/*
* Copyright (C) 2013, 2014 Eric Biggers
*
- * This file is part of wimlib, a library for working with WIM files.
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option) any
+ * later version.
*
- * wimlib is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3 of the License, or (at your option)
- * any later version.
- *
- * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * This file is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
- * You should have received a copy of the GNU General Public License
- * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this file; if not, see http://www.gnu.org/licenses/.
*/
#ifdef __WIN32__
#include "wimlib/reparse.h"
#include "wimlib/textfile.h"
#include "wimlib/xml.h"
+#include "wimlib/wildcard.h"
#include "wimlib/wimboot.h"
struct win32_apply_ctx {
return 0;
}
-/* Returns %true if the path to @dentry matches a pattern in [PrepopulateList]
- * of WimBootCompress.ini. Otherwise returns %false.
- *
- * @dentry must have had its full path calculated. */
+/* Returns %true if the specified absolute path to a file in the WIM image
+ * matches a pattern in [PrepopulateList] of WimBootCompress.ini. Otherwise
+ * returns %false. */
static bool
-in_prepopulate_list(struct wim_dentry *dentry,
+in_prepopulate_list(const wchar_t *path, size_t path_nchars,
const struct win32_apply_ctx *ctx)
{
const struct string_set *pats = ctx->wimboot.prepopulate_pats;
if (!pats || !pats->num_strings)
return false;
- return match_pattern_list(dentry->_full_path,
- wcslen(dentry->_full_path), pats);
+ return match_pattern_list(path, path_nchars, pats);
+}
+
+/* Returns %true if the specified absolute path to a file in the WIM image can
+ * be subject to external backing when extracted. Otherwise returns %false. */
+static bool
+can_externally_back_path(const wchar_t *path, size_t path_nchars,
+ const struct win32_apply_ctx *ctx)
+{
+ if (in_prepopulate_list(path, path_nchars, ctx))
+ return false;
+
+ /* Since we attempt to modify the SYSTEM registry after it's extracted
+ * (see end_wimboot_extraction()), it can't be extracted as externally
+ * backed. This extends to associated files such as SYSTEM.LOG that
+ * also must be writable in order to write to the registry. Normally,
+ * SYSTEM is in [PrepopulateList], and the SYSTEM.* files match patterns
+ * in [ExclusionList] and therefore are not captured in the WIM at all.
+ * However, a WIM that wasn't specifically captured in "WIMBoot mode"
+ * may contain SYSTEM.* files. So to make things "just work", hard-code
+ * the pattern. */
+ if (match_path(path, path_nchars, L"\\Windows\\System32\\config\\SYSTEM*",
+ OS_PREFERRED_PATH_SEPARATOR, false))
+ return false;
+
+ return true;
}
static const wchar_t *
if (ret)
return ret;
- if (in_prepopulate_list(dentry, ctx))
+ if (!can_externally_back_path(dentry->_full_path,
+ wcslen(dentry->_full_path), ctx))
return WIM_BACKING_EXCLUDED;
return 0;
/* Set the security descriptor @desc, of @desc_size bytes, on the file with open
* handle @h. */
static NTSTATUS
-set_security_descriptor(HANDLE h, const void *desc,
+set_security_descriptor(HANDLE h, const void *_desc,
size_t desc_size, struct win32_apply_ctx *ctx)
{
SECURITY_INFORMATION info;
NTSTATUS status;
+ SECURITY_DESCRIPTOR_RELATIVE *desc;
+
+ /*
+ * Ideally, we would just pass in the security descriptor buffer as-is.
+ * But it turns out that Windows can mess up the security descriptor
+ * even when using the low-level NtSetSecurityObject() function:
+ *
+ * - Windows will clear SE_DACL_AUTO_INHERITED if it is set in the
+ * passed buffer. To actually get Windows to set
+ * SE_DACL_AUTO_INHERITED, the application must set the non-persistent
+ * flag SE_DACL_AUTO_INHERIT_REQ. As usual, Microsoft didn't bother
+ * to properly document either of these flags. It's unclear how
+ * important SE_DACL_AUTO_INHERITED actually is, but to be safe we use
+ * the SE_DACL_AUTO_INHERIT_REQ workaround to set it if needed.
+ *
+ * - The above also applies to the equivalent SACL flags,
+ * SE_SACL_AUTO_INHERITED and SE_SACL_AUTO_INHERIT_REQ.
+ *
+ * - If the application says that it's setting
+ * DACL_SECURITY_INFORMATION, then Windows sets SE_DACL_PRESENT in the
+ * resulting security descriptor, even if the security descriptor the
+ * application provided did not have a DACL. This seems to be
+ * unavoidable, since omitting DACL_SECURITY_INFORMATION would cause a
+ * default DACL to remain. Fortunately, this behavior seems harmless,
+ * since the resulting DACL will still be "null" --- but it will be
+ * "the other representation of null".
+ *
+ * - The above also applies to SACL_SECURITY_INFORMATION and
+ * SE_SACL_PRESENT. Again, it's seemingly unavoidable but "harmless"
+ * that Windows changes the representation of a "null SACL".
+ */
+ if (likely(desc_size <= STACK_MAX)) {
+ desc = alloca(desc_size);
+ } else {
+ desc = MALLOC(desc_size);
+ if (!desc)
+ return STATUS_NO_MEMORY;
+ }
+
+ memcpy(desc, _desc, desc_size);
+
+ if (likely(desc_size >= 4)) {
+
+ if (desc->Control & SE_DACL_AUTO_INHERITED)
+ desc->Control |= SE_DACL_AUTO_INHERIT_REQ;
+
+ if (desc->Control & SE_SACL_AUTO_INHERITED)
+ desc->Control |= SE_SACL_AUTO_INHERIT_REQ;
+ }
+
+ /*
+ * More API insanity. We want to set the entire security descriptor
+ * as-is. But all available APIs require specifying the specific parts
+ * of the security descriptor being set. Especially annoying is that
+ * mandatory integrity labels are part of the SACL, but they aren't set
+ * with SACL_SECURITY_INFORMATION. Instead, applications must also
+ * specify LABEL_SECURITY_INFORMATION (Windows Vista, Windows 7) or
+ * BACKUP_SECURITY_INFORMATION (Windows 8). But at least older versions
+ * of Windows don't error out if you provide these newer flags...
+ *
+ * Also, if the process isn't running as Administrator, then it probably
+ * doesn't have SE_RESTORE_PRIVILEGE. In this case, it will always get
+ * the STATUS_PRIVILEGE_NOT_HELD error by trying to set the SACL, even
+ * if the security descriptor it provided did not have a SACL. By
+ * default, in this case we try to recover and set as much of the
+ * security descriptor as possible --- potentially excluding the DACL, and
+ * even the owner, as well as the SACL.
+ */
- /* We really just want to set entire the security descriptor as-is, but
- * all available APIs require specifying the specific parts of the
- * descriptor being set. Start out by requesting all parts be set. If
- * permissions problems are encountered, fall back to omitting some
- * parts (first the SACL, then the DACL, then the owner), unless the
- * WIMLIB_EXTRACT_FLAG_STRICT_ACLS flag has been enabled. */
info = OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION |
- DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION;
-
- /* Prefer NtSetSecurityObject() to SetFileSecurity(). SetFileSecurity()
- * itself necessarily uses NtSetSecurityObject() as the latter is the
- * underlying system call for setting security information, but
- * SetFileSecurity() opens the handle with NtCreateFile() without
- * FILE_OPEN_FILE_BACKUP_INTENT. Hence, access checks are done and due
- * to the Windows security model, even a process running as the
- * Administrator can have access denied. (Of course, this not mentioned
- * in the MS "documentation".) */
+ DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION |
+ LABEL_SECURITY_INFORMATION | BACKUP_SECURITY_INFORMATION;
+
+
+ /*
+ * It's also worth noting that SetFileSecurity() is unusable because it
+ * doesn't request "backup semantics" when it opens the file internally.
+ * NtSetSecurityObject() seems to be the best function to use in backup
+ * applications. (SetSecurityInfo() should also work, but it's harder
+ * to use and must call NtSetSecurityObject() internally anyway.
+ * BackupWrite() is theoretically usable as well, but it's inflexible
+ * and poorly documented.)
+ */
+
retry:
- status = (*func_NtSetSecurityObject)(h, info, (PSECURITY_DESCRIPTOR)desc);
+ status = (*func_NtSetSecurityObject)(h, info, desc);
if (NT_SUCCESS(status))
- return status;
+ goto out_maybe_free_desc;
+
/* Failed to set the requested parts of the security descriptor. If the
* error was permissions-related, try to set fewer parts of the security
* descriptor, unless WIMLIB_EXTRACT_FLAG_STRICT_ACLS is enabled. */
!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_STRICT_ACLS))
{
if (info & SACL_SECURITY_INFORMATION) {
- info &= ~SACL_SECURITY_INFORMATION;
+ info &= ~(SACL_SECURITY_INFORMATION |
+ LABEL_SECURITY_INFORMATION |
+ BACKUP_SECURITY_INFORMATION);
ctx->partial_security_descriptors++;
goto retry;
}
if (!(info & SACL_SECURITY_INFORMATION))
ctx->partial_security_descriptors--;
ctx->no_security_descriptors++;
+
+out_maybe_free_desc:
+ if (unlikely(desc_size > STACK_MAX))
+ FREE(desc);
return status;
}
git://wimlib.net / wimlib / blobdiff