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Posted to commits@apr.apache.org by tr...@apache.org on 2013/10/14 00:56:51 UTC
svn commit: r1531768 - in /apr/apr/trunk: CHANGES shmem/win32/shm.c
Author: trawick
Date: Sun Oct 13 22:56:51 2013
New Revision: 1531768
URL: http://svn.apache.org/r1531768
Log:
Windows: Create named shared memory segments under the "Local"
namespace if the caller is unprivileged, fixing an inability of
unprivileged callers to use apr_shm_create() with named shared
memory segments under recent Windows.
Modified:
apr/apr/trunk/CHANGES
apr/apr/trunk/shmem/win32/shm.c
Modified: apr/apr/trunk/CHANGES
URL: http://svn.apache.org/viewvc/apr/apr/trunk/CHANGES?rev=1531768&r1=1531767&r2=1531768&view=diff
==============================================================================
--- apr/apr/trunk/CHANGES [utf-8] (original)
+++ apr/apr/trunk/CHANGES [utf-8] Sun Oct 13 22:56:51 2013
@@ -1,6 +1,11 @@
-*- coding: utf-8 -*-
Changes for APR 2.0.0
+ *) Windows: Create named shared memory segments under the "Local"
+ namespace if the caller is unprivileged, fixing an inability of
+ unprivileged callers to use apr_shm_create() with named shared
+ memory segments under recent Windows. [Jeff Trawick]
+
*) Add apr_pbase64_encode() and apr_pbase64_decode() to encode to/from
the pool. [Graham Leggett]
Modified: apr/apr/trunk/shmem/win32/shm.c
URL: http://svn.apache.org/viewvc/apr/apr/trunk/shmem/win32/shm.c?rev=1531768&r1=1531767&r2=1531768&view=diff
==============================================================================
--- apr/apr/trunk/shmem/win32/shm.c (original)
+++ apr/apr/trunk/shmem/win32/shm.c Sun Oct 13 22:56:51 2013
@@ -56,6 +56,64 @@ static apr_status_t shm_cleanup(void* sh
return rv;
}
+/* See if the caller is able to create a map in the global namespace by
+ * checking if the SE_CREATE_GLOBAL_NAME privilege is enabled.
+ *
+ * Prior to APR 1.5.0, named shared memory segments were always created
+ * in the global segment. However, with recent versions of Windows this
+ * fails for unprivileged processes. Thus, with older APR, named shared
+ * memory segments can't be created by unprivileged processes on newer
+ * Windows.
+ *
+ * By checking if the caller has the privilege, shm APIs can decide
+ * whether to use the Global or Local namespace.
+ *
+ * If running on an SDK without the required API definitions *OR*
+ * some processing failure occurs trying to check the privilege, fall
+ * back to earlier behavior -- always try to use the Global namespace.
+ */
+#ifdef SE_CREATE_GLOBAL_NAME
+static int can_create_global_maps(void)
+{
+ BOOL ok, has_priv;
+ LUID priv_id;
+ PRIVILEGE_SET privs;
+ HANDLE hToken;
+
+ ok = OpenThreadToken(GetCurrentThread(), TOKEN_QUERY, TRUE, &hToken);
+ if (!ok && GetLastError() == ERROR_NO_TOKEN) {
+ /* no thread-specific access token, so try to get process access token
+ */
+ ok = OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken);
+ }
+
+ if (ok) {
+ ok = LookupPrivilegeValue(NULL, SE_CREATE_GLOBAL_NAME, &priv_id);
+ }
+
+ if (ok) {
+ privs.PrivilegeCount = 1;
+ privs.Control = PRIVILEGE_SET_ALL_NECESSARY;
+ privs.Privilege[0].Luid = priv_id;
+ privs.Privilege[0].Attributes = SE_PRIVILEGE_ENABLED;
+ ok = PrivilegeCheck(hToken, &privs, &has_priv);
+ }
+
+ if (ok && !has_priv) {
+ return 0;
+ }
+ else {
+ return 1;
+ }
+}
+#else /* SE_CREATE_GLOBAL_NAME */
+/* SDK definitions missing */
+static int can_create_global_maps(void)
+{
+ return 1;
+}
+#endif /* SE_CREATE_GLOBAL_NAME */
+
APR_DECLARE(apr_status_t) apr_shm_create(apr_shm_t **m,
apr_size_t reqsize,
const char *file,
@@ -112,9 +170,9 @@ APR_DECLARE(apr_status_t) apr_shm_create
/* res_name_from_filename turns file into a pseudo-name
* without slashes or backslashes, and prepends the \global
- * prefix on Win2K and later
+ * or \local prefix on Win2K and later
*/
- mapkey = res_name_from_filename(file, 1, pool);
+ mapkey = res_name_from_filename(file, can_create_global_maps(), pool);
}
#if APR_HAS_UNICODE_FS
@@ -183,24 +241,20 @@ APR_DECLARE(apr_status_t) apr_shm_remove
return apr_file_remove(filename, pool);
}
-APR_DECLARE(apr_status_t) apr_shm_attach(apr_shm_t **m,
- const char *file,
- apr_pool_t *pool)
+static apr_status_t shm_attach_internal(apr_shm_t **m,
+ const char *file,
+ apr_pool_t *pool,
+ int global)
{
HANDLE hMap;
void *mapkey;
void *base;
- if (!file) {
- return APR_EINVAL;
- }
- else {
- /* res_name_from_filename turns file into a pseudo-name
- * without slashes or backslashes, and prepends the \global
- * prefix on Win2K and later
- */
- mapkey = res_name_from_filename(file, 1, pool);
- }
+ /* res_name_from_filename turns file into a pseudo-name
+ * without slashes or backslashes, and prepends the \global
+ * or local prefix on Win2K and later
+ */
+ mapkey = res_name_from_filename(file, global, pool);
#if APR_HAS_UNICODE_FS
IF_WIN_OS_IS_UNICODE
@@ -264,6 +318,36 @@ APR_DECLARE(apr_status_t) apr_shm_attach
return APR_SUCCESS;
}
+APR_DECLARE(apr_status_t) apr_shm_attach(apr_shm_t **m,
+ const char *file,
+ apr_pool_t *pool)
+{
+ apr_status_t rv;
+ int can_create_global = can_create_global_maps();
+ int try_global_local[3] = {1, /* first try to find shm under global namespace */
+ 0, /* next try to find it under local namespace */
+ -1}; /* nothing more to try */
+ int cur;
+
+ if (!file) {
+ return APR_EINVAL;
+ }
+
+ if (!can_create_global) { /* unprivileged process */
+ try_global_local[0] = 0; /* search local before global */
+ try_global_local[1] = 1;
+ }
+
+ for (cur = 0; try_global_local[cur] != -1; cur++) {
+ rv = shm_attach_internal(m, file, pool, try_global_local[cur]);
+ if (!APR_STATUS_IS_ENOENT(rv)) {
+ break;
+ }
+ }
+
+ return rv;
+}
+
APR_DECLARE(apr_status_t) apr_shm_detach(apr_shm_t *m)
{
apr_status_t rv = shm_cleanup(m);