3bc4aab16feda64822abc43bdc692701413e1c6c
[openssl.git] / crypto / engine / eng_ctrl.c
1 /*
2  * Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9
10 #include "eng_int.h"
11
12 /*
13  * When querying a ENGINE-specific control command's 'description', this
14  * string is used if the ENGINE_CMD_DEFN has cmd_desc set to NULL.
15  */
16 static const char *int_no_description = "";
17
18 /*
19  * These internal functions handle 'CMD'-related control commands when the
20  * ENGINE in question has asked us to take care of it (ie. the ENGINE did not
21  * set the ENGINE_FLAGS_MANUAL_CMD_CTRL flag.
22  */
23
24 static int int_ctrl_cmd_is_null(const ENGINE_CMD_DEFN *defn)
25 {
26     if ((defn->cmd_num == 0) || (defn->cmd_name == NULL))
27         return 1;
28     return 0;
29 }
30
31 static int int_ctrl_cmd_by_name(const ENGINE_CMD_DEFN *defn, const char *s)
32 {
33     int idx = 0;
34     while (!int_ctrl_cmd_is_null(defn) && (strcmp(defn->cmd_name, s) != 0)) {
35         idx++;
36         defn++;
37     }
38     if (int_ctrl_cmd_is_null(defn))
39         /* The given name wasn't found */
40         return -1;
41     return idx;
42 }
43
44 static int int_ctrl_cmd_by_num(const ENGINE_CMD_DEFN *defn, unsigned int num)
45 {
46     int idx = 0;
47     /*
48      * NB: It is stipulated that 'cmd_defn' lists are ordered by cmd_num. So
49      * our searches don't need to take any longer than necessary.
50      */
51     while (!int_ctrl_cmd_is_null(defn) && (defn->cmd_num < num)) {
52         idx++;
53         defn++;
54     }
55     if (defn->cmd_num == num)
56         return idx;
57     /* The given cmd_num wasn't found */
58     return -1;
59 }
60
61 static int int_ctrl_helper(ENGINE *e, int cmd, long i, void *p,
62                            void (*f) (void))
63 {
64     int idx;
65     char *s = (char *)p;
66     const ENGINE_CMD_DEFN *cdp;
67
68     /* Take care of the easy one first (eg. it requires no searches) */
69     if (cmd == ENGINE_CTRL_GET_FIRST_CMD_TYPE) {
70         if ((e->cmd_defns == NULL) || int_ctrl_cmd_is_null(e->cmd_defns))
71             return 0;
72         return e->cmd_defns->cmd_num;
73     }
74     /* One or two commands require that "p" be a valid string buffer */
75     if ((cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) ||
76         (cmd == ENGINE_CTRL_GET_NAME_FROM_CMD) ||
77         (cmd == ENGINE_CTRL_GET_DESC_FROM_CMD)) {
78         if (s == NULL) {
79             ENGINEerr(ENGINE_F_INT_CTRL_HELPER, ERR_R_PASSED_NULL_PARAMETER);
80             return -1;
81         }
82     }
83     /* Now handle cmd_name -> cmd_num conversion */
84     if (cmd == ENGINE_CTRL_GET_CMD_FROM_NAME) {
85         if ((e->cmd_defns == NULL)
86             || ((idx = int_ctrl_cmd_by_name(e->cmd_defns, s)) < 0)) {
87             ENGINEerr(ENGINE_F_INT_CTRL_HELPER, ENGINE_R_INVALID_CMD_NAME);
88             return -1;
89         }
90         return e->cmd_defns[idx].cmd_num;
91     }
92     /*
93      * For the rest of the commands, the 'long' argument must specify a valid
94      * command number - so we need to conduct a search.
95      */
96     if ((e->cmd_defns == NULL)
97         || ((idx = int_ctrl_cmd_by_num(e->cmd_defns, (unsigned int)i)) < 0)) {
98         ENGINEerr(ENGINE_F_INT_CTRL_HELPER, ENGINE_R_INVALID_CMD_NUMBER);
99         return -1;
100     }
101     /* Now the logic splits depending on command type */
102     cdp = &e->cmd_defns[idx];
103     switch (cmd) {
104     case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
105         cdp++;
106         return int_ctrl_cmd_is_null(cdp) ? 0 : cdp->cmd_num;
107     case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
108         return strlen(cdp->cmd_name);
109     case ENGINE_CTRL_GET_NAME_FROM_CMD:
110         return strlen(strcpy(s, cdp->cmd_name));
111     case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
112         return strlen(cdp->cmd_desc == NULL ? int_no_description
113                                             : cdp->cmd_desc);
114     case ENGINE_CTRL_GET_DESC_FROM_CMD:
115         return strlen(strcpy(s, cdp->cmd_desc == NULL ? int_no_description
116                                                       : cdp->cmd_desc));
117     case ENGINE_CTRL_GET_CMD_FLAGS:
118         return cdp->cmd_flags;
119     }
120     /* Shouldn't really be here ... */
121     ENGINEerr(ENGINE_F_INT_CTRL_HELPER, ENGINE_R_INTERNAL_LIST_ERROR);
122     return -1;
123 }
124
125 int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
126 {
127     int ctrl_exists, ref_exists;
128     if (e == NULL) {
129         ENGINEerr(ENGINE_F_ENGINE_CTRL, ERR_R_PASSED_NULL_PARAMETER);
130         return 0;
131     }
132     CRYPTO_THREAD_write_lock(global_engine_lock);
133     ref_exists = ((e->struct_ref > 0) ? 1 : 0);
134     CRYPTO_THREAD_unlock(global_engine_lock);
135     ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
136     if (!ref_exists) {
137         ENGINEerr(ENGINE_F_ENGINE_CTRL, ENGINE_R_NO_REFERENCE);
138         return 0;
139     }
140     /*
141      * Intercept any "root-level" commands before trying to hand them on to
142      * ctrl() handlers.
143      */
144     switch (cmd) {
145     case ENGINE_CTRL_HAS_CTRL_FUNCTION:
146         return ctrl_exists;
147     case ENGINE_CTRL_GET_FIRST_CMD_TYPE:
148     case ENGINE_CTRL_GET_NEXT_CMD_TYPE:
149     case ENGINE_CTRL_GET_CMD_FROM_NAME:
150     case ENGINE_CTRL_GET_NAME_LEN_FROM_CMD:
151     case ENGINE_CTRL_GET_NAME_FROM_CMD:
152     case ENGINE_CTRL_GET_DESC_LEN_FROM_CMD:
153     case ENGINE_CTRL_GET_DESC_FROM_CMD:
154     case ENGINE_CTRL_GET_CMD_FLAGS:
155         if (ctrl_exists && !(e->flags & ENGINE_FLAGS_MANUAL_CMD_CTRL))
156             return int_ctrl_helper(e, cmd, i, p, f);
157         if (!ctrl_exists) {
158             ENGINEerr(ENGINE_F_ENGINE_CTRL, ENGINE_R_NO_CONTROL_FUNCTION);
159             /*
160              * For these cmd-related functions, failure is indicated by a -1
161              * return value (because 0 is used as a valid return in some
162              * places).
163              */
164             return -1;
165         }
166     default:
167         break;
168     }
169     /* Anything else requires a ctrl() handler to exist. */
170     if (!ctrl_exists) {
171         ENGINEerr(ENGINE_F_ENGINE_CTRL, ENGINE_R_NO_CONTROL_FUNCTION);
172         return 0;
173     }
174     return e->ctrl(e, cmd, i, p, f);
175 }
176
177 int ENGINE_cmd_is_executable(ENGINE *e, int cmd)
178 {
179     int flags;
180     if ((flags =
181          ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, cmd, NULL, NULL)) < 0) {
182         ENGINEerr(ENGINE_F_ENGINE_CMD_IS_EXECUTABLE,
183                   ENGINE_R_INVALID_CMD_NUMBER);
184         return 0;
185     }
186     if (!(flags & ENGINE_CMD_FLAG_NO_INPUT) &&
187         !(flags & ENGINE_CMD_FLAG_NUMERIC) &&
188         !(flags & ENGINE_CMD_FLAG_STRING))
189         return 0;
190     return 1;
191 }
192
193 int ENGINE_ctrl_cmd(ENGINE *e, const char *cmd_name,
194                     long i, void *p, void (*f) (void), int cmd_optional)
195 {
196     int num;
197
198     if (e == NULL || cmd_name == NULL) {
199         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD, ERR_R_PASSED_NULL_PARAMETER);
200         return 0;
201     }
202     if (e->ctrl == NULL
203         || (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
204                               0, (void *)cmd_name, NULL)) <= 0) {
205         /*
206          * If the command didn't *have* to be supported, we fake success.
207          * This allows certain settings to be specified for multiple ENGINEs
208          * and only require a change of ENGINE id (without having to
209          * selectively apply settings). Eg. changing from a hardware device
210          * back to the regular software ENGINE without editing the config
211          * file, etc.
212          */
213         if (cmd_optional) {
214             ERR_clear_error();
215             return 1;
216         }
217         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD, ENGINE_R_INVALID_CMD_NAME);
218         return 0;
219     }
220     /*
221      * Force the result of the control command to 0 or 1, for the reasons
222      * mentioned before.
223      */
224     if (ENGINE_ctrl(e, num, i, p, f) > 0)
225         return 1;
226     return 0;
227 }
228
229 int ENGINE_ctrl_cmd_string(ENGINE *e, const char *cmd_name, const char *arg,
230                            int cmd_optional)
231 {
232     int num, flags;
233     long l;
234     char *ptr;
235
236     if (e == NULL || cmd_name == NULL) {
237         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING, ERR_R_PASSED_NULL_PARAMETER);
238         return 0;
239     }
240     if (e->ctrl == NULL
241         || (num = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FROM_NAME,
242                               0, (void *)cmd_name, NULL)) <= 0) {
243         /*
244          * If the command didn't *have* to be supported, we fake success.
245          * This allows certain settings to be specified for multiple ENGINEs
246          * and only require a change of ENGINE id (without having to
247          * selectively apply settings). Eg. changing from a hardware device
248          * back to the regular software ENGINE without editing the config
249          * file, etc.
250          */
251         if (cmd_optional) {
252             ERR_clear_error();
253             return 1;
254         }
255         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING, ENGINE_R_INVALID_CMD_NAME);
256         return 0;
257     }
258     if (!ENGINE_cmd_is_executable(e, num)) {
259         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
260                   ENGINE_R_CMD_NOT_EXECUTABLE);
261         return 0;
262     }
263
264     flags = ENGINE_ctrl(e, ENGINE_CTRL_GET_CMD_FLAGS, num, NULL, NULL);
265     if (flags < 0) {
266         /*
267          * Shouldn't happen, given that ENGINE_cmd_is_executable() returned
268          * success.
269          */
270         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
271                   ENGINE_R_INTERNAL_LIST_ERROR);
272         return 0;
273     }
274     /*
275      * If the command takes no input, there must be no input. And vice versa.
276      */
277     if (flags & ENGINE_CMD_FLAG_NO_INPUT) {
278         if (arg != NULL) {
279             ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
280                       ENGINE_R_COMMAND_TAKES_NO_INPUT);
281             return 0;
282         }
283         /*
284          * We deliberately force the result of ENGINE_ctrl() to 0 or 1 rather
285          * than returning it as "return data". This is to ensure usage of
286          * these commands is consistent across applications and that certain
287          * applications don't understand it one way, and others another.
288          */
289         if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
290             return 1;
291         return 0;
292     }
293     /* So, we require input */
294     if (arg == NULL) {
295         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
296                   ENGINE_R_COMMAND_TAKES_INPUT);
297         return 0;
298     }
299     /* If it takes string input, that's easy */
300     if (flags & ENGINE_CMD_FLAG_STRING) {
301         /* Same explanation as above */
302         if (ENGINE_ctrl(e, num, 0, (void *)arg, NULL) > 0)
303             return 1;
304         return 0;
305     }
306     /*
307      * If it doesn't take numeric either, then it is unsupported for use in a
308      * config-setting situation, which is what this function is for. This
309      * should never happen though, because ENGINE_cmd_is_executable() was
310      * used.
311      */
312     if (!(flags & ENGINE_CMD_FLAG_NUMERIC)) {
313         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
314                   ENGINE_R_INTERNAL_LIST_ERROR);
315         return 0;
316     }
317     l = strtol(arg, &ptr, 10);
318     if ((arg == ptr) || (*ptr != '\0')) {
319         ENGINEerr(ENGINE_F_ENGINE_CTRL_CMD_STRING,
320                   ENGINE_R_ARGUMENT_IS_NOT_A_NUMBER);
321         return 0;
322     }
323     /*
324      * Force the result of the control command to 0 or 1, for the reasons
325      * mentioned before.
326      */
327     if (ENGINE_ctrl(e, num, l, NULL, NULL) > 0)
328         return 1;
329     return 0;
330 }