Check for backward-pointing directory entries to avoid endless looping

Signed-off-by: John W. Linville <[email protected]>
linvjw · Apr 8, 2015 · 7c9a650 · 7c9a650
1 parent 35d7d76
commit 7c9a650
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/unzoo.c b/unzoo.c
@@ -2405,9 +2405,11 @@ int ListArch ( ver, arc, filec, files )
  /* loop over the members of the archive */
  Entry.posnxt = Descript.posent;
  while ( 1 ) {
+ unsigned long oldpos = Entry.posnxt;
 
  /* read the directory entry for the next member */
- if ( ! GotoReadArch( Entry.posnxt ) || ! EntrReadArch() ) {
+ if ( ! GotoReadArch( Entry.posnxt ) || ! EntrReadArch() ||
+ Entry.posnxt <= oldpos ) {
  printf("unzoo: found bad directory entry in archive '%s'\n",arc);
  return 0;
  }
@@ -2561,9 +2563,11 @@ int ExtrArch ( bim, out, ovr, pre, arc, filec, files )
  /* loop over the members of the archive */
  Entry.posnxt = Descript.posent;
  while ( 1 ) {
+ unsigned long oldpos = Entry.posnxt;
 
  /* read the directory entry for the next member */
- if ( ! GotoReadArch( Entry.posnxt ) || ! EntrReadArch() ) {
+ if ( ! GotoReadArch( Entry.posnxt ) || ! EntrReadArch() ||
+ Entry.posnxt <= oldpos ) {
  printf("unzoo: found bad directory entry in archive '%s'\n",arc);
  return 0;
  }