zip: read PKWARE Unix extra field metadata

Read the fixed metadata prefix of the PKWARE Unix extra field 0x000d.

The fixed portion contains atime, mtime, uid, and gid values. Require
the full 12-byte prefix before reading it, and leave the variable-length
data field unsupported for now.

diff --git a/libarchive/archive_read_support_format_zip.c b/libarchive/archive_read_support_format_zip.c
index 73b8a66408a273d96292fc384ca3165e64f08976..d0afaabc0532007b867489e5f1a996b7701b751e 100644 (file)
--- a/libarchive/archive_read_support_format_zip.c
+++ b/libarchive/archive_read_support_format_zip.c
@@ -756,6 +756,22 @@ process_extra(struct archive_read *a, struct archive_entry *entry,
                         * on which file starts, but we don't handle
                         * multi-volume Zip files. */
                        break;
+               case 0x000d:
+                       /* PKWARE Unix Extra Field fixed metadata. */
+                       if (datasize >= 12) {
+                               zip_entry->atime = archive_le32dec(p + offset);
+                               zip_entry->mtime =
+                                   archive_le32dec(p + offset + 4);
+                               zip_entry->uid =
+                                   archive_le16dec(p + offset + 8);
+                               zip_entry->gid =
+                                   archive_le16dec(p + offset + 10);
+                               /*
+                                * APPNOTE.TXT also defines additional data after
+                                * this fixed metadata, depending on file type.
+                                */
+                       }
+                       break;
 #ifdef DEBUG
                case 0x0017:
                {