acl/lib_tls/tls/tls_prng_exch.c
2014-11-19 00:25:21 +08:00

145 lines
4.2 KiB
C

/*++
* NAME
* tls_prng_exch 3
* SUMMARY
* maintain PRNG exchange file
* SYNOPSIS
* #include <tls_prng_src.h>
*
* TLS_PRNG_SRC *tls_prng_exch_open(name, timeout)
* const char *name;
* int timeout;
*
* void tls_prng_exch_update(fh, length)
* TLS_PRNG_SRC *fh;
* size_t length;
*
* void tls_prng_exch_close(fh)
* TLS_PRNG_SRC *fh;
* DESCRIPTION
* tls_prng_exch_open() opens the specified PRNG exchange file
* and returns a handle that should be used with all subsequent
* access.
*
* tls_prng_exch_update() reads the requested number of bytes
* from the PRNG exchange file, updates the OpenSSL PRNG, and
* writes the requested number of bytes to the exchange file.
* The file is locked for exclusive access.
*
* tls_prng_exch_close() closes the specified PRNG exchange
* file and releases memory that was allocated for the handle.
*
* Arguments:
* .IP name
* The name of the PRNG exchange file.
* .IP length
* The number of bytes to read from/write to the entropy file.
* .IP timeout
* Time limit on individual I/O operations.
* DIAGNOSTICS
* All errors are fatal.
* 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
*--*/
#include "StdAfx.h"
#include <fcntl.h>
#ifdef ACL_UNIX
#include <unistd.h>
#endif
#include <limits.h>
/* OpenSSL library. */
#ifdef USE_TLS
#include <openssl/rand.h> /* For the PRNG */
/* TLS library. */
#include "tls_prng.h"
/* Application specific. */
#define TLS_PRNG_EXCH_SIZE 1024 /* XXX Why not configurable? */
/* tls_prng_exch_open - open PRNG exchange file */
TLS_PRNG_SRC *tls_prng_exch_open(const char *name)
{
const char *myname = "tls_prng_exch_open";
TLS_PRNG_SRC *eh;
ACL_FILE_HANDLE fd;
if ((fd = acl_file_open(name, O_RDWR | O_CREAT, 0600)) < 0)
acl_msg_fatal("%s: cannot open PRNG exchange file %s: %s",
myname, name, acl_last_serror());
eh = (TLS_PRNG_SRC *) acl_mymalloc(sizeof(*eh));
eh->fd.file = fd;
eh->name = acl_mystrdup(name);
eh->timeout = 0;
if (acl_msg_verbose)
acl_msg_info("%s: opened PRNG exchange file %s", myname, name);
return (eh);
}
/* tls_prng_exch_update - update PRNG exchange file */
void tls_prng_exch_update(TLS_PRNG_SRC *eh)
{
const char *myname = "tls_prng_exch_update";
unsigned char buffer[TLS_PRNG_EXCH_SIZE];
ssize_t count;
/*
* Update the PRNG exchange file. Since other processes may have added
* entropy, we use a read-stir-write cycle.
*/
if (acl_myflock(eh->fd.file, ACL_INTERNAL_LOCK, ACL_FLOCK_OP_EXCLUSIVE) != 0)
acl_msg_fatal("%s: cannot lock PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if (acl_lseek(eh->fd.file, 0, SEEK_SET) < 0)
acl_msg_fatal("%s: cannot seek PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if ((count = acl_file_read(eh->fd.file, buffer, sizeof(buffer), 0, NULL, NULL)) < 0)
acl_msg_fatal("%s: cannot read PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if (count > 0)
RAND_seed(buffer, count);
RAND_bytes(buffer, sizeof(buffer));
if (acl_lseek(eh->fd.file, 0, SEEK_SET) < 0)
acl_msg_fatal("%s: cannot seek PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if (acl_file_write(eh->fd.file, buffer, sizeof(buffer), 0, NULL, NULL) != sizeof(buffer))
acl_msg_fatal("%s: cannot write PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if (acl_myflock(eh->fd.file, ACL_INTERNAL_LOCK, ACL_FLOCK_OP_NONE) != 0)
acl_msg_fatal("%s: cannot unlock PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
}
/* tls_prng_exch_close - close PRNG exchange file */
void tls_prng_exch_close(TLS_PRNG_SRC *eh)
{
const char *myname = "tls_prng_exch_close";
if (acl_file_close(eh->fd.file) < 0)
acl_msg_fatal("%s: close PRNG exchange file %s: %s",
myname, eh->name, acl_last_serror());
if (acl_msg_verbose)
acl_msg_info("%s: closed PRNG exchange file %s", myname, eh->name);
acl_myfree(eh->name);
acl_myfree(eh);
}
#endif