1 files changed, 349 insertions, 0 deletions
diff --git a/lib/sqfs/xattr/xattr_reader.c b/lib/sqfs/xattr/xattr_reader.c
new file mode 100644
index 0000000..37f222a
--- /dev/null
+++ b/lib/sqfs/xattr/xattr_reader.c
@@ -0,0 +1,349 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * xattr_reader.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/xattr_reader.h"
+#include "sqfs/meta_reader.h"
+#include "sqfs/super.h"
+#include "sqfs/xattr.h"
+#include "sqfs/error.h"
+#include "sqfs/block.h"
+#include "sqfs/io.h"
+#include "util.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+struct sqfs_xattr_reader_t {
+	sqfs_object_t base;
+
+	sqfs_u64 xattr_start;
+	sqfs_u64 xattr_end;
+
+	size_t num_id_blocks;
+	size_t num_ids;
+
+	sqfs_u64 *id_block_starts;
+
+	sqfs_meta_reader_t *idrd;
+	sqfs_meta_reader_t *kvrd;
+};
+
+static sqfs_object_t *xattr_reader_copy(const sqfs_object_t *obj)
+{
+	const sqfs_xattr_reader_t *xr = (const sqfs_xattr_reader_t *)obj;
+	sqfs_xattr_reader_t *copy = malloc(sizeof(*copy));
+
+	if (copy == NULL)
+		return NULL;
+
+	memcpy(copy, xr, sizeof(*xr));
+
+	if (xr->kvrd != NULL) {
+		copy->kvrd = sqfs_copy(xr->kvrd);
+		if (copy->kvrd == NULL)
+			goto fail_kvrd;
+	}
+
+	if (xr->idrd != NULL) {
+		copy->idrd = sqfs_copy(xr->idrd);
+		if (copy->idrd == NULL)
+			goto fail_idrd;
+	}
+
+	if (xr->id_block_starts != NULL) {
+		copy->id_block_starts = alloc_array(sizeof(sqfs_u64),
+						    xr->num_id_blocks);
+		if (copy->id_block_starts == NULL)
+			goto fail_idblk;
+
+		memcpy(copy->id_block_starts, xr->id_block_starts,
+		       sizeof(sqfs_u64) * xr->num_id_blocks);
+	}
+
+	return (sqfs_object_t *)copy;
+fail_idblk:
+	if (copy->idrd != NULL)
+		sqfs_destroy(copy->idrd);
+fail_idrd:
+	if (copy->kvrd != NULL)
+		sqfs_destroy(copy->kvrd);
+fail_kvrd:
+	free(copy);
+	return NULL;
+}
+
+static void xattr_reader_destroy(sqfs_object_t *obj)
+{
+	sqfs_xattr_reader_t *xr = (sqfs_xattr_reader_t *)obj;
+
+	if (xr->kvrd != NULL)
+		sqfs_destroy(xr->kvrd);
+
+	if (xr->idrd != NULL)
+		sqfs_destroy(xr->idrd);
+
+	free(xr->id_block_starts);
+	free(xr);
+}
+
+int sqfs_xattr_reader_load(sqfs_xattr_reader_t *xr, const sqfs_super_t *super,
+			   sqfs_file_t *file, sqfs_compressor_t *cmp)
+{
+	sqfs_xattr_id_table_t idtbl;
+	size_t i;
+	int err;
+
+	/* sanity check */
+	if (super->flags & SQFS_FLAG_NO_XATTRS)
+		return 0;
+
+	if (super->xattr_id_table_start == 0xFFFFFFFFFFFFFFFF)
+		return 0;
+
+	if (super->xattr_id_table_start >= super->bytes_used)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	/* cleanup pre-existing data */
+	if (xr->idrd != NULL) {
+		sqfs_destroy(xr->idrd);
+		xr->idrd = NULL;
+	}
+
+	if (xr->kvrd != NULL) {
+		sqfs_destroy(xr->kvrd);
+		xr->kvrd = NULL;
+	}
+
+	free(xr->id_block_starts);
+	xr->id_block_starts = NULL;
+
+	/* read the locations table */
+	err = file->read_at(file, super->xattr_id_table_start,
+			    &idtbl, sizeof(idtbl));
+	if (err)
+		return err;
+
+	xr->xattr_start = le64toh(idtbl.xattr_table_start);
+	xr->num_ids = le32toh(idtbl.xattr_ids);
+	xr->num_id_blocks =
+		(xr->num_ids * sizeof(sqfs_xattr_id_t)) / SQFS_META_BLOCK_SIZE;
+
+	if ((xr->num_ids * sizeof(sqfs_xattr_id_t)) % SQFS_META_BLOCK_SIZE)
+		xr->num_id_blocks += 1;
+
+	xr->id_block_starts = alloc_array(sizeof(sqfs_u64), xr->num_id_blocks);
+	if (xr->id_block_starts == NULL) {
+		if (errno == EOVERFLOW)
+			return SQFS_ERROR_OVERFLOW;
+		return SQFS_ERROR_ALLOC;
+	}
+
+	err = file->read_at(file, super->xattr_id_table_start + sizeof(idtbl),
+			    xr->id_block_starts,
+			    sizeof(sqfs_u64) * xr->num_id_blocks);
+	if (err)
+		goto fail_blocks;
+
+	for (i = 0; i < xr->num_id_blocks; ++i) {
+		xr->id_block_starts[i] = le64toh(xr->id_block_starts[i]);
+
+		if (xr->id_block_starts[i] > super->bytes_used) {
+			err = SQFS_ERROR_OUT_OF_BOUNDS;
+			goto fail_blocks;
+		}
+	}
+
+	/* create the meta data readers */
+	xr->idrd = sqfs_meta_reader_create(file, cmp, super->id_table_start,
+					   super->bytes_used);
+	if (xr->idrd == NULL)
+		goto fail_blocks;
+
+	xr->kvrd = sqfs_meta_reader_create(file, cmp, super->id_table_start,
+					   super->bytes_used);
+	if (xr->kvrd == NULL)
+		goto fail_idrd;
+
+	xr->xattr_end = super->bytes_used;
+	return 0;
+fail_idrd:
+	sqfs_destroy(xr->idrd);
+	xr->idrd = NULL;
+fail_blocks:
+	free(xr->id_block_starts);
+	xr->id_block_starts = NULL;
+	return err;
+}
+
+int sqfs_xattr_reader_read_key(sqfs_xattr_reader_t *xr,
+			       sqfs_xattr_entry_t **key_out)
+{
+	sqfs_xattr_entry_t key, *out;
+	const char *prefix;
+	size_t plen, total;
+	int ret;
+
+	ret = sqfs_meta_reader_read(xr->kvrd, &key, sizeof(key));
+	if (ret)
+		return ret;
+
+	key.type = le16toh(key.type);
+	key.size = le16toh(key.size);
+
+	prefix = sqfs_get_xattr_prefix(key.type & SQFS_XATTR_PREFIX_MASK);
+	if (prefix == NULL)
+		return SQFS_ERROR_UNSUPPORTED;
+
+	plen = strlen(prefix);
+
+	if (SZ_ADD_OV(plen, key.size, &total) || SZ_ADD_OV(total, 1, &total) ||
+	    SZ_ADD_OV(sizeof(*out), total, &total)) {
+		return SQFS_ERROR_OVERFLOW;
+	}
+
+	out = calloc(1, total);
+	if (out == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	*out = key;
+	memcpy(out->key, prefix, plen);
+
+	ret = sqfs_meta_reader_read(xr->kvrd, out->key + plen, key.size);
+	if (ret) {
+		free(out);
+		return ret;
+	}
+
+	*key_out = out;
+	return 0;
+}
+
+int sqfs_xattr_reader_read_value(sqfs_xattr_reader_t *xr,
+				 const sqfs_xattr_entry_t *key,
+				 sqfs_xattr_value_t **val_out)
+{
+	size_t offset, new_offset, size;
+	sqfs_xattr_value_t value, *out;
+	sqfs_u64 ref, start, new_start;
+	int ret;
+
+	ret = sqfs_meta_reader_read(xr->kvrd, &value, sizeof(value));
+	if (ret)
+		return ret;
+
+	if (key->type & SQFS_XATTR_FLAG_OOL) {
+		ret = sqfs_meta_reader_read(xr->kvrd, &ref, sizeof(ref));
+		if (ret)
+			return ret;
+
+		sqfs_meta_reader_get_position(xr->kvrd, &start, &offset);
+
+		new_start = xr->xattr_start + (ref >> 16);
+		if (new_start >= xr->xattr_end)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		new_offset = ref & 0xFFFF;
+		if (new_offset >= SQFS_META_BLOCK_SIZE)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		ret = sqfs_meta_reader_seek(xr->kvrd, new_start, new_offset);
+		if (ret)
+			return ret;
+	}
+
+	value.size = le32toh(value.size);
+
+	if (SZ_ADD_OV(sizeof(*out), value.size, &size) ||
+	    SZ_ADD_OV(size, 1, &size)) {
+		return SQFS_ERROR_OVERFLOW;
+	}
+
+	out = calloc(1, size);
+	if (out == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	*out = value;
+
+	ret = sqfs_meta_reader_read(xr->kvrd, out->value, value.size);
+	if (ret)
+		goto fail;
+
+	if (key->type & SQFS_XATTR_FLAG_OOL) {
+		ret = sqfs_meta_reader_seek(xr->kvrd, start, offset);
+		if (ret)
+			goto fail;
+	}
+
+	*val_out = out;
+	return 0;
+fail:
+	free(out);
+	return ret;
+}
+
+int sqfs_xattr_reader_seek_kv(sqfs_xattr_reader_t *xr,
+			      const sqfs_xattr_id_t *desc)
+{
+	sqfs_u32 offset = desc->xattr & 0xFFFF;
+	sqfs_u64 block = xr->xattr_start + (desc->xattr >> 16);
+
+	return sqfs_meta_reader_seek(xr->kvrd, block, offset);
+}
+
+int sqfs_xattr_reader_get_desc(sqfs_xattr_reader_t *xr, sqfs_u32 idx,
+			       sqfs_xattr_id_t *desc)
+{
+	size_t block, offset;
+	int ret;
+
+	memset(desc, 0, sizeof(*desc));
+
+	if (idx == 0xFFFFFFFF)
+		return 0;
+
+	if (xr->kvrd == NULL || xr->idrd == NULL)
+		return idx == 0 ? 0 : SQFS_ERROR_OUT_OF_BOUNDS;
+
+	if (idx >= xr->num_ids)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	offset = (idx * sizeof(*desc)) % SQFS_META_BLOCK_SIZE;
+	block = (idx * sizeof(*desc)) / SQFS_META_BLOCK_SIZE;
+
+	ret = sqfs_meta_reader_seek(xr->idrd, xr->id_block_starts[block],
+				    offset);
+	if (ret)
+		return ret;
+
+	ret = sqfs_meta_reader_read(xr->idrd, desc, sizeof(*desc));
+	if (ret)
+		return ret;
+
+	desc->xattr = le64toh(desc->xattr);
+	desc->count = le32toh(desc->count);
+	desc->size = le32toh(desc->size);
+	return 0;
+}
+
+sqfs_xattr_reader_t *sqfs_xattr_reader_create(sqfs_u32 flags)
+{
+	sqfs_xattr_reader_t *xr;
+
+	if (flags != 0)
+		return NULL;
+
+	xr = calloc(1, sizeof(*xr));
+	if (xr == NULL)
+		return NULL;
+
+	((sqfs_object_t *)xr)->copy = xattr_reader_copy;
+	((sqfs_object_t *)xr)->destroy = xattr_reader_destroy;
+	return xr;
+}