Fix decoding of Blocks that have only Block Header.

diff --git a/src/liblzma/common/block_decoder.c b/src/liblzma/common/block_decoder.c
index af2b020..820fee0 100644 (file)
--- a/src/liblzma/common/block_decoder.c
+++ b/src/liblzma/common/block_decoder.c
@@ -345,28 +345,7 @@ lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 
        return_if_error(lzma_check_init(&next->coder->check, options->check));
 
-       if (!options->has_eopm && options->uncompressed_size == 0) {
-               if (!is_size_valid(0, options->compressed_size))
-                       return LZMA_PROG_ERROR;
-
-               if (options->check != LZMA_CHECK_NONE) {
-                       lzma_check_finish(&next->coder->check, options->check);
-                       next->coder->sequence = SEQ_CHECK;
-               } else if (options->handle_padding) {
-                       next->coder->sequence = SEQ_PADDING;
-               } else {
-                       next->coder->sequence = SEQ_END;
-               }
-       } else {
-               next->coder->sequence = SEQ_CODE;
-       }
-
-       return_if_error(lzma_raw_decoder_init(&next->coder->next, allocator,
-                       options->filters, options->has_eopm
-                               ? LZMA_VLI_VALUE_UNKNOWN
-                               : options->uncompressed_size,
-                       true));
-
+       next->coder->sequence = SEQ_CODE;
        next->coder->options = options;
        next->coder->pos = 0;
        next->coder->total_size = options->header_size;
@@ -379,7 +358,19 @@ lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
        next->coder->tmp = 0;
        next->coder->size_of_backward_size = 0;
 
-       return LZMA_OK;
+       if (!options->has_eopm && options->uncompressed_size == 0) {
+               // The Compressed Data field is empty, thus we skip SEQ_CODE
+               // phase completely.
+               const lzma_ret ret = update_sequence(next->coder);
+               if (ret != LZMA_OK && ret != LZMA_STREAM_END)
+                       return LZMA_PROG_ERROR;
+       }
+
+       return lzma_raw_decoder_init(&next->coder->next, allocator,
+                       options->filters, options->has_eopm
+                               ? LZMA_VLI_VALUE_UNKNOWN
+                               : options->uncompressed_size,
+                       true);
 }