1 files changed, 84 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/unix_urandom.c b/security/nss/lib/freebl/unix_urandom.c
new file mode 100644
index 0000000000..73006cdbb4
--- /dev/null
+++ b/security/nss/lib/freebl/unix_urandom.c
@@ -0,0 +1,84 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include "secerr.h"
+#include "secrng.h"
+#include "prprf.h"
+
+/* syscall getentropy() is limited to retrieving 256 bytes */
+#define GETENTROPY_MAX_BYTES 256
+
+void
+RNG_SystemInfoForRNG(void)
+{
+    PRUint8 bytes[SYSTEM_RNG_SEED_COUNT];
+    size_t numBytes = RNG_SystemRNG(bytes, SYSTEM_RNG_SEED_COUNT);
+    if (!numBytes) {
+        /* error is set */
+        return;
+    }
+    RNG_RandomUpdate(bytes, numBytes);
+    PORT_Memset(bytes, 0, sizeof bytes);
+}
+
+size_t
+RNG_SystemRNG(void *dest, size_t maxLen)
+{
+    int fd;
+    int bytes;
+    size_t fileBytes = 0;
+    unsigned char *buffer = dest;
+
+#if defined(__OpenBSD__) || (defined(__FreeBSD__) && __FreeBSD_version >= 1200000) || (defined(LINUX) && defined(__GLIBC__) && ((__GLIBC__ > 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 25))))
+    int result;
+
+    while (fileBytes < maxLen) {
+        size_t getBytes = maxLen - fileBytes;
+        if (getBytes > GETENTROPY_MAX_BYTES) {
+            getBytes = GETENTROPY_MAX_BYTES;
+        }
+        result = getentropy(buffer, getBytes);
+        if (result == 0) { /* success */
+            fileBytes += getBytes;
+            buffer += getBytes;
+        } else {
+            break;
+        }
+    }
+    if (fileBytes == maxLen) { /* success */
+        return maxLen;
+    }
+    /* If we failed with an error other than ENOSYS, it means the destination
+     * buffer is not writeable. We don't need to try writing to it again. */
+    if (errno != ENOSYS) {
+        PORT_SetError(SEC_ERROR_NEED_RANDOM);
+        return 0;
+    }
+    /* ENOSYS means the kernel doesn't support getentropy()/getrandom().
+     * Reset the number of bytes to get and fall back to /dev/urandom. */
+    fileBytes = 0;
+#endif
+    fd = open("/dev/urandom", O_RDONLY);
+    if (fd < 0) {
+        PORT_SetError(SEC_ERROR_NEED_RANDOM);
+        return 0;
+    }
+    while (fileBytes < maxLen) {
+        bytes = read(fd, buffer, maxLen - fileBytes);
+        if (bytes <= 0) {
+            break;
+        }
+        fileBytes += bytes;
+        buffer += bytes;
+    }
+    (void)close(fd);
+    if (fileBytes != maxLen) {
+        PORT_SetError(SEC_ERROR_NEED_RANDOM);
+        return 0;
+    }
+    return fileBytes;
+}