]> wimlib.net Git - wimlib/blobdiff - src/win32_apply.c
win32_{apply,capture}.c: workaround for SACL_SECURITY_INFORMATION quirk
[wimlib] / src / win32_apply.c
index 21ddfd2f0cb06e6181808ce8bab4d9ed21d15d53..39e7d405c509d5cc5171bd3f194e9b2615d50b0e 100644 (file)
@@ -953,20 +953,22 @@ set_short_name(HANDLE h, const struct wim_dentry *dentry,
         * with the former case being removing the existing short name if
         * present, rather than setting one.
         *
-        * FileName seemingly does not, however, need to be null-terminated in
-        * any case.
+        * The null terminator is seemingly optional, but to be safe we include
+        * space for it and zero all unused space.
         */
 
        size_t bufsize = offsetof(FILE_NAME_INFORMATION, FileName) +
-                        max(dentry->short_name_nbytes, 2 * sizeof(wchar_t));
+                        max(dentry->short_name_nbytes, sizeof(wchar_t)) +
+                        sizeof(wchar_t);
        u8 buf[bufsize] _aligned_attribute(8);
        FILE_NAME_INFORMATION *info = (FILE_NAME_INFORMATION *)buf;
        NTSTATUS status;
 
+       memset(buf, 0, bufsize);
+
        info->FileNameLength = dentry->short_name_nbytes;
        memcpy(info->FileName, dentry->short_name, dentry->short_name_nbytes);
 
-
 retry:
        status = (*func_NtSetInformationFile)(h, &ctx->iosb, info, bufsize,
                                              FileShortNameInformation);
@@ -1198,16 +1200,15 @@ create_directories(struct list_head *dentry_list,
 
                /* If the root dentry is being extracted, it was already done so
                 * in prepare_target().  */
-               if (dentry_is_root(dentry))
-                       continue;
-
-               ret = create_directory(dentry, ctx);
-               if (ret)
-                       return ret;
+               if (!dentry_is_root(dentry)) {
+                       ret = create_directory(dentry, ctx);
+                       if (ret)
+                               return ret;
 
-               ret = create_any_empty_ads(dentry, ctx);
-               if (ret)
-                       return ret;
+                       ret = create_any_empty_ads(dentry, ctx);
+                       if (ret)
+                               return ret;
+               }
 
                ret = report_file_created(&ctx->common);
                if (ret)
@@ -1458,11 +1459,11 @@ create_nondirectories(struct list_head *dentry_list, struct win32_apply_ctx *ctx
                if (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)
                        continue;
                /* Call create_nondirectory() only once per inode  */
-               if (dentry != inode_first_extraction_dentry(inode))
-                       continue;
-               ret = create_nondirectory(inode, ctx);
-               if (ret)
-                       return ret;
+               if (dentry == inode_first_extraction_dentry(inode)) {
+                       ret = create_nondirectory(inode, ctx);
+                       if (ret)
+                               return ret;
+               }
                ret = report_file_created(&ctx->common);
                if (ret)
                        return ret;
@@ -2008,33 +2009,100 @@ end_extract_stream(struct wim_lookup_table_entry *stream, int status, void *_ctx
 /* 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.  */
@@ -2043,7 +2111,9 @@ retry:
            !(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;
                }
@@ -2065,6 +2135,10 @@ 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;
 }
 
@@ -2233,12 +2307,25 @@ do_warnings(const struct win32_apply_ctx *ctx)
        }
 }
 
+static uint64_t
+count_dentries(const struct list_head *dentry_list)
+{
+       const struct list_head *cur;
+       uint64_t count = 0;
+
+       list_for_each(cur, dentry_list)
+               count++;
+
+       return count;
+}
+
 /* Extract files from a WIM image to a directory on Windows  */
 static int
 win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
 {
        int ret;
        struct win32_apply_ctx *ctx = (struct win32_apply_ctx *)_ctx;
+       uint64_t dentry_count;
 
        ret = prepare_target(dentry_list, ctx);
        if (ret)
@@ -2250,7 +2337,11 @@ win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
                        goto out;
        }
 
-       reset_file_progress(&ctx->common);
+       dentry_count = count_dentries(dentry_list);
+
+       ret = start_file_structure_phase(&ctx->common, dentry_count);
+       if (ret)
+               goto out;
 
        ret = create_directories(dentry_list, ctx);
        if (ret)
@@ -2260,6 +2351,10 @@ win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
        if (ret)
                goto out;
 
+       ret = end_file_structure_phase(&ctx->common);
+       if (ret)
+               goto out;
+
        struct read_stream_list_callbacks cbs = {
                .begin_stream      = begin_extract_stream,
                .begin_stream_ctx  = ctx,
@@ -2272,12 +2367,18 @@ win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
        if (ret)
                goto out;
 
-       reset_file_progress(&ctx->common);
+       ret = start_file_metadata_phase(&ctx->common, dentry_count);
+       if (ret)
+               goto out;
 
        ret = apply_metadata(dentry_list, ctx);
        if (ret)
                goto out;
 
+       ret = end_file_metadata_phase(&ctx->common);
+       if (ret)
+               goto out;
+
        if (unlikely(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT)) {
                ret = end_wimboot_extraction(ctx);
                if (ret)