Bug 4496

Summary:

[x32] dropbear key generation hangs on x32

Product:

[Build System, Metadata & Runtime] OE-Core

Reporter:

Saul Wold <sgw>

Component:

connectivity

Assignee:

Nitin Kamble <nitin.a.kamble>

Status:

RESOLVED FIXED

QA Contact:

Severity:

major

Priority:

Medium+

CC:

bluelightning, meta.mr.watcher, meta.watcher, nitin.a.kamble, radu.moisan, ross.burton

Version:

1.4.1

Target Milestone:

1.4.1

Hardware:

Other

OS:

x86_64

Whiteboard:

(autobuilder)

OS type for building Yocto:

---

Type of Regression:

---

Verified:

Documentation change:

---

Attachments:

Description	Flags
A patch to fix x32	none

Description Saul Wold 2013-05-15 06:33:10 UTC

dropbear fails to correctly generate a key during startup, it hangs the system.  Initial debug shows that a value passed into the mp_div_3() function is invalid. It should be a reasonable value, but instead is a full 64bit integer. This may be due to the way this number is initially stored.

I did not that the mp_int "used" value is different between x86-64 and x32, the
xa86-64 value was 9 while the x32 value was 19.

Comment 1 Nitin Kamble 2013-05-23 19:46:39 UTC

I tried creating x32 qemux86-64 image. And it built booted fine. Then I tried to run this command: 
  dropbearkey -tdss -f private

and it takes forever to finish it.

Comment 2 H.J. Lu 2013-05-23 21:48:51 UTC

Created attachment 1222 [details]
A patch to fix x32

dropbear should use unsigned long long for unsigned 64-bit
integer.

Comment 3 Nitin Kamble 2013-05-23 22:20:26 UTC

I check the HJ's fix with yocto project. And it does fix the issue I was seeing before. Thanks HJ for the quick fix.

I will cook a commit for posting to YP mailing list.

Nitin

Comment 4 Nitin Kamble 2013-05-30 22:31:07 UTC

Fixed by this commit:

commit 676fd3f394a0c0576b63c77ed2184bf5f42c29b6
Author: Nitin A Kamble <nitin.a.kamble@intel.com>
Date:   Thu May 23 16:09:20 2013 +0000

    dropbear: a fix for hang in dropbearkey, built for x32
    
    This commit fixes runtime hang of 'dropbearkey' utility, built for a x32
    target abi system. The hang was observed while generating ssh keys, with
    this command:
      dropbearkey -t dss -f private
    
    The issue is fixed by changing the code, where 'long' in x86_64 mode is
    assumed as 64bit quantity. With the x32 abi, the processor is in x86_64
    mode, but the 'long' is a 32bit quantity. Hence the fix uses 'long long'
    instead of 'long' to define/access 64bit data variables.
    
    Fixes bug:
    [YOCTO #4496]
    
    (From OE-Core rev: 8f5bc47729edb8cb051d81e9ff1680cb8d2eca25)
    
    Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
    Signed-off-by: Saul Wold <sgw@linux.intel.com>
    Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>