*/
/*
- * Copyright (C) 2012-2016 Eric Biggers
+ * Copyright 2012-2023 Eric Biggers
*
* 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
le64 last_write_time;
/*
- * Usually this is the SHA-1 message digest of the file's "contents"
- * (the unnamed data stream).
- *
- * If the file has FILE_ATTRIBUTE_REPARSE_POINT set, then this is
- * instead usually the SHA-1 message digest of the uncompressed reparse
- * point data.
- *
- * However, there are some special rules that need to be applied to
- * interpret this field correctly when extra stream entries are present.
- * See the code for details.
+ * Usually this is the SHA-1 message digest of the file's contents, or
+ * all zeroes if the file is a directory or is empty. However, special
+ * rules apply if the file has FILE_ATTRIBUTE_REPARSE_POINT set or has
+ * named data streams. See assign_stream_types_unencrypted().
*/
- u8 default_hash[SHA1_HASH_SIZE];
+ u8 main_hash[SHA1_HASH_SIZE];
/* Unknown field (maybe accidental padding) */
le32 unknown_0x54;
{
const struct wim_inode *inode = dentry->d_inode;
size_t len;
+ unsigned num_unnamed_streams = 0;
+ bool have_named_data_stream = false;
len = dentry_min_len_with_names(dentry->d_name_nbytes,
dentry->d_short_name_nbytes);
if (inode->i_extra)
len += ALIGN(inode->i_extra->size, 8);
- if (!(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
- /*
- * Extra stream entries:
- *
- * - Use one extra stream entry for each named data stream
- * - Use one extra stream entry for the unnamed data stream when there is either:
- * - a reparse point stream
- * - at least one named data stream (for Windows PE bug workaround)
- * - Use one extra stream entry for the reparse point stream if there is one
- */
- bool have_named_data_stream = false;
- bool have_reparse_point_stream = false;
+ /*
+ * Calculate the total length of the extra stream entries that will be
+ * written. To match DISM, some odd rules need to be followed here.
+ * See write_dentry_streams() for explanation. Keep this in sync with
+ * write_dentry_streams()!
+ */
+ if (inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED) {
+ num_unnamed_streams++;
+ } else {
for (unsigned i = 0; i < inode->i_num_streams; i++) {
const struct wim_inode_stream *strm = &inode->i_streams[i];
+
if (stream_is_named_data_stream(strm)) {
len += stream_out_total_length(strm);
have_named_data_stream = true;
- } else if (strm->stream_type == STREAM_TYPE_REPARSE_POINT) {
- wimlib_assert(inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT);
- have_reparse_point_stream = true;
}
}
-
- if (have_named_data_stream || have_reparse_point_stream) {
- if (have_reparse_point_stream)
- len += ALIGN(sizeof(struct wim_extra_stream_entry_on_disk), 8);
- len += ALIGN(sizeof(struct wim_extra_stream_entry_on_disk), 8);
- }
+ if (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
+ num_unnamed_streams++;
+ if (!(inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY))
+ num_unnamed_streams++;
}
-
+ if (num_unnamed_streams > 1 || have_named_data_stream)
+ len += num_unnamed_streams *
+ ALIGN(sizeof(struct wim_extra_stream_entry_on_disk), 8);
return len;
}
/*
* Set the type of each stream for an unencrypted file.
*
- * There will be an unnamed data stream, a reparse point stream, or both an
- * unnamed data stream and a reparse point stream. In addition, there may be
- * named data streams.
- *
- * NOTE: if the file has a reparse point stream or at least one named data
- * stream, then WIMGAPI puts *all* streams in the extra stream entries and
- * leaves the default stream hash zeroed. wimlib now does the same. However,
- * for input we still support the default hash field being used, since wimlib
- * used to use it and MS software is somewhat accepting of it as well.
+ * To specify the streams of each file, the WIM provides a main_hash and an
+ * optional list of "extra stream entries". Each extra stream entry is a
+ * (name, hash) pair where the name is optional. Hashes can be the special
+ * value of zero_hash, which means the stream is empty (zero-length).
+ *
+ * While extra stream entries with names always refer to "named data streams",
+ * the main hash and any extra unnamed hashes can be hard to interpret. This is
+ * because the WIM file format unfortunately doesn't make it very clear which is
+ * the unnamed data stream (i.e. standard file contents) and which is the
+ * reparse stream. The way this ambiguity is resolved (based on what MS
+ * software seems to do) is by (1) a file can have at most one unnamed data
+ * stream and at most one reparse stream, (2) a reparse stream is present if and
+ * only if the file has FILE_ATTRIBUTE_REPARSE_POINT, and (3) the reparse
+ * stream, if present, is stored before the unnamed data stream if present
+ * (considering main_hash to come before any extra hashes). Note: directories
+ * need not have an unnamed data stream stored, even with a zero hash, as
+ * "unnamed data stream" isn't meaningful for a directory in the first place.
+ *
+ * With those rules in mind, one would expect that the first unnamed stream
+ * would use main_hash, and the second (if present) would use an extra stream
+ * entry. However, there is another quirk that we must be compatible with:
+ * sometimes main_hash isn't used and only extra stream entries are used. To
+ * handle this, we ignore main_hash if it is zero and there is at least one
+ * unnamed extra stream entry. This works correctly as long as a zero main_hash
+ * and an unnamed extra stream entry is never used to represent an empty reparse
+ * stream and an unnamed data stream. (It's not, as the reparse stream always
+ * goes in the extra stream entries in this case. See write_dentry_streams().)
*/
static void
assign_stream_types_unencrypted(struct wim_inode *inode)
{
- bool found_reparse_point_stream = false;
+ bool found_reparse_stream = false;
bool found_unnamed_data_stream = false;
- struct wim_inode_stream *unnamed_stream_with_zero_hash = NULL;
for (unsigned i = 0; i < inode->i_num_streams; i++) {
struct wim_inode_stream *strm = &inode->i_streams[i];
if (stream_is_named(strm)) {
- /* Named data stream */
+ /* Named extra stream entry */
strm->stream_type = STREAM_TYPE_DATA;
} else if (i != 0 || !is_zero_hash(strm->_stream_hash)) {
- /* Unnamed stream in the extra stream entries, OR the
- * default stream in the dentry provided that it has a
- * nonzero hash. */
+ /* Unnamed extra stream entry or a nonzero main_hash */
if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
- !found_reparse_point_stream) {
- found_reparse_point_stream = true;
+ !found_reparse_stream) {
+ found_reparse_stream = true;
strm->stream_type = STREAM_TYPE_REPARSE_POINT;
} else if (!found_unnamed_data_stream) {
found_unnamed_data_stream = true;
strm->stream_type = STREAM_TYPE_DATA;
- }
- } else if (!unnamed_stream_with_zero_hash) {
- unnamed_stream_with_zero_hash = strm;
- }
+ } /* Else, too many unnamed streams were found. */
+
+ } /* Else, it's a zero main_hash. */
}
- if (unnamed_stream_with_zero_hash) {
- int type = STREAM_TYPE_UNKNOWN;
- if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) &&
- !found_reparse_point_stream) {
- type = STREAM_TYPE_REPARSE_POINT;
- } else if (!found_unnamed_data_stream) {
- type = STREAM_TYPE_DATA;
- }
- unnamed_stream_with_zero_hash->stream_type = type;
+ /* If needed, use the zero main_hash. */
+ if (!found_reparse_stream && !found_unnamed_data_stream) {
+ inode->i_streams[0].stream_type =
+ (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) ?
+ STREAM_TYPE_REPARSE_POINT : STREAM_TYPE_DATA;
}
}
*/
static int
setup_inode_streams(const u8 *p, const u8 *end, struct wim_inode *inode,
- unsigned num_extra_streams, const u8 *default_hash,
+ unsigned num_extra_streams, const u8 *main_hash,
u64 *offset_p)
{
const u8 *orig_p = p;
return WIMLIB_ERR_NOMEM;
}
- /* Use the default hash field for the first stream */
+ /* Use main_hash for the first stream. */
inode->i_streams[0].stream_name = (utf16lechar *)NO_STREAM_NAME;
- copy_hash(inode->i_streams[0]._stream_hash, default_hash);
+ copy_hash(inode->i_streams[0]._stream_hash, main_hash);
inode->i_streams[0].stream_type = STREAM_TYPE_UNKNOWN;
inode->i_streams[0].stream_id = 0;
- /* Read the extra stream entries */
+ /* Read the extra stream entries. */
for (unsigned i = 1; i < inode->i_num_streams; i++) {
struct wim_inode_stream *strm;
const struct wim_extra_stream_entry_on_disk *disk_strm;
&buf[buf_len],
inode,
le16_to_cpu(disk_dentry->num_extra_streams),
- disk_dentry->default_hash,
+ disk_dentry->main_hash,
&offset);
if (ret)
goto err_free_dentry;
return p;
}
+/*
+ * Write the stream references for a WIM dentry. To be compatible with DISM, we
+ * follow the below rules:
+ *
+ * 1. If the file has FILE_ATTRIBUTE_ENCRYPTED, then only the EFSRPC_RAW_DATA
+ * stream is stored. Otherwise, the streams that are stored are:
+ * - Reparse stream if the file has FILE_ATTRIBUTE_REPARSE_POINT
+ * - Unnamed data stream if the file doesn't have FILE_ATTRIBUTE_DIRECTORY
+ * - Named data streams
+ *
+ * 2. If only one stream is being stored and it is the EFSRPC_RAW_DATA, unnamed
+ * data, or reparse stream, then its hash goes in main_hash, and no extra
+ * stream entries are stored. Otherwise, *all* streams go in the extra
+ * stream entries, and main_hash is left zeroed!
+ *
+ * 3. If both the reparse stream and unnamed data stream are being stored, then
+ * the reparse stream comes first.
+ *
+ * 4. The unnamed stream(s) come before the named stream(s). (Actually, DISM
+ * puts the named streams between the first and second unnamed streams, but
+ * this is incompatible with itself... Tested with DISM 10.0.20348.681.)
+ *
+ * wimlib v1.14.1 and earlier behaved slightly differently for directories.
+ * First, wimlib always put the hash of the reparse stream in an extra stream
+ * entry, never in main_hash. This difference vs. DISM went unnoticed for a
+ * long time, but eventually it was found that it broke the Windows 8 setup
+ * wizard. Second, when a directory had any extra streams, wimlib created an
+ * extra stream entry to represent the (empty) unnamed data stream. However,
+ * DISM now rejects that (though I think it used to accept it). There isn't
+ * really any such thing as "unnamed data stream" for a directory.
+ *
+ * Keep this in sync with dentry_out_total_length()!
+ */
+static u8 *
+write_dentry_streams(const struct wim_inode *inode,
+ struct wim_dentry_on_disk *disk_dentry, u8 *p)
+{
+ const u8 *unnamed_data_stream_hash = zero_hash;
+ const u8 *reparse_stream_hash = zero_hash;
+ const u8 *efsrpc_stream_hash = zero_hash;
+ const u8 *unnamed_stream_hashes[2] = { zero_hash };
+ unsigned num_unnamed_streams = 0;
+ unsigned num_named_streams = 0;
+
+ for (unsigned i = 0; i < inode->i_num_streams; i++) {
+ const struct wim_inode_stream *strm = &inode->i_streams[i];
+
+ switch (strm->stream_type) {
+ case STREAM_TYPE_DATA:
+ if (stream_is_named(strm))
+ num_named_streams++;
+ else
+ unnamed_data_stream_hash = stream_hash(strm);
+ break;
+ case STREAM_TYPE_REPARSE_POINT:
+ reparse_stream_hash = stream_hash(strm);
+ break;
+ case STREAM_TYPE_EFSRPC_RAW_DATA:
+ efsrpc_stream_hash = stream_hash(strm);
+ break;
+ }
+ }
+
+ if (inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED) {
+ unnamed_stream_hashes[num_unnamed_streams++] = efsrpc_stream_hash;
+ num_named_streams = 0;
+ } else {
+ if (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
+ unnamed_stream_hashes[num_unnamed_streams++] = reparse_stream_hash;
+ if (!(inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY))
+ unnamed_stream_hashes[num_unnamed_streams++] = unnamed_data_stream_hash;
+ }
+
+ if (num_unnamed_streams <= 1 && num_named_streams == 0) {
+ /* No extra stream entries are needed. */
+ copy_hash(disk_dentry->main_hash, unnamed_stream_hashes[0]);
+ disk_dentry->num_extra_streams = 0;
+ return p;
+ }
+
+ /* Else, all streams go in extra stream entries. */
+ copy_hash(disk_dentry->main_hash, zero_hash);
+ wimlib_assert(num_unnamed_streams + num_named_streams <= 0xFFFF);
+ disk_dentry->num_extra_streams = cpu_to_le16(num_unnamed_streams +
+ num_named_streams);
+ for (unsigned i = 0; i < num_unnamed_streams; i++)
+ p = write_extra_stream_entry(p, NO_STREAM_NAME,
+ unnamed_stream_hashes[i]);
+ for (unsigned i = 0; i < inode->i_num_streams; i++) {
+ const struct wim_inode_stream *strm = &inode->i_streams[i];
+
+ if (stream_is_named_data_stream(strm)) {
+ p = write_extra_stream_entry(p, strm->stream_name,
+ stream_hash(strm));
+ }
+ }
+ return p;
+}
+
/*
* Write a WIM dentry to an output buffer.
*
disk_dentry->length = cpu_to_le64(p - orig_p);
- /* Streams */
-
- if (unlikely(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
- const struct wim_inode_stream *efs_strm;
- const u8 *efs_hash;
-
- efs_strm = inode_get_unnamed_stream(inode, STREAM_TYPE_EFSRPC_RAW_DATA);
- efs_hash = efs_strm ? stream_hash(efs_strm) : zero_hash;
- copy_hash(disk_dentry->default_hash, efs_hash);
- disk_dentry->num_extra_streams = cpu_to_le16(0);
- } else {
- /*
- * Extra stream entries:
- *
- * - Use one extra stream entry for each named data stream
- * - Use one extra stream entry for the unnamed data stream when there is either:
- * - a reparse point stream
- * - at least one named data stream (for Windows PE bug workaround)
- * - Use one extra stream entry for the reparse point stream if there is one
- */
- bool have_named_data_stream = false;
- bool have_reparse_point_stream = false;
- const u8 *unnamed_data_stream_hash = zero_hash;
- const u8 *reparse_point_hash;
- for (unsigned i = 0; i < inode->i_num_streams; i++) {
- const struct wim_inode_stream *strm = &inode->i_streams[i];
- if (strm->stream_type == STREAM_TYPE_DATA) {
- if (stream_is_named(strm))
- have_named_data_stream = true;
- else
- unnamed_data_stream_hash = stream_hash(strm);
- } else if (strm->stream_type == STREAM_TYPE_REPARSE_POINT) {
- have_reparse_point_stream = true;
- reparse_point_hash = stream_hash(strm);
- }
- }
-
- if (unlikely(have_reparse_point_stream || have_named_data_stream)) {
-
- unsigned num_extra_streams = 0;
-
- copy_hash(disk_dentry->default_hash, zero_hash);
-
- if (have_reparse_point_stream) {
- p = write_extra_stream_entry(p, NO_STREAM_NAME,
- reparse_point_hash);
- num_extra_streams++;
- }
-
- p = write_extra_stream_entry(p, NO_STREAM_NAME,
- unnamed_data_stream_hash);
- num_extra_streams++;
-
- for (unsigned i = 0; i < inode->i_num_streams; i++) {
- const struct wim_inode_stream *strm = &inode->i_streams[i];
- if (stream_is_named_data_stream(strm)) {
- p = write_extra_stream_entry(p, strm->stream_name,
- stream_hash(strm));
- num_extra_streams++;
- }
- }
- wimlib_assert(num_extra_streams <= 0xFFFF);
-
- disk_dentry->num_extra_streams = cpu_to_le16(num_extra_streams);
- } else {
- copy_hash(disk_dentry->default_hash, unnamed_data_stream_hash);
- disk_dentry->num_extra_streams = cpu_to_le16(0);
- }
- }
-
- return p;
+ /*
+ * Set disk_dentry->main_hash and disk_dentry->num_extra_streams,
+ * and write any extra stream entries that are needed.
+ */
+ return write_dentry_streams(inode, disk_dentry, p);
}
static int
git://wimlib.net / wimlib / commitdiff