unlzma: add comments about possible bug from BZ 2689

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/archival/libarchive/decompress_unlzma.c b/archival/libarchive/decompress_unlzma.c
index a89b846a0..3d99e1388 100644
--- a/archival/libarchive/decompress_unlzma.c
+++ b/archival/libarchive/decompress_unlzma.c
@@ -237,6 +237,9 @@ unpack_lzma_stream(transformer_aux_data_t *aux UNUSED_PARAM, int src_fd, int dst
         pos_state_mask = (1 << pb) - 1;
         literal_pos_mask = (1 << lp) - 1;
 
+        /* Example values from linux-3.3.4.tar.lzma:
+         * dict_size: 64M, dst_size: 2^64-1
+         */
         header.dict_size = SWAP_LE32(header.dict_size);
         header.dst_size = SWAP_LE64(header.dst_size);
 
@@ -443,6 +446,9 @@ unpack_lzma_stream(transformer_aux_data_t *aux UNUSED_PARAM, int src_fd, int dst
                                 }
                                 len--;
                         } while (len != 0 && buffer_pos < header.dst_size);
+                        /* FIXME: ...........^^^^^
+                         * shouldn't it be "global_pos + buffer_pos < header.dst_size"?
+                         */
                 }
         }