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Re: Process substitution can leak CTLESC (0x01) in output
From: |
Chet Ramey |
Subject: |
Re: Process substitution can leak CTLESC (0x01) in output |
Date: |
Fri, 17 Feb 2017 11:34:44 -0500 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 |
On 2/16/17 3:36 PM, David Simmons wrote:
> [ Re-sending... it doesn't look like this went through the first time. ]
>
> Bash uses 0x01 (CTLESC) and 0x7F (CTLNUL) bytes within command word strings
> that are passed around internally. If either of these bytes appear in the
> parser input, they are escaped with an extra 0x01 (CTLESC), but such
> escaping is reverted before final use.
>
> When I use ANSI-C quoting to represent these bytes in a process
> substitution context, they appear to be CTLESC-encoded twice in their
> journey through bash. For example, 7F becomes 01 7F which becomes 01 01 01
> 7F, then decoded once as 01 7F before final use. This leads to spurious
> 0x01 bytes.
Thanks for the report. This exists as far back as bash-2.05b, and probably
dates from the initial process substitution implementation in the early
1990s.
It will be fixed in the next release of bash.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/