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

Launchpad Bug Tracker 1611360 at bugs.launchpad.net
Fri Oct 21 14:08:30 UTC 2016


You have been subscribed to a public bug by Jon Grimm (jgrimm):

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

** Affects: multipath-tools (Ubuntu)
     Importance: High
     Assignee: Jon Grimm (jgrimm)
         Status: Triaged


** Tags: i386 multipath-tools
-- 
Xenial 32-bit: multipath exits with SIGSEGV
https://bugs.launchpad.net/bugs/1611360
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