Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/common/index_hash.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       index_hash.c
+/// \brief      Validates Index by using a hash function
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "common.h"
+#include "index.h"
+#include "check.h"
+
+
+typedef struct {
+        /// Sum of the Block sizes (including Block Padding)
+        lzma_vli blocks_size;
+
+        /// Sum of the Uncompressed Size fields
+        lzma_vli uncompressed_size;
+
+        /// Number of Records
+        lzma_vli count;
+
+        /// Size of the List of Index Records as bytes
+        lzma_vli index_list_size;
+
+        /// Check calculated from Unpadded Sizes and Uncompressed Sizes.
+        lzma_check_state check;
+
+} lzma_index_hash_info;
+
+
+struct lzma_index_hash_s {
+        enum {
+                SEQ_BLOCK,
+                SEQ_COUNT,
+                SEQ_UNPADDED,
+                SEQ_UNCOMPRESSED,
+                SEQ_PADDING_INIT,
+                SEQ_PADDING,
+                SEQ_CRC32,
+        } sequence;
+
+        /// Information collected while decoding the actual Blocks.
+        lzma_index_hash_info blocks;
+
+        /// Information collected from the Index field.
+        lzma_index_hash_info records;
+
+        /// Number of Records not fully decoded
+        lzma_vli remaining;
+
+        /// Unpadded Size currently being read from an Index Record.
+        lzma_vli unpadded_size;
+
+        /// Uncompressed Size currently being read from an Index Record.
+        lzma_vli uncompressed_size;
+
+        /// Position in variable-length integers when decoding them from
+        /// the List of Records.
+        size_t pos;
+
+        /// CRC32 of the Index
+        uint32_t crc32;
+};
+
+
+extern LZMA_API(lzma_index_hash *)
+lzma_index_hash_init(lzma_index_hash *index_hash, lzma_allocator *allocator)
+{
+        if (index_hash == NULL) {
+                index_hash = lzma_alloc(sizeof(lzma_index_hash), allocator);
+                if (index_hash == NULL)
+                        return NULL;
+        }
+
+        index_hash->sequence = SEQ_BLOCK;
+        index_hash->blocks.blocks_size = 0;
+        index_hash->blocks.uncompressed_size = 0;
+        index_hash->blocks.count = 0;
+        index_hash->blocks.index_list_size = 0;
+        index_hash->records.blocks_size = 0;
+        index_hash->records.uncompressed_size = 0;
+        index_hash->records.count = 0;
+        index_hash->records.index_list_size = 0;
+        index_hash->unpadded_size = 0;
+        index_hash->uncompressed_size = 0;
+        index_hash->pos = 0;
+        index_hash->crc32 = 0;
+
+        // These cannot fail because LZMA_CHECK_BEST is known to be supported.
+        (void)lzma_check_init(&index_hash->blocks.check, LZMA_CHECK_BEST);
+        (void)lzma_check_init(&index_hash->records.check, LZMA_CHECK_BEST);
+
+        return index_hash;
+}
+
+
+extern LZMA_API(void)
+lzma_index_hash_end(lzma_index_hash *index_hash, lzma_allocator *allocator)
+{
+        lzma_free(index_hash, allocator);
+        return;
+}
+
+
+extern LZMA_API(lzma_vli)
+lzma_index_hash_size(const lzma_index_hash *index_hash)
+{
+        // Get the size of the Index from ->blocks instead of ->records for
+        // cases where application wants to know the Index Size before
+        // decoding the Index.
+        return index_size(index_hash->blocks.count,
+                        index_hash->blocks.index_list_size);
+}
+
+
+/// Updates the sizes and the hash without any validation.
+static lzma_ret
+hash_append(lzma_index_hash_info *info, lzma_vli unpadded_size,
+                lzma_vli uncompressed_size)
+{
+        info->blocks_size += vli_ceil4(unpadded_size);
+        info->uncompressed_size += uncompressed_size;
+        info->index_list_size += lzma_vli_size(unpadded_size)
+                        + lzma_vli_size(uncompressed_size);
+        ++info->count;
+
+        const lzma_vli sizes[2] = { unpadded_size, uncompressed_size };
+        lzma_check_update(&info->check, LZMA_CHECK_BEST,
+                        (const uint8_t *)(sizes), sizeof(sizes));
+
+        return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_index_hash_append(lzma_index_hash *index_hash, lzma_vli unpadded_size,
+                lzma_vli uncompressed_size)
+{
+        // Validate the arguments.
+        if (index_hash->sequence != SEQ_BLOCK
+                        || unpadded_size < UNPADDED_SIZE_MIN
+                        || unpadded_size > UNPADDED_SIZE_MAX
+                        || uncompressed_size > LZMA_VLI_MAX)
+                return LZMA_PROG_ERROR;
+
+        // Update the hash.
+        return_if_error(hash_append(&index_hash->blocks,
+                        unpadded_size, uncompressed_size));
+
+        // Validate the properties of *info are still in allowed limits.
+        if (index_hash->blocks.blocks_size > LZMA_VLI_MAX
+                        || index_hash->blocks.uncompressed_size > LZMA_VLI_MAX
+                        || index_size(index_hash->blocks.count,
+                                        index_hash->blocks.index_list_size)
+                                > LZMA_BACKWARD_SIZE_MAX
+                        || index_stream_size(index_hash->blocks.blocks_size,
+                                        index_hash->blocks.count,
+                                        index_hash->blocks.index_list_size)
+                                > LZMA_VLI_MAX)
+                return LZMA_DATA_ERROR;
+
+        return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_index_hash_decode(lzma_index_hash *index_hash, const uint8_t *in,
+                size_t *in_pos, size_t in_size)
+{
+        // Catch zero input buffer here, because in contrast to Index encoder
+        // and decoder functions, applications call this function directly
+        // instead of via lzma_code(), which does the buffer checking.
+        if (*in_pos >= in_size)
+                return LZMA_BUF_ERROR;
+
+        // NOTE: This function has many similarities to index_encode() and
+        // index_decode() functions found from index_encoder.c and
+        // index_decoder.c. See the comments especially in index_encoder.c.
+        const size_t in_start = *in_pos;
+        lzma_ret ret = LZMA_OK;
+
+        while (*in_pos < in_size)
+        switch (index_hash->sequence) {
+        case SEQ_BLOCK:
+                // Check the Index Indicator is present.
+                if (in[(*in_pos)++] != 0x00)
+                        return LZMA_DATA_ERROR;
+
+                index_hash->sequence = SEQ_COUNT;
+                break;
+
+        case SEQ_COUNT: {
+                ret = lzma_vli_decode(&index_hash->remaining,
+                                &index_hash->pos, in, in_pos, in_size);
+                if (ret != LZMA_STREAM_END)
+                        goto out;
+
+                // The count must match the count of the Blocks decoded.
+                if (index_hash->remaining != index_hash->blocks.count)
+                        return LZMA_DATA_ERROR;
+
+                ret = LZMA_OK;
+                index_hash->pos = 0;
+
+                // Handle the special case when there are no Blocks.
+                index_hash->sequence = index_hash->remaining == 0
+                                ? SEQ_PADDING_INIT : SEQ_UNPADDED;
+                break;
+        }
+
+        case SEQ_UNPADDED:
+        case SEQ_UNCOMPRESSED: {
+                lzma_vli *size = index_hash->sequence == SEQ_UNPADDED
+                                ? &index_hash->unpadded_size
+                                : &index_hash->uncompressed_size;
+
+                ret = lzma_vli_decode(size, &index_hash->pos,
+                                in, in_pos, in_size);
+                if (ret != LZMA_STREAM_END)
+                        goto out;
+
+                ret = LZMA_OK;
+                index_hash->pos = 0;
+
+                if (index_hash->sequence == SEQ_UNPADDED) {
+                        if (index_hash->unpadded_size < UNPADDED_SIZE_MIN
+                                        || index_hash->unpadded_size
+                                                > UNPADDED_SIZE_MAX)
+                                return LZMA_DATA_ERROR;
+
+                        index_hash->sequence = SEQ_UNCOMPRESSED;
+                } else {
+                        // Update the hash.
+                        return_if_error(hash_append(&index_hash->records,
+                                        index_hash->unpadded_size,
+                                        index_hash->uncompressed_size));
+
+                        // Verify that we don't go over the known sizes. Note
+                        // that this validation is simpler than the one used
+                        // in lzma_index_hash_append(), because here we know
+                        // that values in index_hash->blocks are already
+                        // validated and we are fine as long as we don't
+                        // exceed them in index_hash->records.
+                        if (index_hash->blocks.blocks_size
+                                        < index_hash->records.blocks_size
+                                        || index_hash->blocks.uncompressed_size
+                                        < index_hash->records.uncompressed_size
+                                        || index_hash->blocks.index_list_size
+                                        < index_hash->records.index_list_size)
+                                return LZMA_DATA_ERROR;
+
+                        // Check if this was the last Record.
+                        index_hash->sequence = --index_hash->remaining == 0
+                                        ? SEQ_PADDING_INIT : SEQ_UNPADDED;
+                }
+
+                break;
+        }
+
+        case SEQ_PADDING_INIT:
+                index_hash->pos = (LZMA_VLI_C(4) - index_size_unpadded(
+                                index_hash->records.count,
+                                index_hash->records.index_list_size)) & 3;
+                index_hash->sequence = SEQ_PADDING;
+
+        // Fall through
+
+        case SEQ_PADDING:
+                if (index_hash->pos > 0) {
+                        --index_hash->pos;
+                        if (in[(*in_pos)++] != 0x00)
+                                return LZMA_DATA_ERROR;
+
+                        break;
+                }
+
+                // Compare the sizes.
+                if (index_hash->blocks.blocks_size
+                                != index_hash->records.blocks_size
+                                || index_hash->blocks.uncompressed_size
+                                != index_hash->records.uncompressed_size
+                                || index_hash->blocks.index_list_size
+                                != index_hash->records.index_list_size)
+                        return LZMA_DATA_ERROR;
+
+                // Finish the hashes and compare them.
+                lzma_check_finish(&index_hash->blocks.check, LZMA_CHECK_BEST);
+                lzma_check_finish(&index_hash->records.check, LZMA_CHECK_BEST);
+                if (memcmp(index_hash->blocks.check.buffer.u8,
+                                index_hash->records.check.buffer.u8,
+                                lzma_check_size(LZMA_CHECK_BEST)) != 0)
+                        return LZMA_DATA_ERROR;
+
+                // Finish the CRC32 calculation.
+                index_hash->crc32 = lzma_crc32(in + in_start,
+                                *in_pos - in_start, index_hash->crc32);
+
+                index_hash->sequence = SEQ_CRC32;
+
+        // Fall through
+
+        case SEQ_CRC32:
+                do {
+                        if (*in_pos == in_size)
+                                return LZMA_OK;
+
+                        if (((index_hash->crc32 >> (index_hash->pos * 8))
+                                        & 0xFF) != in[(*in_pos)++])
+                                return LZMA_DATA_ERROR;
+
+                } while (++index_hash->pos < 4);
+
+                return LZMA_STREAM_END;
+
+        default:
+                assert(0);
+                return LZMA_PROG_ERROR;
+        }
+
+out:
+        // Update the CRC32,
+        index_hash->crc32 = lzma_crc32(in + in_start,
+                        *in_pos - in_start, index_hash->crc32);
+
+        return ret;
+}