Bug 184357

Summary: buffer_append_space: alloc not supported Error
Product: Red Hat Enterprise Linux 4 Reporter: Cove Schneider <cove>
Component: opensshAssignee: Tomas Mraz <tmraz>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: cove
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: RHSA-2007-0257 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-05-01 17:29:29 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Attachments:
Description Flags
Patch against openssh-4.3p2 that appears to fix the problem
none
Kit to reproduce the problem none

Description Cove Schneider 2006-03-08 07:13:04 UTC 
Description of problem:

Sshd fails if remote program generates too much output when using v2. It looks
like the code to throttle the stdout from the program being executed is
commented out in v2. So the sshd continues to allocate memory to buffer the
stdout until it hits aprox 10Mb and then it just aborts. This doesn't happen
with openssh's own client, possibly due to it's constant adjustments to the
window sizes works around it.

Version-Release number of selected component (if applicable):

All OpenSSH v2 versions at this point.

How reproducible:

Always.

Steps to Reproduce:
[see attachment]
1. Download cryptlib from http://www.cs.auckland.ac.nz/~pgut001/cryptlib/
2. Replace session/ssh2_msg.c and session/ssh2_rw.c with the ones included in
this tar file.
3. Compile cryptlib
4. Edit sshtest.c and put in your account settings and the path to the genstdout
binary
5. Compile genstdout and sshtest (see compile.sh)
6. Run sshtest
 
Actual results:

In the sshd logs you'll find:
fatal: buffer_append_space: alloc 10489856 not supported

Expected results:

The program should just continue to run until interrupted.

Additional info:
Comment 1 Cove Schneider 2006-03-08 07:13:04 UTC 
Created attachment 125784 [details]
Patch against openssh-4.3p2 that appears to fix the problem
Comment 2 Cove Schneider 2006-03-08 07:17:06 UTC 
Created attachment 125785 [details]
Kit to reproduce the problem
Comment 4 Tomas Mraz 2006-04-04 15:08:12 UTC 
It seems there is now a real patch in the upstream bugzilla.
http://bugzilla.mindrot.org/show_bug.cgi?id=1131
Comment 5 Cove Schneider 2006-04-05 20:59:18 UTC 
Latest patch works for me.

http://bugzilla.mindrot.org/attachment.cgi?id=1117
Comment 6 RHEL Program Management 2006-08-31 15:33:36 UTC 
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.
Comment 8 Tomas Mraz 2006-10-05 08:52:21 UTC 
Fixed in openssh-3.9p1-8.RHEL4.18
Comment 12 Red Hat Bugzilla 2007-05-01 17:29:29 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2007-0257.html