Public bug reported:
When calling lb_config with parameters like `--iso-volume`, the length
of the string is not correctly determined. The argument in the following
example is limited to 32 characters, but the code in
`/usr/share/live/build/functions/defaults.sh` only allows 31 characters:
# trying with 33 characters -> fails as expected
root@53e16c910d1d:/tmp# lb config --iso-volume
'123456789-123456789-123456789-123'
[2016-03-16 15:21:05] lb_config --iso-volume 123456789-123456789-123456789-123
P: Considering defaults defined in /etc/live/build.conf
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
P: Updating config tree for a ubuntu/amd64 system
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
# trying with 32 characters -> fails but should work
root@53e16c910d1d:/tmp# lb config --iso-volume
'123456789-123456789-123456789-12'
[2016-03-16 15:21:07] lb_config --iso-volume 123456789-123456789-123456789-12
P: Considering defaults defined in /etc/live/build.conf
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
P: Updating config tree for a ubuntu/amd64 system
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
# trying with 31 characters -> works as expected
root@53e16c910d1d:/tmp# lb config --iso-volume '123456789-123456789-123456789-1'
[2016-03-16 15:21:09] lb_config --iso-volume 123456789-123456789-123456789-1
P: Considering defaults defined in /etc/live/build.conf
P: Updating config tree for a ubuntu/amd64 system
There are two reasons for this error:
* The string is sent to `wc -c` using `echo` which adds an extra line end
character to the string
* three of four tests surround their string by escaped " characters which are
also counted. For LB_ISO_VOLUME, the developer tried to fix this using the
`eval` function
Additionally, the code is unnecessarily complex. Both dash and bash
provide the `$#variable` syntax for getting the string length
I add two patches, one fixes the problem and the second one contains the
(simpler) alternative alternative syntax which works similar.
Tested with live-build from 3.0~a57-1ubuntu22 from ubuntu wily but the
current 3.0~a57-1ubuntu25 from xenial contains the same code
root@53e16c910d1d:/# dpkg -l live-build
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version
Architecture Description
+++-===========================================================-==================================-==================================-===========================================================================================================================
ii live-build
3.0~a57-1ubuntu22 all Debian
Live - System build scripts
root@53e16c910d1d:/# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 15.10
Release: 15.10
Codename: wily
Console output of patched code (both variants):
root@53e16c910d1d:/tmp# lb config --iso-volume
'123456789-123456789-123456789-123'
[2016-03-16 15:20:26] lb_config --iso-volume 123456789-123456789-123456789-123
P: Considering defaults defined in /etc/live/build.conf
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
P: Updating config tree for a ubuntu/amd64 system
W: You have specified a value of LB_ISO_VOLUME that is too long; the maximum
length is 32 characters.
root@53e16c910d1d:/tmp# lb config --iso-volume
'123456789-123456789-123456789-12'
[2016-03-16 15:20:29] lb_config --iso-volume 123456789-123456789-123456789-12
P: Considering defaults defined in /etc/live/build.conf
P: Updating config tree for a ubuntu/amd64 system
** Affects: live-build (Ubuntu)
Importance: Undecided
Status: New
** Patch added: "variant1.patch"
https://bugs.launchpad.net/bugs/1558109/+attachment/4601168/+files/variant1.patch
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https://bugs.launchpad.net/bugs/1558109
Title:
Incorrect calculation of string lengths
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