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LibCrypto: Make a better ASN.1 parser

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And use it to parse RSA keys.
As a bonus, this one shouldn't be reading out of bounds or messing with
the stack (as much) anymore.
This commit is contained in:
AnotherTest 2021-02-14 14:50:42 +03:30 • committed by Andreas Kling
parent 4d40864b9d
commit 3fe7ac0924
13 changed files with 893 additions and 624 deletions
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72
Userland/Libraries/LibCrypto/ASN1/PEM.cpp Normal file
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/*
* Copyright (c) 2021, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Base64.h>
#include <AK/GenericLexer.h>
#include <LibCrypto/ASN1/PEM.h>
namespace Crypto {
ByteBuffer decode_pem(ReadonlyBytes data)
{
GenericLexer lexer { data };
ByteBuffer decoded;
// FIXME: Parse multiple.
enum {
PreStartData,
Started,
Ended,
} state { PreStartData };
while (!lexer.is_eof()) {
switch (state) {
case PreStartData:
if (lexer.consume_specific("-----BEGIN"))
state = Started;
lexer.consume_line();
break;
case Started: {
if (lexer.consume_specific("-----END")) {
state = Ended;
lexer.consume_line();
break;
}
auto b64decoded = decode_base64(lexer.consume_line().trim_whitespace(TrimMode::Right));
decoded.append(b64decoded.data(), b64decoded.size());
break;
}
case Ended:
lexer.consume_all();
break;
default:
ASSERT_NOT_REACHED();
}
}
return decoded;
}
}