On 02/06/18 20:04, Antonio Diaz Diaz wrote:
Juan Francisco Cantero Hurtado wrote:
I think I have found an unexpected difficulty. It seems that the pax
format has a serious flaw not present in the ustar format. The
extended records in the pax extended header are not protected by any
checksum in spite of containing critical metadata (file size,
filename, file time,...). This may lead to several kinds of undetected
corruption.
You can use a comment entry for the checksum of the headers or whatever
you want. Other tar tools will ignore the entry.
Exactly, *other tar tools will ignore the entry*, leading to a
fragmented format[1] where, depending on how the file was created and on
what unarchiver is used, the integrity check will be sometimes performed
and sometimes not.
[1] http://www.nongnu.org/lzip/xz_inadequate.html#fragmented
Your only options are to create a new format and forget the
compatibility "promise" with existing tools or just live with that
limitation of the posix format.
Anyway, IIUC, the tar headers are inside of the lzip member which checks
the integrity of the content. The risk of corrupted headers is low.
--
Juan Francisco Cantero Hurtado http://juanfra.info
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