From aadb9e2e90925a187877241e50110e4ce7ea80a1 Mon Sep 17 00:00:00 2001
From: Benjamin Barenblat <bbaren@mit.edu>
Date: Sat, 14 Mar 2015 19:47:09 -0400
Subject: Imported Upstream version 1.3

---
 secure_memory_unix.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 secure_memory_unix.c

(limited to 'secure_memory_unix.c')

diff --git a/secure_memory_unix.c b/secure_memory_unix.c
new file mode 100644
index 0000000..1ccf855
--- /dev/null
+++ b/secure_memory_unix.c
@@ -0,0 +1,135 @@
+/*
+  secure_memory_unix.c - secure memory implementation for UNIX systems
+  (c) 2004-2005 Zeljko Vrba <zvrba@globalnet.hr>
+
+  Permission is hereby granted, free of charge, to any person obtaining
+  a copy of this software and associated documentation files (the
+  "Software"), to deal in the Software without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of the Software, and to
+  permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include "secure_random.h"
+#include "secure_memory.h"
+#include "exceptions.h"
+
+static char rcsid[] = "$Id: secure_memory_unix.c 1 2005-11-13 20:23:40Z zvrba $";
+
+#ifndef MAP_ANON
+#define MAP_ANON	MAP_ANONYMOUS
+#endif
+
+struct secure_memory *G_secure_memory;
+unsigned int G_secure_memory_size;
+static long G_pagesize;
+
+static int allocate_secure_memory(void)
+{
+	int retval = 1;
+
+	if((G_pagesize = sysconf(_SC_PAGESIZE)) < 0) {
+		perror("sysconf");
+		Throw(system_call_failed_exception);
+	}
+
+	G_secure_memory_size = 16*G_pagesize;
+	G_secure_memory = mmap(NULL, G_secure_memory_size, PROT_READ | PROT_WRITE,
+			MAP_ANON | MAP_PRIVATE, -1, 0);
+	if(G_secure_memory == MAP_FAILED) {
+		perror("mmap");
+		Throw(out_of_memory_exception);
+	}
+
+	/* This is to guarantee segfault on buffer overrun. */
+	if(mprotect((char*)G_secure_memory + 15*G_pagesize, G_pagesize,
+				PROT_NONE) < 0) {
+		perror("mprotect");
+		Throw(system_call_failed_exception);
+	}
+
+#ifdef DISABLE_MLOCKALL
+	/*
+	 * On some OSes (most notably some Linux 2.6 kernels versions), some
+	 * libraries try to allocate too much space and then crash (because
+	 * the allocation would exceed the maximum allowed number of locked
+	 * pages). Which results in a crash.
+	 *
+	 * However, this gives lower security since the stack pages are not
+	 * locked in memory.
+	 */
+	if(mlock(G_secure_memory, G_secure_memory_size) < 0) {
+		perror("mlock");
+		retval = 0;
+	}
+#else
+	if(mlockall(MCL_FUTURE) < 0) {
+		perror("mlockall");
+		retval = 0;
+	}
+#endif
+
+	return retval;
+}
+
+static void drop_privileges(void)
+{
+	if(seteuid(getuid()) < 0) {
+		perror("seteuid");
+		Throw(system_call_failed_exception);
+	}
+}
+
+static int disable_core_file(void)
+{
+	int retval = 1;
+	struct rlimit rlim = { 0, 0 };
+
+	if(setrlimit(RLIMIT_CORE, &rlim) < 0) {
+		perror("setrlimit");
+		retval = 0;
+	}
+
+	return retval;
+}
+
+int secure_memory_init(void)
+{
+	int success;
+
+	success  = allocate_secure_memory();
+	drop_privileges();
+	success &= disable_core_file();
+
+	if(!success) 
+		fprintf(stderr, "WARNING: using insecure memory.\n");
+
+	return success;
+}
+
+void secure_memory_destroy(void)
+{
+	printf("INFO: zeroing memory.\n");
+	memset(G_secure_memory, 0, G_secure_memory_size - G_pagesize);
+}
+
-- 
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