1058972 – pinentry-curses mixes control pipe and TTY in non-interactive setups

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Bug 1058972 - pinentry-curses mixes control pipe and TTY in non-interactive setups

Summary: pinentry-curses mixes control pipe and TTY in non-interactive setups

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	pinentry
Sub Component:
Version:	7.0
Hardware:	Unspecified
OS:	Unspecified
Priority:	medium
Severity:	medium
Target Milestone:	rc
Target Release:	7.1
Assignee:	Boris Ranto
QA Contact:	Karel Srot
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:	1289025 1305230
TreeView+	depends on / blocked

Reported:	2014-01-28 21:59 UTC by Miloslav Trmač
Modified:	2016-11-04 01:04 UTC (History)
CC List:	3 users (show)
Fixed In Version:	pinentry-0.8.1-16.el7 pinentry-0.8.1-17.el7
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2016-11-04 01:04:43 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)
proposed patch (1.15 KB, patch) 2014-02-14 12:03 UTC, Stanislav Ochotnicky	no flags	Details \| Diff
View All

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2016:2226	0	normal	SHIPPED_LIVE	pinentry bug fix and enhancement update	2016-11-03 13:26:31 UTC

Description Miloslav Trmač 2014-01-28 21:59:39 UTC

Version-Release number of selected component (if applicable):
pinentry-0.8.1-12.el7.x86_64

Steps to Reproduce:
$ (echo 'GETPIN'; sleep 3600) | pinentry-curses |& cat -v

Actual results:
See an "OK your orders please line, followed by terminal control sequences

Expected results:
See no control sequences sent to the control pipe, and fail cleanly.


This seems to be the underlying cause of the breakage in non-interactive setups.  Ordinarily gpg-agent sends "OPTION ttyname" to a TTY to be used, but that AFAICS only happens if one of the standard file descriptors is a TTY; if it isn't (e.g. during a mock build), no OPTION ttyname is used, and pinentry defaults to using stdin/stdout - both writing escape sequences where the agent is expecting a response, and waiting for the PIN input from the agent's command input.

The same problem happens for pinentry-gtk2 when it falls back to the curses backend.


The full reproducer mirroring a non-interactive situation, starting e.g. from a terminal in X:
$ pkill gpg
$ rm ~/.gnupg/S.gpg-agent
$ GPG_AGENT_INFO= DISPLAY= gpg2 -c -o test </dev/null 2>&1 |cat
# ... will hang, with pinentry-* actually taking 100% CPU because read(0) returns "0" and pinentry doesn't interpret this as a reason to give up.

Comment 3 Stanislav Ochotnicky 2014-02-14 12:03:43 UTC

Created attachment 863242 [details]
proposed patch

I have sent attached patch to upstream, however I am not 100% sure about this. Pinentry has quite a few interactions around assuan protocol and it's entirely possible the patch would break some of those use cases. Otherwise I am not sure why wouldn't upstream do this change long time ago.

Comment 7 RHEL Program Management 2014-03-22 06:08:19 UTC

This request was not resolved in time for the current release.
Red Hat invites you to ask your support representative to
propose this request, if still desired, for consideration in
the next release of Red Hat Enterprise Linux.

Comment 8 Boris Ranto 2015-08-27 15:21:23 UTC

The patch is available upstream

http://git.gnupg.org/cgi-bin/gitweb.cgi?p=pinentry.git;a=commit;h=3803fd15942f2f25108e400be6cd6faef791c8f7

and is fairly straight-forward. We should aim this bz at 7.3. (fasttrack should be ok)

Comment 19 errata-xmlrpc 2016-11-04 01:04:43 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2226.html

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