Update XZ Utils to 5.0.5

src/liblzma/common/alone_decoder.c

 ///////////////////////////////////////////////////////////////////////////////
 //
 /// \file       alone_decoder.c
 /// \brief      Decoder for LZMA_Alone files
 //
 //  Author:     Lasse Collin
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "alone_decoder.h"
 #include "lzma_decoder.h"
 #include "lz_decoder.h"
 
 
 struct lzma_coder_s {
         lzma_next_coder next;
 
         enum {
                 SEQ_PROPERTIES,
                 SEQ_DICTIONARY_SIZE,
                 SEQ_UNCOMPRESSED_SIZE,
                 SEQ_CODER_INIT,
                 SEQ_CODE,
         } sequence;
 
+        /// If true, reject files that are unlikely to be .lzma files.
+        /// If false, more non-.lzma files get accepted and will give
+        /// LZMA_DATA_ERROR either immediately or after a few output bytes.
+        bool picky;
+
         /// Position in the header fields
         size_t pos;
 
         /// Uncompressed size decoded from the header
         lzma_vli uncompressed_size;
 
         /// Memory usage limit
         uint64_t memlimit;
 
         /// Amount of memory actually needed (only an estimate)
@@ skipping 22 matching lines @@
 
                 coder->sequence = SEQ_DICTIONARY_SIZE;
                 ++*in_pos;
                 break;
 
         case SEQ_DICTIONARY_SIZE:
                 coder->options.dict_size
                                 |= (size_t)(in[*in_pos]) << (coder->pos * 8);
 
                 if (++coder->pos == 4) {
-                        if (coder->options.dict_size != UINT32_MAX) {
+                        if (coder->picky && coder->options.dict_size
+                                        != UINT32_MAX) {
                                 // A hack to ditch tons of false positives:
                                 // We allow only dictionary sizes that are
                                 // 2^n or 2^n + 2^(n-1). LZMA_Alone created
                                 // only files with 2^n, but accepts any
-                                // dictionary size. If someone complains, this
-                                // will be reconsidered.
+                                // dictionary size.
                                 uint32_t d = coder->options.dict_size - 1;
                                 d |= d >> 2;
                                 d |= d >> 3;
                                 d |= d >> 4;
                                 d |= d >> 8;
                                 d |= d >> 16;
                                 ++d;
 
                                 if (d != coder->options.dict_size)
                                         return LZMA_FORMAT_ERROR;
                         }
 
                         coder->pos = 0;
                         coder->sequence = SEQ_UNCOMPRESSED_SIZE;
                 }
 
                 ++*in_pos;
                 break;
 
         case SEQ_UNCOMPRESSED_SIZE:
                 coder->uncompressed_size
                                 |= (lzma_vli)(in[*in_pos]) << (coder->pos * 8);
                 ++*in_pos;
                 if (++coder->pos < 8)
                         break;
 
                 // Another hack to ditch false positives: Assume that
                 // if the uncompressed size is known, it must be less
-                // than 256 GiB. Again, if someone complains, this
-                // will be reconsidered.
-                if (coder->uncompressed_size != LZMA_VLI_UNKNOWN
+                // than 256 GiB.
+                if (coder->picky
+                                && coder->uncompressed_size != LZMA_VLI_UNKNOWN
                                 && coder->uncompressed_size
                                         >= (LZMA_VLI_C(1) << 38))
                         return LZMA_FORMAT_ERROR;
 
                 // Calculate the memory usage so that it is ready
                 // for SEQ_CODER_INIT.
                 coder->memusage = lzma_lzma_decoder_memusage(&coder->options)
                                 + LZMA_MEMUSAGE_BASE;
 
                 coder->pos = 0;
@@ skipping 63 matching lines @@
 
                 coder->memlimit = new_memlimit;
         }
 
         return LZMA_OK;
 }
 
 
 extern lzma_ret
 lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
-                uint64_t memlimit)
+                uint64_t memlimit, bool picky)
 {
         lzma_next_coder_init(&lzma_alone_decoder_init, next, allocator);
 
         if (memlimit == 0)
                 return LZMA_PROG_ERROR;
 
         if (next->coder == NULL) {
                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
                 if (next->coder == NULL)
                         return LZMA_MEM_ERROR;
 
                 next->code = &alone_decode;
                 next->end = &alone_decoder_end;
                 next->memconfig = &alone_decoder_memconfig;
                 next->coder->next = LZMA_NEXT_CODER_INIT;
         }
 
         next->coder->sequence = SEQ_PROPERTIES;
+        next->coder->picky = picky;
         next->coder->pos = 0;
         next->coder->options.dict_size = 0;
         next->coder->options.preset_dict = NULL;
         next->coder->options.preset_dict_size = 0;
         next->coder->uncompressed_size = 0;
         next->coder->memlimit = memlimit;
         next->coder->memusage = LZMA_MEMUSAGE_BASE;
 
         return LZMA_OK;
 }
 
 
 extern LZMA_API(lzma_ret)
 lzma_alone_decoder(lzma_stream *strm, uint64_t memlimit)
 {
-        lzma_next_strm_init(lzma_alone_decoder_init, strm, memlimit);
+        lzma_next_strm_init(lzma_alone_decoder_init, strm, memlimit, false);
 
         strm->internal->supported_actions[LZMA_RUN] = true;
         strm->internal->supported_actions[LZMA_FINISH] = true;
 
         return LZMA_OK;
 }