[Bug 781299] Re: map_block2 triple indirect blocks (segmentation fault)

[Phillip Susi]

*** This bug is a duplicate of bug 899243 ***
    https://bugs.launchpad.net/bugs/899243

** This bug has been marked a duplicate of bug 899243
   [fsck.minix ] segfault while recovering directory with lots  of files

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https://bugs.launchpad.net/bugs/781299

Title:
  map_block2 triple indirect blocks (segmentation fault)

Status in “util-linux” package in Ubuntu:
  New

Bug description:
  Binary package hint: util-linux

  In the function map_block2, in order to check if blknr refers to a
  block pointed by a double indirect pointer, the following comparison
  is made:

  463:  if (blknr >= 256 * 256)   // it should be blknr <= 256 * 256

  However, this is the case for triple indirect blocks. Which means that
  if    blknr <= 256*256, there will be a arithmetic underflow later
  (478: blknr -= 256 * 256) leading to a segmentation fault in the
  check_zone_nr2 function (called from  482: result = check_zone_nr2
  (tind + blknr / (256 * 256), &blk_chg) )

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