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Re: [Bug-xorriso] Crash in xorriso with fix


From: Thomas Schmitt
Subject: Re: [Bug-xorriso] Crash in xorriso with fix
Date: Thu, 25 Jul 2019 11:25:11 +0200

Hi,

Eliska Svobodova wrote:
> Sorry about test ACL, I haven't work with it
> before and only focused on causing the segfault.

Insofar your script was very successful.

The following modified loop produces valid ACL entry texts

  for i in {1..10000}; do echo user:$i:rwx >> File_with_users; done

These entries can be read by xorriso's -sefacl* commands, because like
with setfacl(1) number texts are interpreted as uid numbers.
(libisofs does this if the text is not found as user name. I am currently
 not aware what setfacl(1) would do if user "123" has uid 1000.)

Processing time of the -setacl_list command is about 5 seconds on 3.5 GHz
Xeon. So it looks like the effectivity of libisofs' ACL processing with
large lists could be improved.

I produced an ISO image with the generously sized ACL by

  valgrind --leak-check=full \
    xorriso -for_backup \
            -outdev test.iso \
            -map . / \
            -setfacl_list File_with_users

and then inspected it sucessfully by

  xorriso -for_backup -indev test.iso -getfacl_r / -- 2>&1 | less

But i did not dare to restore Test_file to my hard disk. Not a bit curious
to learn about potential bugs in ext4.

Command -for_backup implies -acl "on". Without that setting ACL are neither
stored, nor read-in, nor extracted by -osirrox "on" -extract / ./Text_dir_X


Have a nice day :)

Thomas




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