Tighten behavior of _rs_allocate on Windows.

For Windows, we are simply using calloc, which has two annoyances:
the memory has more permissions than needed by default, and it comes
from the process heap, which looks like a memory leak since this memory
is rightfully never freed.

This switches _rs_alloc on Windows to use VirtualAlloc, which restricts the
memory to READ|WRITE and keeps the memory out of the process heap.

ok deraadt@

diff --git a/lib/libcrypto/arc4random/arc4random_win.h b/lib/libcrypto/arc4random/arc4random_win.h
index 48a1bda..deec8a1 100644 (file)
--- a/lib/libcrypto/arc4random/arc4random_win.h
+++ b/lib/libcrypto/arc4random/arc4random_win.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: arc4random_win.h,v 1.5 2015/01/15 06:57:18 deraadt Exp $      */
+/*     $OpenBSD: arc4random_win.h,v 1.6 2016/06/30 12:17:29 bcook Exp $        */
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -52,13 +52,16 @@ _getentropy_fail(void)
 static inline int
 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
 {
-       *rsp = calloc(1, sizeof(**rsp));
+       *rsp = VirtualAlloc(NULL, sizeof(**rsp),
+           MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
        if (*rsp == NULL)
                return (-1);
 
-       *rsxp = calloc(1, sizeof(**rsxp));
+       *rsxp = VirtualAlloc(NULL, sizeof(**rsxp),
+           MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
        if (*rsxp == NULL) {
-               free(*rsp);
+               VirtualFree(*rsp, 0, MEM_RELEASE);
+               *rsp = NULL;
                return (-1);
        }
        return (0);

diff --git a/lib/libcrypto/crypto/arc4random_win.h b/lib/libcrypto/crypto/arc4random_win.h
index 48a1bda..deec8a1 100644 (file)
--- a/lib/libcrypto/crypto/arc4random_win.h
+++ b/lib/libcrypto/crypto/arc4random_win.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: arc4random_win.h,v 1.5 2015/01/15 06:57:18 deraadt Exp $      */
+/*     $OpenBSD: arc4random_win.h,v 1.6 2016/06/30 12:17:29 bcook Exp $        */
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -52,13 +52,16 @@ _getentropy_fail(void)
 static inline int
 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
 {
-       *rsp = calloc(1, sizeof(**rsp));
+       *rsp = VirtualAlloc(NULL, sizeof(**rsp),
+           MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
        if (*rsp == NULL)
                return (-1);
 
-       *rsxp = calloc(1, sizeof(**rsxp));
+       *rsxp = VirtualAlloc(NULL, sizeof(**rsxp),
+           MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
        if (*rsxp == NULL) {
-               free(*rsp);
+               VirtualFree(*rsp, 0, MEM_RELEASE);
+               *rsp = NULL;
                return (-1);
        }
        return (0);