCOL_MAJOR)) != 0) {
                i_error("userdb lookup: "
                    "Auth protocol version mismatch "
                    "(%s vs %d)", tmp[1],
                    AUTH_PROTOCOL_MAJOR);
                auth_request_lookup_abort(conn);
                return -1;
            }
        } else if (strcmp(tmp[0], "SPID") == 0) {
            conn->handshaked = TRUE;
            break;
        }
    }
    return 0;
}

static int parse_reply(const char *cmd, const char *const *args,
               const char *expected_reply, const char *user, bool debug)
{
    if (strcmp(cmd, expected_reply) == 0)
        return 1;
    if (strcmp(cmd, "NOTFOUND") == 0)
        return 0;
    if (strcmp(cmd, "FAIL") == 0) {
        if (*args == NULL) {
            i_error("user %s: Auth %s lookup failed",
                user, expected_reply);
        } else if (debug) {
            i_debug("user %s: Auth %s lookup returned temporary failure: %s",
                user, expected_reply, *args);
        }
        return -1;
    }
    i_error("Unknown reply: %s", cmd);
    return -1;
}

static const char *const *args_hide_passwords(const char *const *args)
{
    ARRAY_TYPE(const_string) new_args;
    const char *p, *p2;
    unsigned int i;

    /* if there are any keys that contain "pass" string */
    for (i = 0; args[i] != NULL; i++) {
        p = strstr(args[i], "pass");
        if (p != NULL && p < strchr(args[i], '='))
            break;
    }
    if (args[i] == NULL)
        return args;

    /* there are. replace their values with <hidden> */
    t_array_init(&new_args, i + 16);
    array_append(&new_args, args, i);
    for (; args[i] != NULL; i++) {
        p = strstr(args[i], "pass");
        p2 = strchr(args[i], '=');
        if (p != NULL && p < p2) {
            p = t_strconcat(t_strdup_until(args[i], p2),
                    "=<hidden>", NULL);
            array_append(&new_args, &p, 1);
        } else {
            array_append(&new_args, &args[i], 1);
        }
    }
    array_append_zero(&new_args);
    return array_idx(&new_args, 0);
}

static bool auth_lookup_reply_callback(const char *cmd, const char *const *args,
                       void *context)
{
    struct auth_master_lookup_ctx *ctx = context;
    unsigned int i, len;
    bool debug = (ctx->conn->flags & AUTH_MASTER_FLAG_DEBUG) != 0;

    io_loop_stop(ctx->conn->ioloop);

    ctx->return_value =
        parse_reply(cmd, args, ctx->expected_reply, ctx->user, debug);

    len = str_array_length(args);
    if (ctx->return_value >= 0) {
        ctx->fields = p_new(ctx->pool, const char *, len + 1);
        for (i = 0; i < len; i++)
            ctx->fields[i] = p_strdup(ctx->pool, args[i]);
    } else {
        /* put the reason string into first field */
        ctx->fields = p_new(ctx->pool, const char *, 2);
        for (i = 0; i < len; i++) {
            if (strncmp(args[i], "reason=", 7) == 0) {
                ctx->fields[0] =
                    p_strdup(ctx->pool, args[i] + 7);
                break;
            }
        }
    }
    if (debug) {
        args = args_hide_passwords(args);
        i_debug("auth input: %s", t_strarray_join(args, " "));
    }
    return TRUE;
}

static bool
auth_handle_line(struct auth_master_connection *conn, const char *line)
{
    const char *cmd, *const *args, *id, *wanted_id;

    args = t_strsplit_tab(line);
    cmd = *args; args++;
    if (*args == NULL)
        id = "";
    else {
        id = *args;
        args++;
    }

    wanted_id = dec2str(conn->request_counter);
    if (strcmp(id, wanted_id) == 0)
        return conn->reply_callback(cmd, args, conn->reply_context);

    if (strcmp(cmd, "CUID") == 0) {
        i_error("%s: %s is an auth client socket. "
            "It should be a master socket.",
            conn->prefix, conn->auth_socket_path);
    } else {
        i_error("%s: BUG: Unexpected input: %s", conn->prefix, line);
    }
    auth_request_lookup_abort(conn);
    return FALSE;
}

static void auth_input(struct auth_master_connection *conn)
{
    const char *line;
    bool ret;

    switch (i_stream_read(conn->input)) {
    case 0:
        return;
    case -1:
        /* disconnected */
        i_error("%s: Disconnected unexpectedly",
            conn->prefix);
        auth_request_lookup_abort(conn);
        return;
    case -2:
        /* buffer full */
        i_error("%s: BUG: Received more than %d bytes",
            conn->prefix, MAX_INBUF_SIZE);
        auth_request_lookup_abort(conn);
        return;
    }

    if (!conn->handshaked) {
        if (auth_input_handshake(conn) < 0)
            return;
    }

    while ((line = i_stream_next_line(conn->input)) != NULL) {
        T_BEGIN {
            ret = auth_handle_line(conn, line);
        } T_END;
        if (!ret)
            return;
    }
}

static int auth_master_connect(struct auth_master_connection *conn)
{
    int fd;

    i_assert(conn->fd == -1);

    /* max. 1 second wait here. */
    fd = net_connect_unix_with_retries(conn->auth_socket_path, 1000);
    if (fd == -1) {
        if (errno == EACCES) {
            i_error("userdb lookup: %s",
                eacces_error_get("connect",
                         conn->auth_socket_path));
        } else {
            i_error("userdb lookup: connect(%s) failed: %m",
                conn->auth_socket_path);
        }
        return -1;
    }
    conn->fd = fd;
    return 0;
}

static void auth_request_timeout(struct auth_master_connection *conn)
{
    if (!conn->handshaked)
        i_error("%s: Connecting timed out", conn->prefix);
    else
        i_error("%s: Request timed out", conn->prefix);
    auth_request_lookup_abort(conn);
}

static void auth_idle_timeout(struct auth_master_connection *conn)
{
    auth_connection_close(conn);
}

static void auth_master_set_io(struct auth_master_connection *conn)
{
    if (conn->to != NULL)
        timeout_remove(&conn->to);

    conn->ioloop = io_loop_create();
    conn->input = i_stream_create_fd(conn->fd, MAX_INBUF_SIZE, FALSE);
    conn->output = o_stream_create_fd(conn->fd, MAX_OUTBUF_SIZE, FALSE);
    conn->io = io_add(conn->fd, IO_READ, auth_input, conn);
    conn->to = timeout_add(1000*MASTER_AUTH_LOOKUP_TIMEOUT_SECS,
                   auth_request_timeout, conn);
    lib_signals_reset_ioloop();
}

static void auth_master_unset_io(struct auth_master_connection *conn,
                 struct ioloop *prev_ioloop)
{
    if (prev_ioloop != NULL) {
        io_loop_set_current(prev_ioloop);
        lib_signals_reset_ioloop();
    }
    io_loop_set_current(conn->ioloop);

    timeout_remove(&conn->to);
    io_remove(&conn->io);
    i_stream_unref(&conn->input);
    o_stream_unref(&conn->output);
    io_loop_destroy(&conn->ioloop);

    if ((conn->flags & AUTH_MASTER_FLAG_NO_IDLE_TIMEOUT) == 0) {
        if (prev_ioloop == NULL)
            auth_connection_close(conn);
        else {
            conn->to = timeout_add(1000*AUTH_MASTER_IDLE_SECS,
                           auth_idle_timeout, conn);
        }
    }
}

static bool is_valid_string(const char *str)
{
    const char *p;

    /* make sure we're not sending any characters that have a special
       meaning. */
    for (p = str; *p != '\0'; p++) {
        if (*p == '\t' || *p == '\n' || *p == '\r')
            return FALSE;
    }
    return TRUE;
}

static int auth_master_run_cmd(struct auth_master_connection *conn,
                   const char *cmd)
{
    struct ioloop *prev_ioloop;
    const char *str;

    if (conn->fd == -1) {
        if (auth_master_connect(conn) < 0)
            return -1;
    }

    prev_ioloop = current_ioloop;
    auth_master_set_io(conn);

    o_stream_cork(conn->output);
    if (!conn->sent_handshake) {
        str = t_strdup_printf("VERSION\t%d\t%d\n",
                      AUTH_PROTOCOL_MAJOR, AUTH_PROTOCOL_MINOR);
        o_stream_nsend_str(conn->output, str);
        conn->sent_handshake = TRUE;
    }

    o_stream_nsend_str(conn->output, cmd);
    o_stream_uncork(conn->output);

    if (o_stream_nfinish(conn->output) < 0) {
        i_error("write(auth socket) failed: %m");
        conn->aborted = TRUE;
    } else {
        io_loop_run(conn->ioloop);
    }

    auth_master_unset_io(conn, prev_ioloop);
    if (conn->aborted) {
        conn->aborted = FALSE;
        auth_connection_close(conn);
        return -1;
    }
    return 0;
}

static unsigned int
auth_master_next_request_id(struct auth_master_connection *conn)
{
    if (++conn->request_counter == 0) {
        /* avoid zero */
        conn->request_counter++;
    }
    return conn->request_counter;
}

static void
auth_user_info_export(string_t *str, const struct auth_user_info *info)
{
    if (info->service != NULL) {
        str_append(str, "\tservice=");
        str_append(str, info->service);
    }

    if (info->local_ip.family != 0)
        str_printfa(str, "\tlip=%s", net_ip2addr(&info->local_ip));
    if (info->local_port != 0)
        str_printfa(str, "\tlport=%d", info->local_port);
    if (info->remote_ip.family != 0)
        str_printfa(str, "\trip=%s", net_ip2addr(&info->remote_ip));
    if (info->remote_port != 0)
        str_printfa(str, "\trport=%d", info->remote_port);
}

int auth_master_user_lookup(struct auth_master_connection *conn,
                const char *user, const struct auth_user_info *info,
                pool_t pool, const char **username_r,
                const char *const **fields_r)
{
    struct auth_master_lookup_ctx ctx;
    string_t *str;

    if (!is_valid_string(user) || !is_valid_string(info->service)) {
        /* non-allowed characters, the user can't exist */
        *username_r = NULL;
        *fields_r = NULL;
        return 0;
    }

    memset(&ctx, 0, sizeof(ctx));
    ctx.conn = conn;
    ctx.return_value = -1;
    ctx.pool = pool;
    ctx.expected_reply = "USER";
    ctx.user = user;

    conn->reply_callback = auth_lookup_reply_callback;
    conn->reply_context = &ctx;

    str = t_str_new(128);
    str_printfa(str, "USER\t%u\t%s",
            auth_master_next_request_id(conn), user);
    auth_user_info_export(str, info);
    str_append_c(str, '\n');

    conn->prefix = t_strdup_printf("userdb lookup(%s)", user);
    (void)auth_master_run_cmd(conn, str_c(str));
    conn->prefix = DEFAULT_USERDB_LOOKUP_PREFIX;

    if (ctx.return_value <= 0 || ctx.fields[0] == NULL) {
        *username_r = NULL;
        *fields_r = ctx.fields != NULL ? ctx.fields :
            p_new(pool, const char *, 1);
        if (ctx.return_value > 0) {
            i_error("Userdb lookup didn't return username");
            ctx.return_value = -1;
        }
    } else {
        *username_r = ctx.fields[0];
        *fields_r = ctx.fields + 1;
    }
    return ctx.return_value;
}

void auth_user_fields_parse(const char *const *fields, pool_t pool,
                struct auth_user_reply *reply_r)
{
    memset(reply_r, 0, sizeof(*reply_r));
    reply_r->uid = (uid_t)-1;
    reply_r->gid = (gid_t)-1;
    p_array_init(&reply_r->extra_fields, pool, 64);

    for (; *fields != NULL; fields++) {
        if (strncmp(*fields, "uid=", 4) == 0) {
            if (str_to_uid(*fields + 4, &reply_r->uid) < 0)
                i_error("Invalid uid in reply");
        } else if (strncmp(*fields, "gid=", 4) == 0) {
            if (str_to_gid(*fields + 4, &reply_r->gid) < 0)
                i_error("Invalid gid in reply");
        } else if (strncmp(*fields, "home=", 5) == 0)
            reply_r->home = p_strdup(pool, *fields + 5);
        else if (strncmp(*fields, "chroot=", 7) == 0)
            reply_r->chroot = p_strdup(pool, *fields + 7);
        else if (strcmp(*fields, "anonymous") == 0)
            reply_r->anonymous = TRUE;
        else {
            const char *field = p_strdup(pool, *fields);
            array_append(&reply_r->extra_fields, &field, 1);
        }
    }
}

int auth_master_pass_lookup(struct auth_master_connection *conn,
                const char *user, const struct auth_user_info *info,
                pool_t pool, const char *const **fields_r)
{
    struct auth_master_lookup_ctx ctx;
    string_t *str;

    if (!is_valid_string(user) || !is_valid_string(info->service)) {
        /* non-allowed characters, the user can't exist */
        *fields_r = NULL;
        return 0;
    }

    memset(&ctx, 0, sizeof(ctx));
    ctx.conn = conn;
    ctx.return_value = -1;
    ctx.pool = pool;
    ctx.expected_reply = "PASS";
    ctx.user = user;

    conn->reply_callback = auth_lookup_reply_callback;
    conn->reply_context = &ctx;

    str = t_str_new(128);
    str_printfa(str, "PASS\t%u\t%s",
            auth_master_next_request_id(conn), user);
    auth_user_info_export(str, info);
    str_append_c(str, '\n');

    conn->prefix = t_strdup_printf("passdb lookup(%s)", user);
    (void)auth_master_run_cmd(conn, str_c(str));
    conn->prefix = DEFAULT_USERDB_LOOKUP_PREFIX;

    *fields_r = ctx.fields != NULL ? ctx.fields :
        p_new(pool, const char *, 1);
    return ctx.return_value;
}

static bool
auth_cache_flush_reply_callback(const char *cmd, const char *const *args,
                void *context)
{
    unsigned int *countp = context;

    if (strcmp(cmd, "OK") != 0)
        *countp = -1U;
    else if (args[0] == NULL || str_to_uint(args[0], countp) < 0)
        *countp = -1U;

    io_loop_stop(current_ioloop);
    return TRUE;
}

int auth_master_cache_flush(struct auth_master_connection *conn,
                const char *const *users, unsigned int *count_r)
{
    string_t *str;

    *count_r = -1U;

    conn->reply_callback = auth_cache_flush_reply_callback;
    conn->reply_context = count_r;

    str = t_str_new(128);
    str_printfa(str, "CACHE-FLUSH\t%u", auth_master_next_request_id(conn));
    if (users != NULL) {
        for (; *users != NULL; users++) {
            str_append_c(str, '\t');
            str_append_tabescaped(str, *users);
        }
    }
    str_append_c(str, '\n');

    conn->prefix = "auth cache flush";
    (void)auth_master_run_cmd(conn, str_c(str));
    conn->prefix = DEFAULT_USERDB_LOOKUP_PREFIX;

    return *count_r == -1U ? -1 : 0;
}

static bool
auth_user_list_reply_callback(const char *cmd, const char *const *args,
                  void *context)
{
    struct auth_master_user_list_ctx *ctx = context;
    const char *user;

    timeout_reset(ctx->conn->to);

    if (strcmp(cmd, "DONE") == 0) {
        io_loop_stop(ctx->conn->ioloop);
        if (args[0] != NULL && strcmp(args[0], "fail") == 0) {
            i_error("User listing returned failure");
            ctx->failed = TRUE;
        }
        return TRUE;
    }
    if (strcmp(cmd, "LIST") == 0 && args[0] != NULL) {
        /* we'll just read all the users into memory. otherwise we'd
           have to use a separate connection for listing and there's
           a higher chance of a failure since the connection could be
           open to dovecot-auth for a long time. */
        user = p_strdup(ctx->pool, args[0]);
        array_append(&ctx->users, &user, 1);
        return TRUE;
    }
    return FALSE;
}

struct auth_master_user_list_ctx *
auth_master_user_list_init(struct auth_master_connection *conn,
               const char *user_mask,
               const struct auth_user_info *info)
{
    struct auth_master_user_list_ctx *ctx;
    string_t *str;
    pool_t pool;

    pool = pool_alloconly_create("auth master user list", 10240);
    ctx = p_new(pool, struct auth_master_user_list_ctx, 1);
    ctx->pool = pool;
    ctx->conn = conn;
    i_array_init(&ctx->users, 128);

    conn->reply_callback = auth_user_list_reply_callback;
    conn->reply_context = ctx;

    str = t_str_new(128);
    str_printfa(str, "LIST\t%u",
            auth_master_next_request_id(conn));
    if (*user_mask != '\0')
        str_printfa(str, "\tuser=%s", user_mask);
    if (info != NULL)
        auth_user_info_export(str, info);
    str_append_c(str, '\n');

    conn->prefix = "userdb list";
    if (auth_master_run_cmd(conn, str_c(str)) < 0)
        ctx->failed = TRUE;
    ctx->user_strings = array_get(&ctx->users, &ctx->user_count);
    conn->prefix = DEFAULT_USERDB_LOOKUP_PREFIX;
    return ctx;
}

const char *auth_master_user_list_next(struct auth_master_user_list_ctx *ctx)
{
    if (ctx->idx == ctx->user_count)
        return NULL;
    return ctx->user_strings[ctx->idx++];
}

unsigned int auth_master_user_list_count(struct auth_master_user_list_ctx *ctx)
{
    return ctx->user_count;
}

int auth_master_user_list_deinit(struct auth_master_user_list_ctx **_ctx)
{
    struct auth_master_user_list_ctx *ctx = *_ctx;
    int ret = ctx->failed ? -1 : 0;

    *_ctx = NULL;
    array_free(&ctx->users);
    pool_unref(&ctx->pool);
    return ret;
}