2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
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
13 #include "internal/cryptlib_int.h"
14 #include "internal/err.h"
15 #include "internal/err_int.h"
16 #include <openssl/err.h>
17 #include <openssl/crypto.h>
18 #include <openssl/buffer.h>
19 #include <openssl/bio.h>
20 #include <openssl/opensslconf.h>
21 #include "internal/thread_once.h"
22 #include "internal/ctype.h"
23 #include "internal/constant_time_locl.h"
27 static int err_load_strings(const ERR_STRING_DATA *str);
29 static void ERR_STATE_free(ERR_STATE *s);
30 #ifndef OPENSSL_NO_ERR
31 static ERR_STRING_DATA ERR_str_libraries[] = {
32 {ERR_PACK(ERR_LIB_NONE, 0, 0), "unknown library"},
33 {ERR_PACK(ERR_LIB_SYS, 0, 0), "system library"},
34 {ERR_PACK(ERR_LIB_BN, 0, 0), "bignum routines"},
35 {ERR_PACK(ERR_LIB_RSA, 0, 0), "rsa routines"},
36 {ERR_PACK(ERR_LIB_DH, 0, 0), "Diffie-Hellman routines"},
37 {ERR_PACK(ERR_LIB_EVP, 0, 0), "digital envelope routines"},
38 {ERR_PACK(ERR_LIB_BUF, 0, 0), "memory buffer routines"},
39 {ERR_PACK(ERR_LIB_OBJ, 0, 0), "object identifier routines"},
40 {ERR_PACK(ERR_LIB_PEM, 0, 0), "PEM routines"},
41 {ERR_PACK(ERR_LIB_DSA, 0, 0), "dsa routines"},
42 {ERR_PACK(ERR_LIB_X509, 0, 0), "x509 certificate routines"},
43 {ERR_PACK(ERR_LIB_ASN1, 0, 0), "asn1 encoding routines"},
44 {ERR_PACK(ERR_LIB_CONF, 0, 0), "configuration file routines"},
45 {ERR_PACK(ERR_LIB_CRYPTO, 0, 0), "common libcrypto routines"},
46 {ERR_PACK(ERR_LIB_EC, 0, 0), "elliptic curve routines"},
47 {ERR_PACK(ERR_LIB_ECDSA, 0, 0), "ECDSA routines"},
48 {ERR_PACK(ERR_LIB_ECDH, 0, 0), "ECDH routines"},
49 {ERR_PACK(ERR_LIB_SSL, 0, 0), "SSL routines"},
50 {ERR_PACK(ERR_LIB_BIO, 0, 0), "BIO routines"},
51 {ERR_PACK(ERR_LIB_PKCS7, 0, 0), "PKCS7 routines"},
52 {ERR_PACK(ERR_LIB_X509V3, 0, 0), "X509 V3 routines"},
53 {ERR_PACK(ERR_LIB_PKCS12, 0, 0), "PKCS12 routines"},
54 {ERR_PACK(ERR_LIB_RAND, 0, 0), "random number generator"},
55 {ERR_PACK(ERR_LIB_DSO, 0, 0), "DSO support routines"},
56 {ERR_PACK(ERR_LIB_TS, 0, 0), "time stamp routines"},
57 {ERR_PACK(ERR_LIB_ENGINE, 0, 0), "engine routines"},
58 {ERR_PACK(ERR_LIB_OCSP, 0, 0), "OCSP routines"},
59 {ERR_PACK(ERR_LIB_UI, 0, 0), "UI routines"},
60 {ERR_PACK(ERR_LIB_FIPS, 0, 0), "FIPS routines"},
61 {ERR_PACK(ERR_LIB_CMS, 0, 0), "CMS routines"},
62 {ERR_PACK(ERR_LIB_CRMF, 0, 0), "CRMF routines"},
63 {ERR_PACK(ERR_LIB_CMP, 0, 0), "CMP routines"},
64 {ERR_PACK(ERR_LIB_HMAC, 0, 0), "HMAC routines"},
65 {ERR_PACK(ERR_LIB_CT, 0, 0), "CT routines"},
66 {ERR_PACK(ERR_LIB_ASYNC, 0, 0), "ASYNC routines"},
67 {ERR_PACK(ERR_LIB_KDF, 0, 0), "KDF routines"},
68 {ERR_PACK(ERR_LIB_OSSL_STORE, 0, 0), "STORE routines"},
69 {ERR_PACK(ERR_LIB_SM2, 0, 0), "SM2 routines"},
70 {ERR_PACK(ERR_LIB_ESS, 0, 0), "ESS routines"},
71 {ERR_PACK(ERR_LIB_PROV, 0, 0), "Provider routines"},
75 static ERR_STRING_DATA ERR_str_reasons[] = {
76 {ERR_R_SYS_LIB, "system lib"},
77 {ERR_R_BN_LIB, "BN lib"},
78 {ERR_R_RSA_LIB, "RSA lib"},
79 {ERR_R_DH_LIB, "DH lib"},
80 {ERR_R_EVP_LIB, "EVP lib"},
81 {ERR_R_BUF_LIB, "BUF lib"},
82 {ERR_R_OBJ_LIB, "OBJ lib"},
83 {ERR_R_PEM_LIB, "PEM lib"},
84 {ERR_R_DSA_LIB, "DSA lib"},
85 {ERR_R_X509_LIB, "X509 lib"},
86 {ERR_R_ASN1_LIB, "ASN1 lib"},
87 {ERR_R_EC_LIB, "EC lib"},
88 {ERR_R_BIO_LIB, "BIO lib"},
89 {ERR_R_PKCS7_LIB, "PKCS7 lib"},
90 {ERR_R_X509V3_LIB, "X509V3 lib"},
91 {ERR_R_ENGINE_LIB, "ENGINE lib"},
92 {ERR_R_UI_LIB, "UI lib"},
93 {ERR_R_OSSL_STORE_LIB, "STORE lib"},
94 {ERR_R_ECDSA_LIB, "ECDSA lib"},
96 {ERR_R_NESTED_ASN1_ERROR, "nested asn1 error"},
97 {ERR_R_MISSING_ASN1_EOS, "missing asn1 eos"},
99 {ERR_R_FATAL, "fatal"},
100 {ERR_R_MALLOC_FAILURE, "malloc failure"},
101 {ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED,
102 "called a function you should not call"},
103 {ERR_R_PASSED_NULL_PARAMETER, "passed a null parameter"},
104 {ERR_R_INTERNAL_ERROR, "internal error"},
105 {ERR_R_DISABLED, "called a function that was disabled at compile-time"},
106 {ERR_R_INIT_FAIL, "init fail"},
107 {ERR_R_OPERATION_FAIL, "operation fail"},
113 static CRYPTO_ONCE err_init = CRYPTO_ONCE_STATIC_INIT;
114 static int set_err_thread_local;
115 static CRYPTO_THREAD_LOCAL err_thread_local;
117 static CRYPTO_ONCE err_string_init = CRYPTO_ONCE_STATIC_INIT;
118 static CRYPTO_RWLOCK *err_string_lock;
120 static ERR_STRING_DATA *int_err_get_item(const ERR_STRING_DATA *);
126 static LHASH_OF(ERR_STRING_DATA) *int_error_hash = NULL;
127 static int int_err_library_number = ERR_LIB_USER;
129 static unsigned long get_error_values(int inc, int top, const char **file,
130 int *line, const char **data,
133 static unsigned long err_string_data_hash(const ERR_STRING_DATA *a)
135 unsigned long ret, l;
138 ret = l ^ ERR_GET_LIB(l);
139 return (ret ^ ret % 19 * 13);
142 static int err_string_data_cmp(const ERR_STRING_DATA *a,
143 const ERR_STRING_DATA *b)
145 if (a->error == b->error)
147 return a->error > b->error ? 1 : -1;
150 static ERR_STRING_DATA *int_err_get_item(const ERR_STRING_DATA *d)
152 ERR_STRING_DATA *p = NULL;
154 CRYPTO_THREAD_read_lock(err_string_lock);
155 p = lh_ERR_STRING_DATA_retrieve(int_error_hash, d);
156 CRYPTO_THREAD_unlock(err_string_lock);
161 #ifndef OPENSSL_NO_ERR
162 /* 2019-05-21: Russian and Ukrainian locales on Linux require more than 6,5 kB */
163 # define SPACE_SYS_STR_REASONS 8 * 1024
164 # define NUM_SYS_STR_REASONS 127
166 static ERR_STRING_DATA SYS_str_reasons[NUM_SYS_STR_REASONS + 1];
168 * SYS_str_reasons is filled with copies of strerror() results at
169 * initialization. 'errno' values up to 127 should cover all usual errors,
170 * others will be displayed numerically by ERR_error_string. It is crucial
171 * that we have something for each reason code that occurs in
172 * ERR_str_reasons, or bogus reason strings will be returned for SYSerr(),
173 * which always gets an errno value and never one of those 'standard' reason
177 static void build_SYS_str_reasons(void)
179 /* OPENSSL_malloc cannot be used here, use static storage instead */
180 static char strerror_pool[SPACE_SYS_STR_REASONS];
181 char *cur = strerror_pool;
185 int saveerrno = get_last_sys_error();
187 CRYPTO_THREAD_write_lock(err_string_lock);
189 CRYPTO_THREAD_unlock(err_string_lock);
193 for (i = 1; i <= NUM_SYS_STR_REASONS; i++) {
194 ERR_STRING_DATA *str = &SYS_str_reasons[i - 1];
196 str->error = ERR_PACK(ERR_LIB_SYS, 0, i);
198 * If we have used up all the space in strerror_pool,
199 * there's no point in calling openssl_strerror_r()
201 if (str->string == NULL && cnt < sizeof(strerror_pool)) {
202 if (openssl_strerror_r(i, cur, sizeof(strerror_pool) - cnt)) {
203 size_t l = strlen(cur);
210 * VMS has an unusual quirk of adding spaces at the end of
211 * some (most? all?) messages. Lets trim them off.
213 while (cur > strerror_pool && ossl_isspace(cur[-1])) {
221 if (str->string == NULL)
222 str->string = "unknown";
226 * Now we still have SYS_str_reasons[NUM_SYS_STR_REASONS] = {0, NULL}, as
227 * required by ERR_load_strings.
232 CRYPTO_THREAD_unlock(err_string_lock);
233 /* openssl_strerror_r could change errno, but we want to preserve it */
234 set_sys_error(saveerrno);
235 err_load_strings(SYS_str_reasons);
239 static void ERR_STATE_free(ERR_STATE *s)
245 for (i = 0; i < ERR_NUM_ERRORS; i++) {
246 err_clear_data(s, i, 1);
251 DEFINE_RUN_ONCE_STATIC(do_err_strings_init)
253 if (!OPENSSL_init_crypto(0, NULL))
255 err_string_lock = CRYPTO_THREAD_lock_new();
256 if (err_string_lock == NULL)
258 int_error_hash = lh_ERR_STRING_DATA_new(err_string_data_hash,
259 err_string_data_cmp);
260 if (int_error_hash == NULL) {
261 CRYPTO_THREAD_lock_free(err_string_lock);
262 err_string_lock = NULL;
268 void err_cleanup(void)
270 if (set_err_thread_local != 0)
271 CRYPTO_THREAD_cleanup_local(&err_thread_local);
272 CRYPTO_THREAD_lock_free(err_string_lock);
273 err_string_lock = NULL;
274 lh_ERR_STRING_DATA_free(int_error_hash);
275 int_error_hash = NULL;
279 * Legacy; pack in the library.
281 static void err_patch(int lib, ERR_STRING_DATA *str)
283 unsigned long plib = ERR_PACK(lib, 0, 0);
285 for (; str->error != 0; str++)
290 * Hash in |str| error strings. Assumes the URN_ONCE was done.
292 static int err_load_strings(const ERR_STRING_DATA *str)
294 CRYPTO_THREAD_write_lock(err_string_lock);
295 for (; str->error; str++)
296 (void)lh_ERR_STRING_DATA_insert(int_error_hash,
297 (ERR_STRING_DATA *)str);
298 CRYPTO_THREAD_unlock(err_string_lock);
302 int ERR_load_ERR_strings(void)
304 #ifndef OPENSSL_NO_ERR
305 if (!RUN_ONCE(&err_string_init, do_err_strings_init))
308 err_load_strings(ERR_str_libraries);
309 err_load_strings(ERR_str_reasons);
310 build_SYS_str_reasons();
315 int ERR_load_strings(int lib, ERR_STRING_DATA *str)
317 if (ERR_load_ERR_strings() == 0)
321 err_load_strings(str);
325 int ERR_load_strings_const(const ERR_STRING_DATA *str)
327 if (ERR_load_ERR_strings() == 0)
329 err_load_strings(str);
333 int ERR_unload_strings(int lib, ERR_STRING_DATA *str)
335 if (!RUN_ONCE(&err_string_init, do_err_strings_init))
338 CRYPTO_THREAD_write_lock(err_string_lock);
340 * We don't need to ERR_PACK the lib, since that was done (to
341 * the table) when it was loaded.
343 for (; str->error; str++)
344 (void)lh_ERR_STRING_DATA_delete(int_error_hash, str);
345 CRYPTO_THREAD_unlock(err_string_lock);
350 void err_free_strings_int(void)
352 if (!RUN_ONCE(&err_string_init, do_err_strings_init))
356 /********************************************************/
358 void ERR_clear_error(void)
363 es = ERR_get_state();
367 for (i = 0; i < ERR_NUM_ERRORS; i++) {
370 es->top = es->bottom = 0;
373 unsigned long ERR_get_error(void)
375 return get_error_values(1, 0, NULL, NULL, NULL, NULL);
378 unsigned long ERR_get_error_line(const char **file, int *line)
380 return get_error_values(1, 0, file, line, NULL, NULL);
383 unsigned long ERR_get_error_line_data(const char **file, int *line,
384 const char **data, int *flags)
386 return get_error_values(1, 0, file, line, data, flags);
389 unsigned long ERR_peek_error(void)
391 return get_error_values(0, 0, NULL, NULL, NULL, NULL);
394 unsigned long ERR_peek_error_line(const char **file, int *line)
396 return get_error_values(0, 0, file, line, NULL, NULL);
399 unsigned long ERR_peek_error_line_data(const char **file, int *line,
400 const char **data, int *flags)
402 return get_error_values(0, 0, file, line, data, flags);
405 unsigned long ERR_peek_last_error(void)
407 return get_error_values(0, 1, NULL, NULL, NULL, NULL);
410 unsigned long ERR_peek_last_error_line(const char **file, int *line)
412 return get_error_values(0, 1, file, line, NULL, NULL);
415 unsigned long ERR_peek_last_error_line_data(const char **file, int *line,
416 const char **data, int *flags)
418 return get_error_values(0, 1, file, line, data, flags);
421 static unsigned long get_error_values(int inc, int top, const char **file,
422 int *line, const char **data,
429 es = ERR_get_state();
443 return ERR_R_INTERNAL_ERROR;
446 while (es->bottom != es->top) {
447 if (es->err_flags[es->top] & ERR_FLAG_CLEAR) {
448 err_clear(es, es->top, 0);
449 es->top = es->top > 0 ? es->top - 1 : ERR_NUM_ERRORS - 1;
452 i = (es->bottom + 1) % ERR_NUM_ERRORS;
453 if (es->err_flags[i] & ERR_FLAG_CLEAR) {
455 err_clear(es, es->bottom, 0);
461 if (es->bottom == es->top)
465 i = es->top; /* last error */
467 i = (es->bottom + 1) % ERR_NUM_ERRORS; /* first error */
469 ret = es->err_buffer[i];
472 es->err_buffer[i] = 0;
475 if (file != NULL && line != NULL) {
476 if (es->err_file[i] == NULL) {
480 *file = es->err_file[i];
481 *line = es->err_line[i];
487 err_clear_data(es, i, 0);
490 if (es->err_data[i] == NULL) {
495 *data = es->err_data[i];
497 *flags = es->err_data_flags[i];
503 void ERR_error_string_n(unsigned long e, char *buf, size_t len)
505 char lsbuf[64], rsbuf[64];
507 unsigned long f = 0, l, r;
513 ls = ERR_lib_error_string(e);
515 BIO_snprintf(lsbuf, sizeof(lsbuf), "lib(%lu)", l);
519 rs = ERR_reason_error_string(e);
520 r = ERR_GET_REASON(e);
522 BIO_snprintf(rsbuf, sizeof(rsbuf), "reason(%lu)", r);
526 BIO_snprintf(buf, len, "error:%08lX:%s:%s:%s", e, ls, "", rs);
527 if (strlen(buf) == len - 1) {
528 /* Didn't fit; use a minimal format. */
529 BIO_snprintf(buf, len, "err:%lx:%lx:%lx:%lx", e, l, f, r);
534 * ERR_error_string_n should be used instead for ret != NULL as
535 * ERR_error_string cannot know how large the buffer is
537 char *ERR_error_string(unsigned long e, char *ret)
539 static char buf[256];
543 ERR_error_string_n(e, ret, (int)sizeof(buf));
547 const char *ERR_lib_error_string(unsigned long e)
549 ERR_STRING_DATA d, *p;
552 if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
557 d.error = ERR_PACK(l, 0, 0);
558 p = int_err_get_item(&d);
559 return ((p == NULL) ? NULL : p->string);
562 const char *ERR_func_error_string(unsigned long e)
564 if (!RUN_ONCE(&err_string_init, do_err_strings_init))
566 return ERR_GET_LIB(e) == ERR_LIB_SYS ? "system library" : NULL;
569 const char *ERR_reason_error_string(unsigned long e)
571 ERR_STRING_DATA d, *p = NULL;
574 if (!RUN_ONCE(&err_string_init, do_err_strings_init)) {
579 r = ERR_GET_REASON(e);
580 d.error = ERR_PACK(l, 0, r);
581 p = int_err_get_item(&d);
583 d.error = ERR_PACK(0, 0, r);
584 p = int_err_get_item(&d);
586 return ((p == NULL) ? NULL : p->string);
589 /* TODO(3.0): arg ignored for now */
590 static void err_delete_thread_state(void *arg)
592 ERR_STATE *state = CRYPTO_THREAD_get_local(&err_thread_local);
596 CRYPTO_THREAD_set_local(&err_thread_local, NULL);
597 ERR_STATE_free(state);
600 #if !OPENSSL_API_1_1_0
601 void ERR_remove_thread_state(void *dummy)
606 #if !OPENSSL_API_1_0_0
607 void ERR_remove_state(unsigned long pid)
612 DEFINE_RUN_ONCE_STATIC(err_do_init)
614 set_err_thread_local = 1;
615 return CRYPTO_THREAD_init_local(&err_thread_local, NULL);
618 ERR_STATE *ERR_get_state(void)
621 int saveerrno = get_last_sys_error();
623 if (!OPENSSL_init_crypto(OPENSSL_INIT_BASE_ONLY, NULL))
626 if (!RUN_ONCE(&err_init, err_do_init))
629 state = CRYPTO_THREAD_get_local(&err_thread_local);
630 if (state == (ERR_STATE*)-1)
634 if (!CRYPTO_THREAD_set_local(&err_thread_local, (ERR_STATE*)-1))
637 if ((state = OPENSSL_zalloc(sizeof(*state))) == NULL) {
638 CRYPTO_THREAD_set_local(&err_thread_local, NULL);
642 if (!ossl_init_thread_start(NULL, NULL, err_delete_thread_state)
643 || !CRYPTO_THREAD_set_local(&err_thread_local, state)) {
644 ERR_STATE_free(state);
645 CRYPTO_THREAD_set_local(&err_thread_local, NULL);
649 /* Ignore failures from these */
650 OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
653 set_sys_error(saveerrno);
658 * err_shelve_state returns the current thread local error state
659 * and freezes the error module until err_unshelve_state is called.
661 int err_shelve_state(void **state)
663 int saveerrno = get_last_sys_error();
666 * Note, at present our only caller is OPENSSL_init_crypto(), indirectly
667 * via ossl_init_load_crypto_nodelete(), by which point the requested
668 * "base" initialization has already been performed, so the below call is a
669 * NOOP, that re-enters OPENSSL_init_crypto() only to quickly return.
671 * If are no other valid callers of this function, the call below can be
672 * removed, avoiding the re-entry into OPENSSL_init_crypto(). If there are
673 * potential uses that are not from inside OPENSSL_init_crypto(), then this
674 * call is needed, but some care is required to make sure that the re-entry
677 if (!OPENSSL_init_crypto(OPENSSL_INIT_BASE_ONLY, NULL))
680 if (!RUN_ONCE(&err_init, err_do_init))
683 *state = CRYPTO_THREAD_get_local(&err_thread_local);
684 if (!CRYPTO_THREAD_set_local(&err_thread_local, (ERR_STATE*)-1))
687 set_sys_error(saveerrno);
692 * err_unshelve_state restores the error state that was returned
693 * by err_shelve_state previously.
695 void err_unshelve_state(void* state)
697 if (state != (void*)-1)
698 CRYPTO_THREAD_set_local(&err_thread_local, (ERR_STATE*)state);
701 int ERR_get_next_error_library(void)
705 if (!RUN_ONCE(&err_string_init, do_err_strings_init))
708 CRYPTO_THREAD_write_lock(err_string_lock);
709 ret = int_err_library_number++;
710 CRYPTO_THREAD_unlock(err_string_lock);
714 static int err_set_error_data_int(char *data, size_t size, int flags,
719 es = ERR_get_state();
723 err_clear_data(es, es->top, deallocate);
724 err_set_data(es, es->top, data, size, flags);
729 void ERR_set_error_data(char *data, int flags)
732 * This function is void so we cannot propagate the error return. Since it
733 * is also in the public API we can't change the return type.
735 * We estimate the size of the data. If it's not flagged as allocated,
736 * then this is safe, and if it is flagged as allocated, then our size
737 * may be smaller than the actual allocation, but that doesn't matter
738 * too much, the buffer will remain untouched or will eventually be
739 * reallocated to a new size.
741 * callers should be advised that this function takes over ownership of
742 * the allocated memory, i.e. they can't count on the pointer to remain
745 err_set_error_data_int(data, strlen(data) + 1, flags, 1);
748 void ERR_add_error_data(int num, ...)
752 ERR_add_error_vdata(num, args);
756 void ERR_add_error_vdata(int num, va_list args)
759 int flags = ERR_TXT_MALLOCED | ERR_TXT_STRING;
763 /* Get the current error data; if an allocated string get it. */
764 es = ERR_get_state();
770 * If err_data is allocated already, re-use the space.
771 * Otherwise, allocate a small new buffer.
773 if ((es->err_data_flags[i] & flags) == flags) {
774 str = es->err_data[i];
775 size = es->err_data_size[i];
778 * To protect the string we just grabbed from tampering by other
779 * functions we may call, or to protect them from freeing a pointer
780 * that may no longer be valid at that point, we clear away the
781 * data pointer and the flags. We will set them again at the end
784 es->err_data[i] = NULL;
785 es->err_data_flags[i] = 0;
786 } else if ((str = OPENSSL_malloc(size = 81)) == NULL) {
793 for (len = 0; --num >= 0; ) {
794 arg = va_arg(args, char *);
802 p = OPENSSL_realloc(str, size + 1);
809 OPENSSL_strlcat(str, arg, (size_t)size + 1);
811 if (!err_set_error_data_int(str, size, flags, 0))
815 int ERR_set_mark(void)
819 es = ERR_get_state();
823 if (es->bottom == es->top)
825 es->err_flags[es->top] |= ERR_FLAG_MARK;
829 int ERR_pop_to_mark(void)
833 es = ERR_get_state();
837 while (es->bottom != es->top
838 && (es->err_flags[es->top] & ERR_FLAG_MARK) == 0) {
839 err_clear(es, es->top, 0);
840 es->top = es->top > 0 ? es->top - 1 : ERR_NUM_ERRORS - 1;
843 if (es->bottom == es->top)
845 es->err_flags[es->top] &= ~ERR_FLAG_MARK;
849 int ERR_clear_last_mark(void)
854 es = ERR_get_state();
859 while (es->bottom != top
860 && (es->err_flags[top] & ERR_FLAG_MARK) == 0) {
861 top = top > 0 ? top - 1 : ERR_NUM_ERRORS - 1;
864 if (es->bottom == top)
866 es->err_flags[top] &= ~ERR_FLAG_MARK;
870 void err_clear_last_constant_time(int clear)
875 es = ERR_get_state();
882 * Flag error as cleared but remove it elsewhere to avoid two errors
883 * accessing the same error stack location, revealing timing information.
885 clear = constant_time_select_int(constant_time_eq_int(clear, 0),
887 es->err_flags[top] |= clear;