Ok, the issue seems to be related to the locale in use. Namely this seems to be happening when using Italian locale (possibly other locales will be affected as well), where commas (as opposed to dots) are used to separate the decimal part of a figure.
Booting the ISOs of Trusty / Unity, Wily / Unity and Wily / GNOME choosing Italian as the language the issue is always present, while booting choosing English as the language the issue is never present. So to reproduce: simply boot one of the Trusty / Unity, Wily / Unity or Wily / GNOME ISOs (most likely all other ISOs will be affected as well) choosing Italian as the language, open Terminal, run sudo visudo, add a line "Defaults timestamp_timeout=2.5", save, exit and try to run a sudo command (e.g. sudo -l). ** Description changed: % lsb_release -rd Description: Ubuntu 15.10 Release: 15.10 % apt-cache policy sudo sudo: Installed: 1.8.12-1ubuntu3 Candidate: 1.8.12-1ubuntu3 Version table: *** 1.8.12-1ubuntu3 0 500 http://archive.ubuntu.com/ubuntu/ wily/main amd64 Packages 100 /var/lib/dpkg/status --- - Setting a number with a fractional part as the value to the + When using Italian locale (possibly other locale will be affected as + well), setting a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers makes sudo complain about it, not honor the desired timeout and behave as if timestamp_timeout wasn't set at all: after the expiration of the first timestamp sudo stops complaining about it, but the desired timeout is still not honored. % sudo sleep 1 sudo: value `2.5' is invalid for option `timestamp_timeout' % sudo -l sudo: value `2.5' is invalid for option `timestamp_timeout' Matching Defaults entries for user on user-X550CL: env_reset, timestamp_timeout=2.5, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin User user may run the following commands on user-X550CL: (ALL : ALL) ALL ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: sudo 1.8.12-1ubuntu3 ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3 Uname: Linux 4.2.0-16-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: GNOME Date: Sat Mar 26 23:36:41 2016 InstallationDate: Installed on 2016-02-16 (39 days ago) InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021) ProcEnviron: TERM=xterm-256color PATH=(custom, no username) XDG_RUNTIME_DIR=<set> LANG=it_IT.UTF-8 SHELL=/usr/bin/zsh SourcePackage: sudo UpgradeStatus: No upgrade log present (probably fresh install) VisudoCheck: /etc/sudoers: parsed OK /etc/sudoers.d/README: parsed OK modified.conffile..etc.sudoers: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers'] modified.conffile..etc.sudoers.d.README: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/README'] ** Description changed: % lsb_release -rd Description: Ubuntu 15.10 Release: 15.10 % apt-cache policy sudo sudo: Installed: 1.8.12-1ubuntu3 Candidate: 1.8.12-1ubuntu3 Version table: *** 1.8.12-1ubuntu3 0 500 http://archive.ubuntu.com/ubuntu/ wily/main amd64 Packages 100 /var/lib/dpkg/status --- - When using Italian locale (possibly other locale will be affected as + When using Italian locale (possibly other locales will be affected as well), setting a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers makes sudo complain about it, not honor the desired timeout and behave as if timestamp_timeout wasn't set at all: after the expiration of the first timestamp sudo stops complaining about it, but the desired timeout is still not honored. % sudo sleep 1 sudo: value `2.5' is invalid for option `timestamp_timeout' % sudo -l sudo: value `2.5' is invalid for option `timestamp_timeout' Matching Defaults entries for user on user-X550CL: env_reset, timestamp_timeout=2.5, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin User user may run the following commands on user-X550CL: (ALL : ALL) ALL ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: sudo 1.8.12-1ubuntu3 ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3 Uname: Linux 4.2.0-16-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: GNOME Date: Sat Mar 26 23:36:41 2016 InstallationDate: Installed on 2016-02-16 (39 days ago) InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021) ProcEnviron: TERM=xterm-256color PATH=(custom, no username) XDG_RUNTIME_DIR=<set> LANG=it_IT.UTF-8 SHELL=/usr/bin/zsh SourcePackage: sudo UpgradeStatus: No upgrade log present (probably fresh install) VisudoCheck: /etc/sudoers: parsed OK /etc/sudoers.d/README: parsed OK modified.conffile..etc.sudoers: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers'] modified.conffile..etc.sudoers.d.README: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/README'] ** Summary changed: - Unable to set a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers + Unable to set a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers when using Italian locale (possibly other locales will be affected as well) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to sudo in Ubuntu. https://bugs.launchpad.net/bugs/1562419 Title: Unable to set a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers when using Italian locale (possibly other locales will be affected as well) Status in sudo package in Ubuntu: New Bug description: % lsb_release -rd Description: Ubuntu 15.10 Release: 15.10 % apt-cache policy sudo sudo: Installed: 1.8.12-1ubuntu3 Candidate: 1.8.12-1ubuntu3 Version table: *** 1.8.12-1ubuntu3 0 500 http://archive.ubuntu.com/ubuntu/ wily/main amd64 Packages 100 /var/lib/dpkg/status --- When using Italian locale (possibly other locales will be affected as well), setting a number with a fractional part as the value to the timestamp_timeout option in /etc/sudoers makes sudo complain about it, not honor the desired timeout and behave as if timestamp_timeout wasn't set at all: after the expiration of the first timestamp sudo stops complaining about it, but the desired timeout is still not honored. % sudo sleep 1 sudo: value `2.5' is invalid for option `timestamp_timeout' % sudo -l sudo: value `2.5' is invalid for option `timestamp_timeout' Matching Defaults entries for user on user-X550CL: env_reset, timestamp_timeout=2.5, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin User user may run the following commands on user-X550CL: (ALL : ALL) ALL ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: sudo 1.8.12-1ubuntu3 ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3 Uname: Linux 4.2.0-16-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: GNOME Date: Sat Mar 26 23:36:41 2016 InstallationDate: Installed on 2016-02-16 (39 days ago) InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021) ProcEnviron: TERM=xterm-256color PATH=(custom, no username) XDG_RUNTIME_DIR=<set> LANG=it_IT.UTF-8 SHELL=/usr/bin/zsh SourcePackage: sudo UpgradeStatus: No upgrade log present (probably fresh install) VisudoCheck: /etc/sudoers: parsed OK /etc/sudoers.d/README: parsed OK modified.conffile..etc.sudoers: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers'] modified.conffile..etc.sudoers.d.README: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/README'] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/sudo/+bug/1562419/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
