eng_ctrl.c

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/* crypto/engine/eng_ctrl.c */
/* ====================================================================
 * Copyright (c) 1999-2001 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    distribution.
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 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
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 * 5. Products derived from this software may not be called "OpenSSL"
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 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
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 *
 * This product includes cryptographic software written by Eric Young
 * ([email protected]).  This product includes software written by Tim
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 */

#include "eng_int.h"

/* When querying a ENGINE-specific control command's 'description', this string
 * is used if the ENGINE_CMD_DEFN has cmd_desc set to NULL. */
static const char *int_no_description = "";

/* These internal functions handle 'CMD'-related control commands when the
 * ENGINE in question has asked us to take care of it (ie. the ENGINE did not
 * set the ENGINE_FLAGS_MANUAL_CMD_CTRL flag. */

static int int_ctrl_cmd_is_null(const ENGINE_CMD_DEFN *defn)
    {
    if((defn->cmd_num == 0) || (defn->cmd_name == NULL))
        return 1;
    return 0;
    }

static int int_ctrl_cmd_by_name(const ENGINE_CMD_DEFN *defn, const char *s)
    {
    int idx = 0;
    while(!int_ctrl_cmd_is_null(defn) && (strcmp(defn->cmd_name, s) != 0))
        {
        idx++;
        defn++;
        }
    if(int_ctrl_cmd_is_null(defn))
        /* The given name wasn't found */
        return -1;
    return idx;
    }

static int int_ctrl_cmd_by_num(const ENGINE_CMD_DEFN *defn, unsigned int num)
    {
    int idx = 0;
    /* NB: It is stipulated that 'cmd_defn' lists are ordered by cmd_num. So
     * our searches don't need to take any longer than necessary. */
    while(!int_ctrl_cmd_is_null(defn) && (defn->cmd_num < num))
        {
        idx++;
        defn++;
        }
    if(defn->cmd_num == num)
        return idx;
    /* The given cmd_num wasn't found */
    return -1;
    }

static int int_ctrl_helper(ENGINE *e, int cmd, long i, void *p,
               void (*f)(void))
    {
    int idx;
    char *s = (char *)p;
    /* Take care of the easy one first (eg. it requires no searches) */
    if(cmd == ENGINE_CTRL_GET_FIRST_CMD_TYPE)
        {
        if((e->cmd_defns == NULL) || int_ctrl_cmd_is_null(e->cmd_defns))
            return 0;
        return e->cmd_defns->cmd_num;
        }
    /* One or two commands require that "p" be a valid string buffer */
    if((cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) ||
            (cmd == ENGINE_CTRL_GET_NAME_FROM_CMD) ||
            (cmd == ENGINE_CTRL_GET_DESC_FROM_CMD))
        {
        if(s == NULL)
            {
            ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
                ERR_R_PASSED_NULL_PARAMETER);
            return -1;
            }
        }
    /* Now handle cmd_name -> cmd_num conversion */
    if(cmd == ENGINE_CTRL_GET_CMD_FROM_NAME)
        {
        if((e->cmd_defns == NULL) || ((idx = int_ctrl_cmd_by_name(
                        e->cmd_defns, s)) < 0))
            {
            ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
                ENGINE_R_INVALID_CMD_NAME);
            return -1;
            }
        return e->cmd_defns[idx].cmd_num;
        }
    /* For the rest of the commands, the 'long' argument must specify a
     * valie command number - so we need to conduct a search. */
    if((e->cmd_defns == NULL) || ((idx = int_ctrl_cmd_by_num(e->cmd_defns,
                    (unsigned int)i)) < 0))
        {
        ENGINEerr(ENGINE_F_INT_CTRL_HELPER,
            ENGINE_R_INVALID_CMD_NUMBER);
        return -1;
        }
    /* Now the logic splits depending on command type */
    switch(cmd)
        {
    case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
        idx++;
        if(int_ctrl_cmd_is_null(e->cmd_defns + idx))
            /* end-of-list */
            return 0;
        else
            return e->cmd_defns[idx].cmd_num;
    case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
        return strlen(e->cmd_defns[idx].cmd_name);
    case ENGINE_CTRL_GET_NAME_FROM_CMD:
        return BIO_snprintf(s,strlen(e->cmd_defns[idx].cmd_name) + 1,
                    "%s", e->cmd_defns[idx].cmd_name);
    case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
        if(e->cmd_defns[idx].cmd_desc)
            return strlen(e->cmd_defns[idx].cmd_desc);
        return strlen(int_no_description);
    case ENGINE_CTRL_GET_DESC_FROM_CMD:
        if(e->cmd_defns[idx].cmd_desc)
            return BIO_snprintf(s,
                        strlen(e->cmd_defns[idx].cmd_desc) + 1,
                        "%s", e->cmd_defns[idx].cmd_desc);
        return BIO_snprintf(s, strlen(int_no_description) + 1,"%s",
                    int_no_description);
    case ENGINE_CTRL_GET_CMD_FLAGS:
        return e->cmd_defns[idx].cmd_flags;
        }
    /* Shouldn't really be here ... */
    ENGINEerr(ENGINE_F_INT_CTRL_HELPER,ENGINE_R_INTERNAL_LIST_ERROR);
    return -1;
    }

int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)(void))
    {
    int ctrl_exists, ref_exists;
    if(e == NULL)
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL,ERR_R_PASSED_NULL_PARAMETER);
        return 0;
        }
    CRYPTO_w_lock(CRYPTO_LOCK_ENGINE);
    ref_exists = ((e->struct_ref > 0) ? 1 : 0);
    CRYPTO_w_unlock(CRYPTO_LOCK_ENGINE);
    ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
    if(!ref_exists)
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL,ENGINE_R_NO_REFERENCE);
        return 0;
        }
    /* Intercept any "root-level" commands before trying to hand them on to
     * ctrl() handlers. */
    switch(cmd)
        {
    case ENGINE_CTRL_HAS_CTRL_FUNCTION:
        return ctrl_exists;
    case ENGINE_CTRL_GET_FIRST_CMD_TYPE:
    case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
    case ENGINE_CTRL_GET_CMD_FROM_NAME:
    case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
    case ENGINE_CTRL_GET_NAME_FROM_CMD:
    case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
    case ENGINE_CTRL_GET_DESC_FROM_CMD:
    case ENGINE_CTRL_GET_CMD_FLAGS:
        if(ctrl_exists && !(e->flags & ENGINE_FLAGS_MANUAL_CMD_CTRL))
            return int_ctrl_helper(e,cmd,i,p,f);
        if(!ctrl_exists)
            {
            ENGINEerr(ENGINE_F_ENGINE_CTRL,ENGINE_R_NO_CONTROL_FUNCTION);
            /* For these cmd-related functions, failure is indicated
             * by a -1 return value (because 0 is used as a valid
             * return in some places). */
            return -1;
            }
    default:
        break;
        }
    /* Anything else requires a ctrl() handler to exist. */
    if(!ctrl_exists)
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL,ENGINE_R_NO_CONTROL_FUNCTION);
        return 0;
        }
    return e->ctrl(e, cmd, i, p, f);
    }

int ENGINE_cmd_is_executable(ENGINE *e, int cmd)
    {
    int flags;
    if((flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, cmd, NULL, NULL)) < 0)
        {
        ENGINEerr(ENGINE_F_ENGINE_CMD_IS_EXECUTABLE,
            ENGINE_R_INVALID_CMD_NUMBER);
        return 0;
        }
    if(!(flags & ENGINE_CMD_FLAG_NO_INPUT) &&
            !(flags & ENGINE_CMD_FLAG_NUMERIC) &&
            !(flags & ENGINE_CMD_FLAG_STRING))
        return 0;
    return 1;
    }

int ENGINE_ctrl_cmd(ENGINE *e, const char *cmd_name,
        long i, void *p, void (*f)(void), int cmd_optional)
        {
    int num;

    if((e == NULL) || (cmd_name == NULL))
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD,
            ERR_R_PASSED_NULL_PARAMETER);
        return 0;
        }
    if((e->ctrl == NULL) || ((num = ENGINE_ctrl(e,
                    ENGINE_CTRL_GET_CMD_FROM_NAME,
                    0, (void *)cmd_name, NULL)) <= 0))
        {
        /* If the command didn't *have* to be supported, we fake
         * success. This allows certain settings to be specified for
         * multiple ENGINEs and only require a change of ENGINE id
         * (without having to selectively apply settings). Eg. changing
         * from a hardware device back to the regular software ENGINE
         * without editing the config file, etc. */
        if(cmd_optional)
            {
            ERR_clear_error();
            return 1;
            }
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD,
            ENGINE_R_INVALID_CMD_NAME);
        return 0;
        }
    /* Force the result of the control command to 0 or 1, for the reasons
     * mentioned before. */
        if (ENGINE_ctrl(e, num, i, p, f) > 0)
                return 1;
        return 0;
        }

int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
                int cmd_optional)
    {
    int num, flags;
    long l;
    char *ptr;
    if((e == NULL) || (cmd_name == NULL))
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ERR_R_PASSED_NULL_PARAMETER);
        return 0;
        }
    if((e->ctrl == NULL) || ((num = ENGINE_ctrl(e,
                    ENGINE_CTRL_GET_CMD_FROM_NAME,
                    0, (void *)cmd_name, NULL)) <= 0))
        {
        /* If the command didn't *have* to be supported, we fake
         * success. This allows certain settings to be specified for
         * multiple ENGINEs and only require a change of ENGINE id
         * (without having to selectively apply settings). Eg. changing
         * from a hardware device back to the regular software ENGINE
         * without editing the config file, etc. */
        if(cmd_optional)
            {
            ERR_clear_error();
            return 1;
            }
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_INVALID_CMD_NAME);
        return 0;
        }
    if(!ENGINE_cmd_is_executable(e, num))
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_CMD_NOT_EXECUTABLE);
        return 0;
        }
    if((flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL)) < 0)
        {
        /* Shouldn't happen, given that ENGINE_cmd_is_executable()
         * returned success. */
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_INTERNAL_LIST_ERROR);
        return 0;
        }
    /* If the command takes no input, there must be no input. And vice
     * versa. */
    if(flags & ENGINE_CMD_FLAG_NO_INPUT)
        {
        if(arg != NULL)
            {
            ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
                ENGINE_R_COMMAND_TAKES_NO_INPUT);
            return 0;
            }
        /* We deliberately force the result of ENGINE_ctrl() to 0 or 1
         * rather than returning it as "return data". This is to ensure
         * usage of these commands is consistent across applications and
         * that certain applications don't understand it one way, and
         * others another. */
        if(ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
            return 1;
        return 0;
        }
    /* So, we require input */
    if(arg == NULL)
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_COMMAND_TAKES_INPUT);
        return 0;
        }
    /* If it takes string input, that's easy */
    if(flags & ENGINE_CMD_FLAG_STRING)
        {
        /* Same explanation as above */
        if(ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
            return 1;
        return 0;
        }
    /* If it doesn't take numeric either, then it is unsupported for use in
     * a config-setting situation, which is what this function is for. This
     * should never happen though, because ENGINE_cmd_is_executable() was
     * used. */
    if(!(flags & ENGINE_CMD_FLAG_NUMERIC))
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_INTERNAL_LIST_ERROR);
        return 0;
        }
    l = strtol(arg, &ptr, 10);
    if((arg == ptr) || (*ptr != '\0'))
        {
        ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
            ENGINE_R_ARGUMENT_IS_NOT_A_NUMBER);
        return 0;
        }
    /* Force the result of the control command to 0 or 1, for the reasons
     * mentioned before. */
    if(ENGINE_ctrl(e, num, l, NULL, NULL) > 0)
        return 1;
    return 0;
    }