xref: /JGit/org.eclipse.jgit.gpg.bc/src/org/eclipse/jgit/gpg/bc/internal/keys/SXprUtils.java (revision bdc48aeac756cc0471618b06d793083e63109ee0)
1 /*
2  * Copyright (c) 2000-2021 The Legion of the Bouncy Castle Inc. (https://www.bouncycastle.org)
3  * <p>
4  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
5  * and associated documentation files (the "Software"), to deal in the Software without restriction,
6  *including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
7  * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
8  * subject to the following conditions:
9  * </p>
10  * <p>
11  * The above copyright notice and this permission notice shall be included in all copies or substantial
12  * portions of the Software.
13  * </p>
14  * <p>
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
16  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
17  * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
20  * DEALINGS IN THE SOFTWARE.
21  * </p>
22  */
23 package org.eclipse.jgit.gpg.bc.internal.keys;
24 
25 // This class is an unmodified copy from Bouncy Castle; needed because it's package-visible only and used by SExprParser.
26 
27 import java.io.IOException;
28 import java.io.InputStream;
29 
30 import org.bouncycastle.bcpg.HashAlgorithmTags;
31 import org.bouncycastle.bcpg.S2K;
32 import org.bouncycastle.util.io.Streams;
33 
34 /**
35  * Utility functions for looking a S-expression keys. This class will move when
36  * it finds a better home!
37  * <p>
38  * Format documented here:
39  * http://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=agent/keyformat.txt;h=42c4b1f06faf1bbe71ffadc2fee0fad6bec91a97;hb=refs/heads/master
40  * </p>
41  */
42 class SXprUtils {
readLength(InputStream in, int ch)43 	private static int readLength(InputStream in, int ch) throws IOException {
44 		int len = ch - '0';
45 
46 		while ((ch = in.read()) >= 0 && ch != ':') {
47 			len = len * 10 + ch - '0';
48 		}
49 
50 		return len;
51 	}
52 
readString(InputStream in, int ch)53 	static String readString(InputStream in, int ch) throws IOException {
54 		int len = readLength(in, ch);
55 
56 		char[] chars = new char[len];
57 
58 		for (int i = 0; i != chars.length; i++) {
59 			chars[i] = (char) in.read();
60 		}
61 
62 		return new String(chars);
63 	}
64 
readBytes(InputStream in, int ch)65 	static byte[] readBytes(InputStream in, int ch) throws IOException {
66 		int len = readLength(in, ch);
67 
68 		byte[] data = new byte[len];
69 
70 		Streams.readFully(in, data);
71 
72 		return data;
73 	}
74 
parseS2K(InputStream in)75 	static S2K parseS2K(InputStream in) throws IOException {
76 		skipOpenParenthesis(in);
77 
78 		// Algorithm is hard-coded to SHA1 below anyway.
79 		readString(in, in.read());
80 		byte[] iv = readBytes(in, in.read());
81 		final long iterationCount = Long.parseLong(readString(in, in.read()));
82 
83 		skipCloseParenthesis(in);
84 
85 		// we have to return the actual iteration count provided.
86 		S2K s2k = new S2K(HashAlgorithmTags.SHA1, iv, (int) iterationCount) {
87 			@Override
88 			public long getIterationCount() {
89 				return iterationCount;
90 			}
91 		};
92 
93 		return s2k;
94 	}
95 
skipOpenParenthesis(InputStream in)96 	static void skipOpenParenthesis(InputStream in) throws IOException {
97 		int ch = in.read();
98 		if (ch != '(') {
99 			throw new IOException(
100 					"unknown character encountered: " + (char) ch); //$NON-NLS-1$
101 		}
102 	}
103 
skipCloseParenthesis(InputStream in)104 	static void skipCloseParenthesis(InputStream in) throws IOException {
105 		int ch = in.read();
106 		if (ch != ')') {
107 			throw new IOException("unknown character encountered"); //$NON-NLS-1$
108 		}
109 	}
110 }
111