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-rw-r--r--lib/isc/base64.c270
1 files changed, 270 insertions, 0 deletions
diff --git a/lib/isc/base64.c b/lib/isc/base64.c
new file mode 100644
index 0000000..958ef4f
--- /dev/null
+++ b/lib/isc/base64.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <stdbool.h>
+
+#include <isc/base64.h>
+#include <isc/buffer.h>
+#include <isc/lex.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#define RETERR(x) \
+ do { \
+ isc_result_t _r = (x); \
+ if (_r != ISC_R_SUCCESS) \
+ return ((_r)); \
+ } while (0)
+
+/*@{*/
+/*!
+ * These static functions are also present in lib/dns/rdata.c. I'm not
+ * sure where they should go. -- bwelling
+ */
+static isc_result_t
+str_totext(const char *source, isc_buffer_t *target);
+
+static isc_result_t
+mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length);
+
+static const char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvw"
+ "xyz0123456789+/=";
+/*@}*/
+
+isc_result_t
+isc_base64_totext(isc_region_t *source, int wordlength, const char *wordbreak,
+ isc_buffer_t *target) {
+ char buf[5];
+ unsigned int loops = 0;
+
+ if (wordlength < 4) {
+ wordlength = 4;
+ }
+
+ memset(buf, 0, sizeof(buf));
+ while (source->length > 2) {
+ buf[0] = base64[(source->base[0] >> 2) & 0x3f];
+ buf[1] = base64[((source->base[0] << 4) & 0x30) |
+ ((source->base[1] >> 4) & 0x0f)];
+ buf[2] = base64[((source->base[1] << 2) & 0x3c) |
+ ((source->base[2] >> 6) & 0x03)];
+ buf[3] = base64[source->base[2] & 0x3f];
+ RETERR(str_totext(buf, target));
+ isc_region_consume(source, 3);
+
+ loops++;
+ if (source->length != 0 && (int)((loops + 1) * 4) >= wordlength)
+ {
+ loops = 0;
+ RETERR(str_totext(wordbreak, target));
+ }
+ }
+ if (source->length == 2) {
+ buf[0] = base64[(source->base[0] >> 2) & 0x3f];
+ buf[1] = base64[((source->base[0] << 4) & 0x30) |
+ ((source->base[1] >> 4) & 0x0f)];
+ buf[2] = base64[((source->base[1] << 2) & 0x3c)];
+ buf[3] = '=';
+ RETERR(str_totext(buf, target));
+ isc_region_consume(source, 2);
+ } else if (source->length == 1) {
+ buf[0] = base64[(source->base[0] >> 2) & 0x3f];
+ buf[1] = base64[((source->base[0] << 4) & 0x30)];
+ buf[2] = buf[3] = '=';
+ RETERR(str_totext(buf, target));
+ isc_region_consume(source, 1);
+ }
+ return (ISC_R_SUCCESS);
+}
+
+/*%
+ * State of a base64 decoding process in progress.
+ */
+typedef struct {
+ int length; /*%< Desired length of binary data or -1 */
+ isc_buffer_t *target; /*%< Buffer for resulting binary data */
+ int digits; /*%< Number of buffered base64 digits */
+ bool seen_end; /*%< True if "=" end marker seen */
+ int val[4];
+} base64_decode_ctx_t;
+
+static void
+base64_decode_init(base64_decode_ctx_t *ctx, int length, isc_buffer_t *target) {
+ ctx->digits = 0;
+ ctx->seen_end = false;
+ ctx->length = length;
+ ctx->target = target;
+}
+
+static isc_result_t
+base64_decode_char(base64_decode_ctx_t *ctx, int c) {
+ const char *s;
+
+ if (ctx->seen_end) {
+ return (ISC_R_BADBASE64);
+ }
+ if ((s = strchr(base64, c)) == NULL) {
+ return (ISC_R_BADBASE64);
+ }
+ ctx->val[ctx->digits++] = (int)(s - base64);
+ if (ctx->digits == 4) {
+ int n;
+ unsigned char buf[3];
+ if (ctx->val[0] == 64 || ctx->val[1] == 64) {
+ return (ISC_R_BADBASE64);
+ }
+ if (ctx->val[2] == 64 && ctx->val[3] != 64) {
+ return (ISC_R_BADBASE64);
+ }
+ /*
+ * Check that bits that should be zero are.
+ */
+ if (ctx->val[2] == 64 && (ctx->val[1] & 0xf) != 0) {
+ return (ISC_R_BADBASE64);
+ }
+ /*
+ * We don't need to test for ctx->val[2] != 64 as
+ * the bottom two bits of 64 are zero.
+ */
+ if (ctx->val[3] == 64 && (ctx->val[2] & 0x3) != 0) {
+ return (ISC_R_BADBASE64);
+ }
+ n = (ctx->val[2] == 64) ? 1 : (ctx->val[3] == 64) ? 2 : 3;
+ if (n != 3) {
+ ctx->seen_end = true;
+ if (ctx->val[2] == 64) {
+ ctx->val[2] = 0;
+ }
+ if (ctx->val[3] == 64) {
+ ctx->val[3] = 0;
+ }
+ }
+ buf[0] = (ctx->val[0] << 2) | (ctx->val[1] >> 4);
+ buf[1] = (ctx->val[1] << 4) | (ctx->val[2] >> 2);
+ buf[2] = (ctx->val[2] << 6) | (ctx->val[3]);
+ RETERR(mem_tobuffer(ctx->target, buf, n));
+ if (ctx->length >= 0) {
+ if (n > ctx->length) {
+ return (ISC_R_BADBASE64);
+ } else {
+ ctx->length -= n;
+ }
+ }
+ ctx->digits = 0;
+ }
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+base64_decode_finish(base64_decode_ctx_t *ctx) {
+ if (ctx->length > 0) {
+ return (ISC_R_UNEXPECTEDEND);
+ }
+ if (ctx->digits != 0) {
+ return (ISC_R_BADBASE64);
+ }
+ return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_base64_tobuffer(isc_lex_t *lexer, isc_buffer_t *target, int length) {
+ unsigned int before, after;
+ base64_decode_ctx_t ctx;
+ isc_textregion_t *tr;
+ isc_token_t token;
+ bool eol;
+
+ REQUIRE(length >= -2);
+
+ base64_decode_init(&ctx, length, target);
+
+ before = isc_buffer_usedlength(target);
+ while (!ctx.seen_end && (ctx.length != 0)) {
+ unsigned int i;
+
+ if (length > 0) {
+ eol = false;
+ } else {
+ eol = true;
+ }
+ RETERR(isc_lex_getmastertoken(lexer, &token,
+ isc_tokentype_string, eol));
+ if (token.type != isc_tokentype_string) {
+ break;
+ }
+ tr = &token.value.as_textregion;
+ for (i = 0; i < tr->length; i++) {
+ RETERR(base64_decode_char(&ctx, tr->base[i]));
+ }
+ }
+ after = isc_buffer_usedlength(target);
+ if (ctx.length < 0 && !ctx.seen_end) {
+ isc_lex_ungettoken(lexer, &token);
+ }
+ RETERR(base64_decode_finish(&ctx));
+ if (length == -2 && before == after) {
+ return (ISC_R_UNEXPECTEDEND);
+ }
+ return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_base64_decodestring(const char *cstr, isc_buffer_t *target) {
+ base64_decode_ctx_t ctx;
+
+ base64_decode_init(&ctx, -1, target);
+ for (;;) {
+ int c = *cstr++;
+ if (c == '\0') {
+ break;
+ }
+ if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+ continue;
+ }
+ RETERR(base64_decode_char(&ctx, c));
+ }
+ RETERR(base64_decode_finish(&ctx));
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+str_totext(const char *source, isc_buffer_t *target) {
+ unsigned int l;
+ isc_region_t region;
+
+ isc_buffer_availableregion(target, &region);
+ l = strlen(source);
+
+ if (l > region.length) {
+ return (ISC_R_NOSPACE);
+ }
+
+ memmove(region.base, source, l);
+ isc_buffer_add(target, l);
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+mem_tobuffer(isc_buffer_t *target, void *base, unsigned int length) {
+ isc_region_t tr;
+
+ isc_buffer_availableregion(target, &tr);
+ if (length > tr.length) {
+ return (ISC_R_NOSPACE);
+ }
+ memmove(tr.base, base, length);
+ isc_buffer_add(target, length);
+ return (ISC_R_SUCCESS);
+}
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