tar: do not try to decode GNU extended headers as pax headers

function                                             old     new   delta
get_header_tar                                      1736    1692     -44

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

1 files changed, 17 insertions, 11 deletions

diff --git a/archival/libarchive/get_header_tar.c b/archival/libarchive/get_header_tar.c
index 2dbcdb50c..fb68673b9 100644
--- a/archival/libarchive/get_header_tar.c
+++ b/archival/libarchive/get_header_tar.c
@@ -350,7 +350,14 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
         case '6':
                 file_header->mode |= S_IFIFO;
                 goto size0;
+        case 'g':       /* pax global header */
+        case 'x': {     /* pax extended header */
+                if ((uoff_t)file_header->size > 0xfffff) /* paranoia */
+                        goto skip_ext_hdr;
+                process_pax_hdr(archive_handle, file_header->size, (tar.typeflag == 'g'));
+                goto again_after_align;
 #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+/* See http://www.gnu.org/software/tar/manual/html_node/Extensions.html */
         case 'L':
                 /* free: paranoia: tar with several consecutive longnames */
                 free(p_longname);
@@ -370,18 +377,17 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
                 archive_handle->offset += file_header->size;
                 /* return get_header_tar(archive_handle); */
                 goto again;
-        case 'D':       /* GNU dump dir */
-        case 'M':       /* Continuation of multi volume archive */
-        case 'N':       /* Old GNU for names > 100 characters */
-        case 'S':       /* Sparse file */
-        case 'V':       /* Volume header */
+/*
+ *      case 'S':       // Sparse file
+ * Was seen in the wild. Not supported (yet?).
+ * See https://www.gnu.org/software/tar/manual/html_section/tar_92.html
+ * for the format. (An "Old GNU Format" was seen, not PAX formats).
+ */
+//      case 'D':       /* GNU dump dir */
+//      case 'M':       /* Continuation of multi volume archive */
+//      case 'N':       /* Old GNU for names > 100 characters */
+//      case 'V':       /* Volume header */
 #endif
-        case 'g':       /* pax global header */
-        case 'x': {     /* pax extended header */
-                if ((uoff_t)file_header->size > 0xfffff) /* paranoia */
-                        goto skip_ext_hdr;
-                process_pax_hdr(archive_handle, file_header->size, (tar.typeflag == 'g'));
-                goto again_after_align;
         }
  skip_ext_hdr:
         {