1 /*
2 * Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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 /* Dispatch functions for gcm mode */
11
12 #include <openssl/rand.h>
13 #include <openssl/proverr.h>
14 #include "prov/ciphercommon.h"
15 #include "prov/ciphercommon_gcm.h"
16 #include "prov/providercommon.h"
17 #include "prov/provider_ctx.h"
18
19 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len);
20 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
21 size_t len);
22 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
23 const unsigned char *in, size_t len);
24 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
25 size_t *padlen, const unsigned char *in,
26 size_t len);
27
28 /*
29 * Called from EVP_CipherInit when there is currently no context via
30 * the new_ctx() function
31 */
ossl_gcm_initctx(void * provctx,PROV_GCM_CTX * ctx,size_t keybits,const PROV_GCM_HW * hw)32 void ossl_gcm_initctx(void *provctx, PROV_GCM_CTX *ctx, size_t keybits,
33 const PROV_GCM_HW *hw)
34 {
35 ctx->pad = 1;
36 ctx->mode = EVP_CIPH_GCM_MODE;
37 ctx->taglen = UNINITIALISED_SIZET;
38 ctx->tls_aad_len = UNINITIALISED_SIZET;
39 ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN);
40 ctx->keylen = keybits / 8;
41 ctx->hw = hw;
42 ctx->libctx = PROV_LIBCTX_OF(provctx);
43 }
44
45 /*
46 * Called by EVP_CipherInit via the _einit and _dinit functions
47 */
gcm_init(void * vctx,const unsigned char * key,size_t keylen,const unsigned char * iv,size_t ivlen,const OSSL_PARAM params[],int enc)48 static int gcm_init(void *vctx, const unsigned char *key, size_t keylen,
49 const unsigned char *iv, size_t ivlen,
50 const OSSL_PARAM params[], int enc)
51 {
52 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
53
54 if (!ossl_prov_is_running())
55 return 0;
56
57 ctx->enc = enc;
58
59 if (iv != NULL) {
60 if (ivlen == 0 || ivlen > sizeof(ctx->iv)) {
61 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
62 return 0;
63 }
64 ctx->ivlen = ivlen;
65 memcpy(ctx->iv, iv, ivlen);
66 ctx->iv_state = IV_STATE_BUFFERED;
67 }
68
69 if (key != NULL) {
70 if (keylen != ctx->keylen) {
71 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
72 return 0;
73 }
74 if (!ctx->hw->setkey(ctx, key, ctx->keylen))
75 return 0;
76 ctx->tls_enc_records = 0;
77 }
78 return ossl_gcm_set_ctx_params(ctx, params);
79 }
80
ossl_gcm_einit(void * vctx,const unsigned char * key,size_t keylen,const unsigned char * iv,size_t ivlen,const OSSL_PARAM params[])81 int ossl_gcm_einit(void *vctx, const unsigned char *key, size_t keylen,
82 const unsigned char *iv, size_t ivlen,
83 const OSSL_PARAM params[])
84 {
85 return gcm_init(vctx, key, keylen, iv, ivlen, params, 1);
86 }
87
ossl_gcm_dinit(void * vctx,const unsigned char * key,size_t keylen,const unsigned char * iv,size_t ivlen,const OSSL_PARAM params[])88 int ossl_gcm_dinit(void *vctx, const unsigned char *key, size_t keylen,
89 const unsigned char *iv, size_t ivlen,
90 const OSSL_PARAM params[])
91 {
92 return gcm_init(vctx, key, keylen, iv, ivlen, params, 0);
93 }
94
95 /* increment counter (64-bit int) by 1 */
ctr64_inc(unsigned char * counter)96 static void ctr64_inc(unsigned char *counter)
97 {
98 int n = 8;
99 unsigned char c;
100
101 do {
102 --n;
103 c = counter[n];
104 ++c;
105 counter[n] = c;
106 if (c > 0)
107 return;
108 } while (n > 0);
109 }
110
getivgen(PROV_GCM_CTX * ctx,unsigned char * out,size_t olen)111 static int getivgen(PROV_GCM_CTX *ctx, unsigned char *out, size_t olen)
112 {
113 if (!ctx->iv_gen
114 || !ctx->key_set
115 || !ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
116 return 0;
117 if (olen == 0 || olen > ctx->ivlen)
118 olen = ctx->ivlen;
119 memcpy(out, ctx->iv + ctx->ivlen - olen, olen);
120 /*
121 * Invocation field will be at least 8 bytes in size and so no need
122 * to check wrap around or increment more than last 8 bytes.
123 */
124 ctr64_inc(ctx->iv + ctx->ivlen - 8);
125 ctx->iv_state = IV_STATE_COPIED;
126 return 1;
127 }
128
setivinv(PROV_GCM_CTX * ctx,unsigned char * in,size_t inl)129 static int setivinv(PROV_GCM_CTX *ctx, unsigned char *in, size_t inl)
130 {
131 if (!ctx->iv_gen
132 || !ctx->key_set
133 || ctx->enc)
134 return 0;
135
136 memcpy(ctx->iv + ctx->ivlen - inl, in, inl);
137 if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
138 return 0;
139 ctx->iv_state = IV_STATE_COPIED;
140 return 1;
141 }
142
ossl_gcm_get_ctx_params(void * vctx,OSSL_PARAM params[])143 int ossl_gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
144 {
145 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
146 OSSL_PARAM *p;
147 size_t sz;
148
149 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IVLEN);
150 if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->ivlen)) {
151 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
152 return 0;
153 }
154 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_KEYLEN);
155 if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->keylen)) {
156 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
157 return 0;
158 }
159 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TAGLEN);
160 if (p != NULL) {
161 size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen :
162 GCM_TAG_MAX_SIZE;
163
164 if (!OSSL_PARAM_set_size_t(p, taglen)) {
165 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
166 return 0;
167 }
168 }
169
170 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IV);
171 if (p != NULL) {
172 if (ctx->iv_state == IV_STATE_UNINITIALISED)
173 return 0;
174 if (ctx->ivlen > p->data_size) {
175 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
176 return 0;
177 }
178 if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen)
179 && !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) {
180 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
181 return 0;
182 }
183 }
184
185 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_UPDATED_IV);
186 if (p != NULL) {
187 if (ctx->iv_state == IV_STATE_UNINITIALISED)
188 return 0;
189 if (ctx->ivlen > p->data_size) {
190 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
191 return 0;
192 }
193 if (!OSSL_PARAM_set_octet_string(p, ctx->iv, ctx->ivlen)
194 && !OSSL_PARAM_set_octet_ptr(p, &ctx->iv, ctx->ivlen)) {
195 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
196 return 0;
197 }
198 }
199
200 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TLS1_AAD_PAD);
201 if (p != NULL && !OSSL_PARAM_set_size_t(p, ctx->tls_aad_pad_sz)) {
202 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
203 return 0;
204 }
205 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TAG);
206 if (p != NULL) {
207 sz = p->data_size;
208 if (sz == 0
209 || sz > EVP_GCM_TLS_TAG_LEN
210 || !ctx->enc
211 || ctx->taglen == UNINITIALISED_SIZET) {
212 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
213 return 0;
214 }
215 if (!OSSL_PARAM_set_octet_string(p, ctx->buf, sz)) {
216 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
217 return 0;
218 }
219 }
220 p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_AEAD_TLS1_GET_IV_GEN);
221 if (p != NULL) {
222 if (p->data == NULL
223 || p->data_type != OSSL_PARAM_OCTET_STRING
224 || !getivgen(ctx, p->data, p->data_size))
225 return 0;
226 }
227 return 1;
228 }
229
ossl_gcm_set_ctx_params(void * vctx,const OSSL_PARAM params[])230 int ossl_gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[])
231 {
232 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
233 const OSSL_PARAM *p;
234 size_t sz;
235 void *vp;
236
237 if (params == NULL)
238 return 1;
239
240 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TAG);
241 if (p != NULL) {
242 vp = ctx->buf;
243 if (!OSSL_PARAM_get_octet_string(p, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) {
244 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
245 return 0;
246 }
247 if (sz == 0 || ctx->enc) {
248 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
249 return 0;
250 }
251 ctx->taglen = sz;
252 }
253
254 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_IVLEN);
255 if (p != NULL) {
256 if (!OSSL_PARAM_get_size_t(p, &sz)) {
257 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
258 return 0;
259 }
260 if (sz == 0 || sz > sizeof(ctx->iv)) {
261 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
262 return 0;
263 }
264 ctx->ivlen = sz;
265 }
266
267 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TLS1_AAD);
268 if (p != NULL) {
269 if (p->data_type != OSSL_PARAM_OCTET_STRING) {
270 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
271 return 0;
272 }
273 sz = gcm_tls_init(ctx, p->data, p->data_size);
274 if (sz == 0) {
275 ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD);
276 return 0;
277 }
278 ctx->tls_aad_pad_sz = sz;
279 }
280
281 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TLS1_IV_FIXED);
282 if (p != NULL) {
283 if (p->data_type != OSSL_PARAM_OCTET_STRING) {
284 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
285 return 0;
286 }
287 if (gcm_tls_iv_set_fixed(ctx, p->data, p->data_size) == 0) {
288 ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
289 return 0;
290 }
291 }
292 p = OSSL_PARAM_locate_const(params, OSSL_CIPHER_PARAM_AEAD_TLS1_SET_IV_INV);
293 if (p != NULL) {
294 if (p->data == NULL
295 || p->data_type != OSSL_PARAM_OCTET_STRING
296 || !setivinv(ctx, p->data, p->data_size))
297 return 0;
298 }
299
300
301 return 1;
302 }
303
ossl_gcm_stream_update(void * vctx,unsigned char * out,size_t * outl,size_t outsize,const unsigned char * in,size_t inl)304 int ossl_gcm_stream_update(void *vctx, unsigned char *out, size_t *outl,
305 size_t outsize, const unsigned char *in, size_t inl)
306 {
307 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
308
309 if (inl == 0) {
310 *outl = 0;
311 return 1;
312 }
313
314 if (outsize < inl) {
315 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
316 return 0;
317 }
318
319 if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0) {
320 ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
321 return 0;
322 }
323 return 1;
324 }
325
ossl_gcm_stream_final(void * vctx,unsigned char * out,size_t * outl,size_t outsize)326 int ossl_gcm_stream_final(void *vctx, unsigned char *out, size_t *outl,
327 size_t outsize)
328 {
329 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
330 int i;
331
332 if (!ossl_prov_is_running())
333 return 0;
334
335 i = gcm_cipher_internal(ctx, out, outl, NULL, 0);
336 if (i <= 0)
337 return 0;
338
339 *outl = 0;
340 return 1;
341 }
342
ossl_gcm_cipher(void * vctx,unsigned char * out,size_t * outl,size_t outsize,const unsigned char * in,size_t inl)343 int ossl_gcm_cipher(void *vctx,
344 unsigned char *out, size_t *outl, size_t outsize,
345 const unsigned char *in, size_t inl)
346 {
347 PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
348
349 if (!ossl_prov_is_running())
350 return 0;
351
352 if (outsize < inl) {
353 ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
354 return 0;
355 }
356
357 if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
358 return 0;
359
360 *outl = inl;
361 return 1;
362 }
363
364 /*
365 * See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys"
366 *
367 * See also 8.2.2 RBG-based construction.
368 * Random construction consists of a free field (which can be NULL) and a
369 * random field which will use a DRBG that can return at least 96 bits of
370 * entropy strength. (The DRBG must be seeded by the FIPS module).
371 */
gcm_iv_generate(PROV_GCM_CTX * ctx,int offset)372 static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset)
373 {
374 int sz = ctx->ivlen - offset;
375
376 /* Must be at least 96 bits */
377 if (sz <= 0 || ctx->ivlen < GCM_IV_DEFAULT_SIZE)
378 return 0;
379
380 /* Use DRBG to generate random iv */
381 if (RAND_bytes_ex(ctx->libctx, ctx->iv + offset, sz, 0) <= 0)
382 return 0;
383 ctx->iv_state = IV_STATE_BUFFERED;
384 ctx->iv_gen_rand = 1;
385 return 1;
386 }
387
gcm_cipher_internal(PROV_GCM_CTX * ctx,unsigned char * out,size_t * padlen,const unsigned char * in,size_t len)388 static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
389 size_t *padlen, const unsigned char *in,
390 size_t len)
391 {
392 size_t olen = 0;
393 int rv = 0;
394 const PROV_GCM_HW *hw = ctx->hw;
395
396 if (ctx->tls_aad_len != UNINITIALISED_SIZET)
397 return gcm_tls_cipher(ctx, out, padlen, in, len);
398
399 if (!ctx->key_set || ctx->iv_state == IV_STATE_FINISHED)
400 goto err;
401
402 /*
403 * FIPS requires generation of AES-GCM IV's inside the FIPS module.
404 * The IV can still be set externally (the security policy will state that
405 * this is not FIPS compliant). There are some applications
406 * where setting the IV externally is the only option available.
407 */
408 if (ctx->iv_state == IV_STATE_UNINITIALISED) {
409 if (!ctx->enc || !gcm_iv_generate(ctx, 0))
410 goto err;
411 }
412
413 if (ctx->iv_state == IV_STATE_BUFFERED) {
414 if (!hw->setiv(ctx, ctx->iv, ctx->ivlen))
415 goto err;
416 ctx->iv_state = IV_STATE_COPIED;
417 }
418
419 if (in != NULL) {
420 /* The input is AAD if out is NULL */
421 if (out == NULL) {
422 if (!hw->aadupdate(ctx, in, len))
423 goto err;
424 } else {
425 /* The input is ciphertext OR plaintext */
426 if (!hw->cipherupdate(ctx, in, len, out))
427 goto err;
428 }
429 } else {
430 /* The tag must be set before actually decrypting data */
431 if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET)
432 goto err;
433 if (!hw->cipherfinal(ctx, ctx->buf))
434 goto err;
435 ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */
436 goto finish;
437 }
438 olen = len;
439 finish:
440 rv = 1;
441 err:
442 *padlen = olen;
443 return rv;
444 }
445
gcm_tls_init(PROV_GCM_CTX * dat,unsigned char * aad,size_t aad_len)446 static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len)
447 {
448 unsigned char *buf;
449 size_t len;
450
451 if (!ossl_prov_is_running() || aad_len != EVP_AEAD_TLS1_AAD_LEN)
452 return 0;
453
454 /* Save the aad for later use. */
455 buf = dat->buf;
456 memcpy(buf, aad, aad_len);
457 dat->tls_aad_len = aad_len;
458
459 len = buf[aad_len - 2] << 8 | buf[aad_len - 1];
460 /* Correct length for explicit iv. */
461 if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN)
462 return 0;
463 len -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
464
465 /* If decrypting correct for tag too. */
466 if (!dat->enc) {
467 if (len < EVP_GCM_TLS_TAG_LEN)
468 return 0;
469 len -= EVP_GCM_TLS_TAG_LEN;
470 }
471 buf[aad_len - 2] = (unsigned char)(len >> 8);
472 buf[aad_len - 1] = (unsigned char)(len & 0xff);
473 /* Extra padding: tag appended to record. */
474 return EVP_GCM_TLS_TAG_LEN;
475 }
476
gcm_tls_iv_set_fixed(PROV_GCM_CTX * ctx,unsigned char * iv,size_t len)477 static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
478 size_t len)
479 {
480 /* Special case: -1 length restores whole IV */
481 if (len == (size_t)-1) {
482 memcpy(ctx->iv, iv, ctx->ivlen);
483 ctx->iv_gen = 1;
484 ctx->iv_state = IV_STATE_BUFFERED;
485 return 1;
486 }
487 /* Fixed field must be at least 4 bytes and invocation field at least 8 */
488 if ((len < EVP_GCM_TLS_FIXED_IV_LEN)
489 || (ctx->ivlen - (int)len) < EVP_GCM_TLS_EXPLICIT_IV_LEN)
490 return 0;
491 if (len > 0)
492 memcpy(ctx->iv, iv, len);
493 if (ctx->enc
494 && RAND_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len, 0) <= 0)
495 return 0;
496 ctx->iv_gen = 1;
497 ctx->iv_state = IV_STATE_BUFFERED;
498 return 1;
499 }
500
501 /*
502 * Handle TLS GCM packet format. This consists of the last portion of the IV
503 * followed by the payload and finally the tag. On encrypt generate IV,
504 * encrypt payload and write the tag. On verify retrieve IV, decrypt payload
505 * and verify tag.
506 */
gcm_tls_cipher(PROV_GCM_CTX * ctx,unsigned char * out,size_t * padlen,const unsigned char * in,size_t len)507 static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
508 const unsigned char *in, size_t len)
509 {
510 int rv = 0;
511 size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN;
512 size_t plen = 0;
513 unsigned char *tag = NULL;
514
515 if (!ossl_prov_is_running() || !ctx->key_set)
516 goto err;
517
518 /* Encrypt/decrypt must be performed in place */
519 if (out != in || len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN))
520 goto err;
521
522 /*
523 * Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness
524 * Requirements from SP 800-38D". The requirements is for one party to the
525 * communication to fail after 2^64 - 1 keys. We do this on the encrypting
526 * side only.
527 */
528 if (ctx->enc && ++ctx->tls_enc_records == 0) {
529 ERR_raise(ERR_LIB_PROV, PROV_R_TOO_MANY_RECORDS);
530 goto err;
531 }
532
533 /*
534 * Set IV from start of buffer or generate IV and write to start of
535 * buffer.
536 */
537 if (ctx->enc) {
538 if (!getivgen(ctx, out, arg))
539 goto err;
540 } else {
541 if (!setivinv(ctx, out, arg))
542 goto err;
543 }
544
545 /* Fix buffer and length to point to payload */
546 in += EVP_GCM_TLS_EXPLICIT_IV_LEN;
547 out += EVP_GCM_TLS_EXPLICIT_IV_LEN;
548 len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
549
550 tag = ctx->enc ? out + len : (unsigned char *)in + len;
551 if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag,
552 EVP_GCM_TLS_TAG_LEN)) {
553 if (!ctx->enc)
554 OPENSSL_cleanse(out, len);
555 goto err;
556 }
557 if (ctx->enc)
558 plen = len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
559 else
560 plen = len;
561
562 rv = 1;
563 err:
564 ctx->iv_state = IV_STATE_FINISHED;
565 ctx->tls_aad_len = UNINITIALISED_SIZET;
566 *padlen = plen;
567 return rv;
568 }
569