Refactor asn1_decoder functions into a class.
Test: mmma bootable/recovery Test: recovery_unit_test passes. Test: recovery_component_test passes. Change-Id: If0bf25993158eaebeedff55ba4f4dd0f6e5f937d
This commit is contained in:
Tao Bao
+111
-144
@@ -14,178 +14,145 @@
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* limitations under the License.
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*/
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#include <malloc.h>
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#include <stdint.h>
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#include <string.h>
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#include "asn1_decoder.h"
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#include <stdint.h>
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typedef struct asn1_context {
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size_t length;
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const uint8_t* p;
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int app_type;
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} asn1_context_t;
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static const int kMaskConstructed = 0xE0;
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static const int kMaskTag = 0x7F;
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static const int kMaskAppType = 0x1F;
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static const int kTagOctetString = 0x04;
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static const int kTagOid = 0x06;
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static const int kTagSequence = 0x30;
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static const int kTagSet = 0x31;
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static const int kTagConstructed = 0xA0;
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asn1_context_t* asn1_context_new(const uint8_t* buffer, size_t length) {
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asn1_context_t* ctx = (asn1_context_t*) calloc(1, sizeof(asn1_context_t));
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if (ctx == NULL) {
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return NULL;
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}
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ctx->p = buffer;
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ctx->length = length;
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return ctx;
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int asn1_context::peek_byte() const {
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if (length_ <= 0) {
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return -1;
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}
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return *p_;
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}
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void asn1_context_free(asn1_context_t* ctx) {
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free(ctx);
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int asn1_context::get_byte() {
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if (length_ <= 0) {
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return -1;
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}
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int byte = *p_;
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p_++;
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length_--;
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return byte;
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}
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static inline int peek_byte(asn1_context_t* ctx) {
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if (ctx->length <= 0) {
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return -1;
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}
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return *ctx->p;
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bool asn1_context::skip_bytes(size_t num_skip) {
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if (length_ < num_skip) {
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return false;
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}
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p_ += num_skip;
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length_ -= num_skip;
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return true;
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}
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static inline int get_byte(asn1_context_t* ctx) {
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if (ctx->length <= 0) {
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return -1;
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}
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int byte = *ctx->p;
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ctx->p++;
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ctx->length--;
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return byte;
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}
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static inline bool skip_bytes(asn1_context_t* ctx, size_t num_skip) {
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if (ctx->length < num_skip) {
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return false;
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}
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ctx->p += num_skip;
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ctx->length -= num_skip;
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bool asn1_context::decode_length(size_t* out_len) {
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int num_octets = get_byte();
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if (num_octets == -1) {
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return false;
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}
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if ((num_octets & 0x80) == 0x00) {
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*out_len = num_octets;
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return true;
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}
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static bool decode_length(asn1_context_t* ctx, size_t* out_len) {
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int num_octets = get_byte(ctx);
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if (num_octets == -1) {
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return false;
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}
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num_octets &= kMaskTag;
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if (static_cast<size_t>(num_octets) >= sizeof(size_t)) {
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return false;
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}
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size_t length = 0;
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for (int i = 0; i < num_octets; ++i) {
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int byte = get_byte();
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if (byte == -1) {
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return false;
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}
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if ((num_octets & 0x80) == 0x00) {
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*out_len = num_octets;
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return 1;
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}
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num_octets &= kMaskTag;
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if ((size_t)num_octets >= sizeof(size_t)) {
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return false;
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}
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size_t length = 0;
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for (int i = 0; i < num_octets; ++i) {
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int byte = get_byte(ctx);
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if (byte == -1) {
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return false;
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}
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length <<= 8;
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length += byte;
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}
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*out_len = length;
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return true;
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length <<= 8;
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length += byte;
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}
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*out_len = length;
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return true;
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}
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/**
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* Returns the constructed type and advances the pointer. E.g. A0 -> 0
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*/
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asn1_context_t* asn1_constructed_get(asn1_context_t* ctx) {
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int type = get_byte(ctx);
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if (type == -1 || (type & kMaskConstructed) != kTagConstructed) {
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return NULL;
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}
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asn1_context* asn1_context::asn1_constructed_get() {
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int type = get_byte();
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if (type == -1 || (type & kMaskConstructed) != kTagConstructed) {
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return nullptr;
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}
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size_t length;
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if (!decode_length(&length) || length > length_) {
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return nullptr;
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}
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asn1_context* app_ctx = new asn1_context(p_, length);
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app_ctx->app_type_ = type & kMaskAppType;
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return app_ctx;
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}
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bool asn1_context::asn1_constructed_skip_all() {
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int byte = peek_byte();
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while (byte != -1 && (byte & kMaskConstructed) == kTagConstructed) {
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skip_bytes(1);
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size_t length;
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if (!decode_length(ctx, &length) || length > ctx->length) {
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return NULL;
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if (!decode_length(&length) || !skip_bytes(length)) {
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return false;
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}
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asn1_context_t* app_ctx = asn1_context_new(ctx->p, length);
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app_ctx->app_type = type & kMaskAppType;
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return app_ctx;
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byte = peek_byte();
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}
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return byte != -1;
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}
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bool asn1_constructed_skip_all(asn1_context_t* ctx) {
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int byte = peek_byte(ctx);
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while (byte != -1 && (byte & kMaskConstructed) == kTagConstructed) {
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skip_bytes(ctx, 1);
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size_t length;
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if (!decode_length(ctx, &length) || !skip_bytes(ctx, length)) {
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return false;
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}
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byte = peek_byte(ctx);
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}
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return byte != -1;
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int asn1_context::asn1_constructed_type() const {
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return app_type_;
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}
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int asn1_constructed_type(asn1_context_t* ctx) {
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return ctx->app_type;
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asn1_context* asn1_context::asn1_sequence_get() {
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if ((get_byte() & kMaskTag) != kTagSequence) {
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return nullptr;
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}
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size_t length;
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if (!decode_length(&length) || length > length_) {
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return nullptr;
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}
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return new asn1_context(p_, length);
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}
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asn1_context_t* asn1_sequence_get(asn1_context_t* ctx) {
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if ((get_byte(ctx) & kMaskTag) != kTagSequence) {
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return NULL;
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}
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size_t length;
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if (!decode_length(ctx, &length) || length > ctx->length) {
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return NULL;
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}
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return asn1_context_new(ctx->p, length);
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asn1_context* asn1_context::asn1_set_get() {
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if ((get_byte() & kMaskTag) != kTagSet) {
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return nullptr;
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}
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size_t length;
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if (!decode_length(&length) || length > length_) {
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return nullptr;
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}
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return new asn1_context(p_, length);
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}
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asn1_context_t* asn1_set_get(asn1_context_t* ctx) {
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if ((get_byte(ctx) & kMaskTag) != kTagSet) {
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return NULL;
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}
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size_t length;
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if (!decode_length(ctx, &length) || length > ctx->length) {
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return NULL;
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}
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return asn1_context_new(ctx->p, length);
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bool asn1_context::asn1_sequence_next() {
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size_t length;
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if (get_byte() == -1 || !decode_length(&length) || !skip_bytes(length)) {
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return false;
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}
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return true;
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}
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bool asn1_sequence_next(asn1_context_t* ctx) {
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size_t length;
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if (get_byte(ctx) == -1 || !decode_length(ctx, &length) || !skip_bytes(ctx, length)) {
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return false;
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}
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return true;
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bool asn1_context::asn1_oid_get(const uint8_t** oid, size_t* length) {
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if (get_byte() != kTagOid) {
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return false;
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}
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if (!decode_length(length) || *length == 0 || *length > length_) {
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return false;
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}
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*oid = p_;
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return true;
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}
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bool asn1_oid_get(asn1_context_t* ctx, const uint8_t** oid, size_t* length) {
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if (get_byte(ctx) != kTagOid) {
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return false;
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}
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if (!decode_length(ctx, length) || *length == 0 || *length > ctx->length) {
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return false;
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}
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*oid = ctx->p;
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return true;
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}
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bool asn1_octet_string_get(asn1_context_t* ctx, const uint8_t** octet_string, size_t* length) {
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if (get_byte(ctx) != kTagOctetString) {
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return false;
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}
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if (!decode_length(ctx, length) || *length == 0 || *length > ctx->length) {
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return false;
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}
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*octet_string = ctx->p;
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return true;
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bool asn1_context::asn1_octet_string_get(const uint8_t** octet_string, size_t* length) {
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if (get_byte() != kTagOctetString) {
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return false;
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}
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if (!decode_length(length) || *length == 0 || *length > length_) {
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return false;
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}
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*octet_string = p_;
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return true;
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}
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