Do not require /dev/urandom emulation in Javascript any more.

src/libsodium/Makefile.am

@@ -1,6 +1,12 @@
 lib_LTLIBRARIES = \
 	libsodium.la
 
+if !EMSCRIPTEN
+libsodium_la_SOURCES += \
+	randombytes/salsa20/randombytes_salsa20_random.c \
+	randombytes/sysrandom/randombytes_sysrandom.c
+endif
+
 libsodium_la_SOURCES = \
 	crypto_aead/chacha20poly1305/sodium/aead_chacha20poly1305.c \
 	crypto_auth/crypto_auth.c \
@@ -149,8 +155,6 @@ libsodium_la_SOURCES = \
 	crypto_verify/64/ref/api.h \
 	crypto_verify/64/ref/verify_64.c \
 	randombytes/randombytes.c \
-	randombytes/salsa20/randombytes_salsa20_random.c \
-	randombytes/sysrandom/randombytes_sysrandom.c \
 	sodium/core.c \
 	sodium/runtime.c \
 	sodium/utils.c \

src/libsodium/randombytes/randombytes.c

@@ -1,4 +1,8 @@
 
+#ifdef __EMSCRIPTEN__
+# include <emscripten.h>
+#endif
+
 #include <sys/types.h>
 
 #include <assert.h>
@@ -8,8 +12,12 @@
 #include "randombytes.h"
 #include "randombytes_sysrandom.h"
 
+#ifdef __EMSCRIPTEN__
+static const randombytes_implementation *implementation = NULL;
+#else
 static const randombytes_implementation *implementation =
     &randombytes_sysrandom_implementation;
+#endif
 
 int
 randombytes_set_implementation(randombytes_implementation *impl)
@@ -22,39 +30,105 @@ randombytes_set_implementation(randombytes_implementation *impl)
 const char *
 randombytes_implementation_name(void)
 {
+#ifdef __EMSCRIPTEN__
+    return "js";
+#else
     return implementation->implementation_name();
+#endif
 }
 
 uint32_t
 randombytes_random(void)
 {
+#ifdef __EMSCRIPTEN__
+    return EM_ASM_INT_V({
+        return Module.getRandomValue();
+    });
+#else
     return implementation->random();
+#endif
 }
 
 void
 randombytes_stir(void)
 {
+#ifdef __EMSCRIPTEN__
+    EM_ASM({
+        if (Module.getRandomValue === undefined) {
+            try {
+                var randomValuesStandard = function() {
+                    var buf = new Uint16Array(1);
+                    window.crypto.getRandomValues(buf);
+                    return buf[0] >>> 0;
+                };
+                randomValuesStandard();
+                Module.getRandomValue = randomValuesStandard;
+            } catch (e) {
+                try {
+                    var crypto = require('crypto');
+                    var randomValueIOJS = function() {
+                        var buf = crypto.randomBytes(2);
+                        return (buf[0] << 8 | buf[1]) >>> 0;
+                    };
+                    randomValueIOJS();
+                    Module.getRandomValue = randomValueIOJS;
+                } catch (e) {
+                    throw 'No secure random number generator found';
+                }
+            }
+        }
+    });
+#else
     implementation->stir();
+#endif
 }
 
 uint32_t
 randombytes_uniform(const uint32_t upper_bound)
 {
+#ifdef __EMSCRIPTEN__
+    uint32_t min;
+    uint32_t r;
+
+    if (upper_bound < 2) {
+        return 0;
+    }
+    min = (uint32_t) (-upper_bound % upper_bound);
+    do {
+        r = randombytes_random();
+    } while (r < min);
+
+    return r % upper_bound;
+#else
     return implementation->uniform(upper_bound);
+#endif
 }
 
 void
 randombytes_buf(void * const buf, const size_t size)
 {
+#ifdef __EMSCRIPTEN__
+    unsigned char *p = buf;
+    size_t         i;
+
+    for (i = (size_t) 0U; i < size; i++) {
+        p[i] = (unsigned char) randombytes_random();
+    }
+#else
     if (size > (size_t) 0U) {
         implementation->buf(buf, size);
     }
+#endif
 }
 
 int
 randombytes_close(void)
 {
+#ifdef __EMSCRIPTEN__
+    return 0;
+#else
     return implementation->close();
+#endif
 }
 
 void

src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c

@@ -326,12 +326,10 @@ randombytes_salsa20_random_uniform(const uint32_t upper_bound)
         return 0;
     }
     min = (uint32_t) (-upper_bound % upper_bound);
-    for (;;) {
+    do {
         r = randombytes_salsa20_random();
-        if (r >= min) {
-            break;
-        }
-    } /* LCOV_EXCL_LINE */
+    } while (r < min); /* LCOV_EXCL_LINE */
+
     return r % upper_bound;
 }
 

src/libsodium/randombytes/sysrandom/randombytes_sysrandom.c

@@ -241,10 +241,8 @@ randombytes_sysrandom_uniform(const uint32_t upper_bound)
     min = (uint32_t) (-upper_bound % upper_bound);
     for (;;) {
         r = randombytes_sysrandom();
-        if (r >= min) {
-            break;
-        }
-    } /* LCOV_EXCL_LINE */
+    } while (r < min); /* LCOV_EXCL_LINE */
+
     return r % upper_bound;
 }
 

test/default/pre.js.inc

@@ -6,34 +6,7 @@ try {
 }
 Module['preRun'] = Module['preRun'] || [];
 Module['preRun'].push(function(){
-    var randombyte = null;
-    try {
-        function randombyte_standard() {
-            var buf = new Int8Array(1);            
-            window.crypto.getRandomValues(buf);
-            return buf[0];
-        }
-        randombyte_standard();
-        randombyte = randombyte_standard;
-    } catch (e) {
-        try {
-            var crypto = require('crypto');
-            function randombyte_node() {
-                return crypto.randomBytes(1)[0];
-            }
-            randombyte_node();
-            randombyte = randombyte_node;
-        } catch(e) {
-            throw 'No secure random number generator found';
-        }
-    }
     FS.init();
     FS.mkdir('/test-data');
     FS.mount(NODEFS,  { root: '.' }, '/test-data');
-    FS.analyzePath('/dev/random').exists && FS.unlink('/dev/random');
-    FS.analyzePath('/dev/urandom') && FS.unlink('/dev/urandom');
-    var devFolder = FS.findObject('/dev') ||
-        Module['FS_createFolder']('/', 'dev', true, true);
-    Module['FS_createDevice'](devFolder, 'random', randombyte);
-    Module['FS_createDevice'](devFolder, 'urandom', randombyte);
 });

test/default/randombytes.c

@@ -29,8 +29,11 @@ static int randombytes_tests(void)
 {
     unsigned int i;
 
-    assert(strcmp(randombytes_implementation_name(), "sysrandom") == 0);
-
+#ifdef __EMSCRIPTEN__
+    assert(strcmp(randombytes_implementation_name(), "sysrandom"));
+#else
+    assert(strcmp(randombytes_implementation_name(), "js"));
+#endif
     randombytes(x, 1U);
     randombytes_close();
 
@@ -47,8 +50,10 @@ static int randombytes_tests(void)
     }
     assert(randombytes_uniform(1U) == 0U);
     randombytes_close();
+#ifndef __EMSCRIPTEN__
     randombytes_set_implementation(&randombytes_salsa20_implementation);
     assert(strcmp(randombytes_implementation_name(), "salsa20") == 0);
+#endif
     randombytes_stir();
     for (i = 0; i < 256; ++i) {
         freq[i] = 0;