{"id":10008112,"date":"2023-08-18T10:43:49","date_gmt":"2023-08-18T02:43:49","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008112"},"modified":"2023-08-18T10:43:49","modified_gmt":"2023-08-18T02:43:49","slug":"%e8%81%8a%e8%81%8ajava%e7%9a%84java-security-egd","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008112","title":{"rendered":"\u804a\u804ajava\u7684java.security.egd"},"content":{"rendered":"

\u5e8f<\/h2>\n

\u672c\u6587\u4e3b\u8981\u7814\u7a76\u4e00\u4e0bjava\u7684java.security.egd<\/p>\n

SunEntries<\/h2>\n

\/Library\/Java\/JavaVirtualMachines\/temurin-8.jdk\/Contents\/Home\/src.zip!\/sun\/security\/provider\/SunEntries.java<\/p>\n

    \/\/ name of the *System* property, takes precedence over PROP_RNDSOURCE\n    private final static String PROP_EGD = "java.security.egd";\n    \/\/ name of the *Security* property\n    private final static String PROP_RNDSOURCE = "securerandom.source";\n\n    final static String URL_DEV_RANDOM = "file:\/dev\/random";\n    final static String URL_DEV_URANDOM = "file:\/dev\/urandom";\n\n    private static final String seedSource;\n\n    static {\n        seedSource = AccessController.doPrivileged(\n                new PrivilegedAction<String>() {\n\n            @Override\n            public String run() {\n                String egdSource = System.getProperty(PROP_EGD, "");\n                if (egdSource.length() != 0) {\n                    return egdSource;\n                }\n                egdSource = Security.getProperty(PROP_RNDSOURCE);\n                if (egdSource == null) {\n                    return "";\n                }\n                return egdSource;\n            }\n        });\n    }<\/code><\/pre>\n
\u8fd9\u91cc\u4f18\u5148\u8bfb\u53d6java.security.egd<\/code>\uff0c\u5982\u679c\u6ca1\u6709\u8bbe\u7f6e\u5219\u8bfb\u53d6$JAVA_HOME\/jre\/lib\/security\/java.security<\/code>\u6587\u4ef6\u4e2d\u7684securerandom.source<\/code>\u914d\u7f6e\uff0c\u9ed8\u8ba4\u503c\u4e3afile:\/dev\/random<\/code><\/p><\/blockquote>\n
SeedGenerator<\/h2>\n
\/Library\/Java\/JavaVirtualMachines\/temurin-8.jdk\/Contents\/Home\/src.zip!\/sun\/security\/provider\/SeedGenerator.java<\/p>\n
    \/\/ Static initializer to hook in selected or best performing generator\n    static {\n        String egdSource = SunEntries.getSeedSource();\n\n        \/*\n         * Try the URL specifying the source (e.g. file:\/dev\/random)\n         *\n         * The URLs "file:\/dev\/random" or "file:\/dev\/urandom" are used to\n         * indicate the SeedGenerator should use OS support, if available.\n         *\n         * On Windows, this causes the MS CryptoAPI seeder to be used.\n         *\n         * On Solaris\/Linux\/MacOS, this is identical to using\n         * URLSeedGenerator to read from \/dev\/[u]random\n         *\/\n        if (egdSource.equals(SunEntries.URL_DEV_RANDOM) ||\n                egdSource.equals(SunEntries.URL_DEV_URANDOM)) {\n            try {\n                instance = new NativeSeedGenerator(egdSource);\n                if (debug != null) {\n                    debug.println(\n                        "Using operating system seed generator" + egdSource);\n                }\n            } catch (IOException e) {\n                if (debug != null) {\n                    debug.println("Failed to use operating system seed "\n                                  + "generator: " + e.toString());\n                }\n            }\n        } else if (egdSource.length() != 0) {\n            try {\n                instance = new URLSeedGenerator(egdSource);\n                if (debug != null) {\n                    debug.println("Using URL seed generator reading from "\n                                  + egdSource);\n                }\n            } catch (IOException e) {\n                if (debug != null) {\n                    debug.println("Failed to create seed generator with "\n                                  + egdSource + ": " + e.toString());\n                }\n            }\n        }\n\n        \/\/ Fall back to ThreadedSeedGenerator\n        if (instance == null) {\n            if (debug != null) {\n                debug.println("Using default threaded seed generator");\n            }\n            instance = new ThreadedSeedGenerator();\n        }\n    }<\/code><\/pre>\n
\u5982\u679c\u662ffile:\/dev\/random<\/code>\u53cafile:\/dev\/urandom<\/code>\u5219\u8d70NativeSeedGenerator\uff0c\u4e0d\u662f\u5219\u8d70URLSeedGenerator\uff0c\u4e3a\u7a7a\u5219\u8d70ThreadedSeedGenerator<\/p><\/blockquote>\n
NativeSeedGenerator<\/h2>\n
\/**\n * Native seed generator for Unix systems. Inherit everything from\n * URLSeedGenerator.\n *\n *\/\nclass NativeSeedGenerator extends SeedGenerator.URLSeedGenerator {\n\n    NativeSeedGenerator(String seedFile) throws IOException {\n        super(seedFile);\n    }\n\n}<\/code><\/pre>\n
NativeSeedGenerator\u7ee7\u627f\u4e86URLSeedGenerator<\/p><\/blockquote>\n
SecureRandomSpi<\/h2>\n
NativePRNG<\/h3>\n
\/Library\/Java\/JavaVirtualMachines\/temurin-8.jdk\/Contents\/Home\/src.zip!\/sun\/security\/provider\/NativePRNG.java<\/p>\n
public final class NativePRNG extends SecureRandomSpi {\n\n    private static final long serialVersionUID = -6599091113397072932L;\n\n    private static final Debug debug = Debug.getInstance("provider");\n\n    \/\/ name of the pure random file (also used for setSeed())\n    private static final String NAME_RANDOM = "\/dev\/random";\n    \/\/ name of the pseudo random file\n    private static final String NAME_URANDOM = "\/dev\/urandom";\n\n    \/\/ which kind of RandomIO object are we creating?\n    private enum Variant {\n        MIXED, BLOCKING, NONBLOCKING\n    }\n\n    \/\/ singleton instance or null if not available\n    private static final RandomIO INSTANCE = initIO(Variant.MIXED);\n\n    \/**\n     * Get the System egd source (if defined).  We only allow "file:"\n     * URLs for now. If there is a egd value, parse it.\n     *\n     * @return the URL or null if not available.\n     *\/\n    private static URL getEgdUrl() {\n        \/\/ This will return "" if nothing was set.\n        String egdSource = SunEntries.getSeedSource();\n        URL egdUrl;\n\n        if (egdSource.length() != 0) {\n            if (debug != null) {\n                debug.println("NativePRNG egdUrl: " + egdSource);\n            }\n            try {\n                egdUrl = new URL(egdSource);\n                if (!egdUrl.getProtocol().equalsIgnoreCase("file")) {\n                    return null;\n                }\n            } catch (MalformedURLException e) {\n                return null;\n            }\n        } else {\n            egdUrl = null;\n        }\n\n        return egdUrl;\n    }\n\n    \/\/......\n}    <\/code><\/pre>\n
NativePRNG\u7684getEgdUrl\u5219\u901a\u8fc7egdSource\u6765\u6784\u5efaURL<\/p><\/blockquote>\n
\u5c0f\u7ed3<\/h2>\n