[Bug 1611360] Re: Xenial 32-bit: multipath exits with SIGSEGV

[Jon Grimm]

Hi there Amit!

Yes, I will fix it in xenial & yakkety next.  The Ubuntu development
process requires that it be fixed & vetted in the development release (in
this case 'zesty') first, working on the SRU (Stable Release Update) now.
:)

On Sat, Oct 22, 2016 at 4:10 AM, Amit Oren <aoren at infinidat.com> wrote:

> Thanks Jon Grimm and everyone else, but can you also fix it in Xenial?
> We are using Xenial on our servers as it is LTS, and giving support for
> Xenial to our customers for this very reason, and we did not intend to
> upgrade to Zesty anytime soon. I don't want to use pinning for that
> specific package or any sort of bug-prone solution...
>
> --
> You received this bug notification because you are a bug assignee.
> https://bugs.launchpad.net/bugs/1611360
>
> Title:
>   Xenial 32-bit: multipath exits with SIGSEGV
>
> Status in multipath-tools package in Ubuntu:
>   Fix Released
>
> Bug description:
>   Ubuntu release:
>   Description:  Ubuntu 16.04 LTS
>   Release:      16.04
>
>   Package version: 0.5.0+git1.656f8865-5ubuntu2.1
>
>   The current version of multipath-tools for Xenial
> (0.5.0+git1.656f8865-5ubuntu2.1) causes segmentation fault when trying to
> run, for example, "show paths" from the daemon.
>   When further investigating the issue, it seems that since Ubuntu 14.04,
> the enum describing the keyword type in cli.h is now of size 35. This leads
> to overflows as later on values are left-shifted by the values in these
> enum, and some of those exceed 31 (the maximum legal shift amount in 32-bit
> int).
>   This leads to wrong choice of the handler in the command parsing stage
> (cli.c - find_handler). Specifically in "show paths" it leads to choosing
> cli_list_paths_fmt instead of cli_list_paths, and later to null
> dereferencing and segmentation fault.
>
>   GDB Backtrace:
>   #0  snprint_path_header (line=0xb78010e0 "", len=1200, format=0x0) at
> print.c:795
>   #1  0x08052a6e in show_paths (r=0xb7b52210, len=0xb7b52208,
> vecs=0x809f650, style=0x0, pretty=1) at cli_handlers.c:47
>   #2  0x080532af in cli_list_paths_fmt (v=0xb7800678, reply=0xb7b52210,
> len=0xb7b52208, data=0x809f650) at cli_handlers.c:235
>   #3  0x08052369 in parse_cmd (cmd=0xb7800f68 "show paths",
> reply=0xb7b52210, len=0xb7b52208, data=0x809f650) at cli.c:438
>   #4  0x0804cf49 in uxsock_trigger (str=0xb7800f68 "show paths",
> reply=0xb7b52210, len=0xb7b52208, trigger_data=0x809f650) at main.c:780
>   #5  0x08050e5a in uxsock_listen (uxsock_trigger=0x804cf00
> <uxsock_trigger>, trigger_data=0x809f650) at uxlsnr.c:252
>   #6  0x0804da3b in uxlsnrloop (ap=0x809f650) at main.c:946
>   #7  0xb7fb82b5 in start_thread (arg=0xb7b52b40) at pthread_create.c:333
>   #8  0xb7da216e in clone () at ../sysdeps/unix/sysv/linux/
> i386/clone.S:114
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/multipath-tools/+bug/1611360/+
> subscriptions
>


-- 
Jon Grimm
Engineering Manager, Ubuntu Server
Canonical Ltd

-- 
You received this bug notification because you are a member of Ubuntu
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https://bugs.launchpad.net/bugs/1611360

Title:
  Xenial 32-bit: multipath exits with SIGSEGV

Status in multipath-tools package in Ubuntu:
  Fix Released

Bug description:
  Ubuntu release:
  Description:	Ubuntu 16.04 LTS
  Release:	16.04

  Package version: 0.5.0+git1.656f8865-5ubuntu2.1

  The current version of multipath-tools for Xenial (0.5.0+git1.656f8865-5ubuntu2.1) causes segmentation fault when trying to run, for example, "show paths" from the daemon.
  When further investigating the issue, it seems that since Ubuntu 14.04, the enum describing the keyword type in cli.h is now of size 35. This leads to overflows as later on values are left-shifted by the values in these enum, and some of those exceed 31 (the maximum legal shift amount in 32-bit int).
  This leads to wrong choice of the handler in the command parsing stage (cli.c - find_handler). Specifically in "show paths" it leads to choosing cli_list_paths_fmt instead of cli_list_paths, and later to null dereferencing and segmentation fault.

  GDB Backtrace:
  #0  snprint_path_header (line=0xb78010e0 "", len=1200, format=0x0) at print.c:795
  #1  0x08052a6e in show_paths (r=0xb7b52210, len=0xb7b52208, vecs=0x809f650, style=0x0, pretty=1) at cli_handlers.c:47
  #2  0x080532af in cli_list_paths_fmt (v=0xb7800678, reply=0xb7b52210, len=0xb7b52208, data=0x809f650) at cli_handlers.c:235
  #3  0x08052369 in parse_cmd (cmd=0xb7800f68 "show paths", reply=0xb7b52210, len=0xb7b52208, data=0x809f650) at cli.c:438
  #4  0x0804cf49 in uxsock_trigger (str=0xb7800f68 "show paths", reply=0xb7b52210, len=0xb7b52208, trigger_data=0x809f650) at main.c:780
  #5  0x08050e5a in uxsock_listen (uxsock_trigger=0x804cf00 <uxsock_trigger>, trigger_data=0x809f650) at uxlsnr.c:252
  #6  0x0804da3b in uxlsnrloop (ap=0x809f650) at main.c:946
  #7  0xb7fb82b5 in start_thread (arg=0xb7b52b40) at pthread_create.c:333
  #8  0xb7da216e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:114

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