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-rw-r--r--src/tls/tls_prng_dev.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/src/tls/tls_prng_dev.c b/src/tls/tls_prng_dev.c
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+++ b/src/tls/tls_prng_dev.c
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+/*++
+/* NAME
+/* tls_prng_dev 3
+/* SUMMARY
+/* seed OpenSSL PRNG from entropy device
+/* SYNOPSIS
+/* #include <tls_prng_src.h>
+/*
+/* TLS_PRNG_SRC *tls_prng_dev_open(name, timeout)
+/* const char *name;
+/* int timeout;
+/*
+/* ssize_t tls_prng_dev_read(dev, length)
+/* TLS_PRNG_SRC *dev;
+/* size_t length;
+/*
+/* int tls_prng_dev_close(dev)
+/* TLS_PRNG_SRC *dev;
+/* DESCRIPTION
+/* tls_prng_dev_open() opens the specified entropy device
+/* and returns a handle that should be used with all subsequent
+/* access.
+/*
+/* tls_prng_dev_read() reads the requested number of bytes from
+/* the entropy device and updates the OpenSSL PRNG.
+/*
+/* tls_prng_dev_close() closes the specified entropy device
+/* and releases memory that was allocated for the handle.
+/*
+/* Arguments:
+/* .IP name
+/* The pathname of the entropy device.
+/* .IP length
+/* The number of bytes to read from the entropy device.
+/* Request lengths will be truncated at 255 bytes.
+/* .IP timeout
+/* Time limit on individual I/O operations.
+/* DIAGNOSTICS
+/* tls_prng_dev_open() returns a null pointer on error.
+/*
+/* tls_prng_dev_read() returns -1 on error, the number
+/* of bytes received on success.
+/*
+/* tls_prng_dev_close() returns -1 on error, 0 on success.
+/*
+/* In all cases the errno variable indicates the type of error.
+/* LICENSE
+/* .ad
+/* .fi
+/* The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/* Wietse Venema
+/* IBM T.J. Watson Research
+/* P.O. Box 704
+/* Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+
+#ifndef UCHAR_MAX
+#define UCHAR_MAX 0xff
+#endif
+
+/* OpenSSL library. */
+
+#ifdef USE_TLS
+#include <openssl/rand.h> /* For the PRNG */
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <connect.h>
+#include <iostuff.h>
+
+/* TLS library. */
+
+#include <tls_prng.h>
+
+/* tls_prng_dev_open - open entropy device */
+
+TLS_PRNG_SRC *tls_prng_dev_open(const char *name, int timeout)
+{
+ const char *myname = "tls_prng_dev_open";
+ TLS_PRNG_SRC *dev;
+ int fd;
+
+ if ((fd = open(name, O_RDONLY, 0)) < 0) {
+ if (msg_verbose)
+ msg_info("%s: cannot open entropy device %s: %m", myname, name);
+ return (0);
+ } else {
+ dev = (TLS_PRNG_SRC *) mymalloc(sizeof(*dev));
+ dev->fd = fd;
+ dev->name = mystrdup(name);
+ dev->timeout = timeout;
+ if (msg_verbose)
+ msg_info("%s: opened entropy device %s", myname, name);
+ return (dev);
+ }
+}
+
+/* tls_prng_dev_read - update internal PRNG from device */
+
+ssize_t tls_prng_dev_read(TLS_PRNG_SRC *dev, size_t len)
+{
+ const char *myname = "tls_prng_dev_read";
+ unsigned char buffer[UCHAR_MAX];
+ ssize_t count;
+ size_t rand_bytes;
+
+ if (len <= 0)
+ msg_panic("%s: bad read length: %ld", myname, (long) len);
+
+ if (len > sizeof(buffer))
+ rand_bytes = sizeof(buffer);
+ else
+ rand_bytes = len;
+ errno = 0;
+ count = timed_read(dev->fd, buffer, rand_bytes, dev->timeout, (void *) 0);
+ if (count > 0) {
+ if (msg_verbose)
+ msg_info("%s: read %ld bytes from entropy device %s",
+ myname, (long) count, dev->name);
+ RAND_seed(buffer, count);
+ } else {
+ if (msg_verbose)
+ msg_info("%s: cannot read %ld bytes from entropy device %s: %m",
+ myname, (long) rand_bytes, dev->name);
+ }
+ return (count);
+}
+
+/* tls_prng_dev_close - disconnect from EGD server */
+
+int tls_prng_dev_close(TLS_PRNG_SRC *dev)
+{
+ const char *myname = "tls_prng_dev_close";
+ int err;
+
+ if (msg_verbose)
+ msg_info("%s: close entropy device %s", myname, dev->name);
+ err = close(dev->fd);
+ myfree(dev->name);
+ myfree((void *) dev);
+ return (err);
+}
+
+#endif