Bugzilla – Bug 304
Pressing any key after doing 'sudo su -' executes a 'logout'
Last modified: 2009-03-14 08:41:38 MDT
Hello, There's a full description of this bug in this URL: https://bugs.launchpad.net/ubuntu/+source/sudo/+bug/224802 Although I'm not using Ubuntu (I'm using Gentoo), I have the same bug with 'sudo'. My version: Sudo version 1.6.9p16 Thanks.
Can you verify that sudo 1.6.9p17 still exhibits this problem?
(In reply to comment #1) > Can you verify that sudo 1.6.9p17 still exhibits this problem? > Sure, I'll do that :-). Thanks.
(In reply to comment #2) > (In reply to comment #1) > > Can you verify that sudo 1.6.9p17 still exhibits this problem? > > > > Sure, I'll do that :-). Thanks. > Hi Todd, Unfortunately, sudo 1.6.9_p17 still has the problem. Thanks.
There's one interesting thing that I forgot to mention. This problem does NOT occur with the following kernel version: linux-2.6.23-gentoo-r9 Currently, I'm using this kernel version: sergio@miki ~ $ uname -a Linux miki 2.6.25-gentoo-r8 #2 SMP Sun Oct 5 18:03:23 BRT 2008 i686 Genuine Intel(R) CPU T1300 @ 1.66GHz GenuineIntel GNU/Linux Maybe that can help you. Please, let me know if there's something I can do to help you track this issue. Thanks.
Have I read this correctly and the problem only occurs when you do _not_ have to enter a password?
Todd, By default, my sudoers is configured so that I can execute sudo without having to type the password. However, I have temporarily disabled this configuration and done a few tests. As far as I could observe, it seems that the problem doesn't occur when I have to type a password, indeed.
That makes me suspicious that this is actually a PAM-related problem. Can you try running configure with the --disable-pam-session flag and see if the resulting sudo has the same issue. If that's not it then the next thing is to try is to compare the terminal settings of the terminal running "sudo su -" both with an without a password. To do this you'll want two terminal windows. In the first, use the tty command to find the path to the controlling tty. Then run "sudo -k; sudo su -" and enter your password to run su. In the second window, run "stty -a -f "stty -a -f /path/to/tty" where /path/to/tty is the output of the tty command from the first window. Then repeat the process with sudo not prompting you for a password, but be sure to run stty before you press a key (since that would exit the su process). If the terminal settings from stty differ bewteen the two invocations of su, that should help point the way to the actual problem.
Hi all, I'm also don't observe this currently on my Unbutu 8.04 workstation at home, but with pure "su -" (not sudo!) on some of my Gentoo Server's, too. And this type of problem is also reported by users of other distributions! After switching to another user via "su - foo" i eithter get kicked out immediately (the shell writes "exit" or "logout") or just after the first keypress, if this isn't CR. Pressing CR will proceed to the next prompt, any other will act like receiving a SIGHUP from somewhere. Note that the pressed key is displayed before logout. But sometime after leaving the system alone for a while or after rebooting, all will work fine as expected for one try. With the next try, the problem occurs again. And more, sometime it will work with user account a, but not with b and othertimes vice versa. In addition, one of two nominal nearly-cloned boxes of one of my clusters show the problem, the other one works flawless. Some other guys wrote, that this only will happen with bash -- i don't check it. But i don't think it's realy related to bash, su or sudo in core. I also try to get a hint from 'strace su - foo'. But using this type of invocation, everythink works well, again! From this, i think it's some very strange kind of a race condition. Maybe on slow hardware, maybe just -- as another one reports -- on *single* (non-HT) CPU systems. I observe it on my test boxes, which holds simple 1.6GHz P4 boards. I get notice of this problems about two weeks after a general update of this Gentoo systems, pulling it from a software release time somewhere in 2007 (e.g. kernel 2.6.21) to our days (with a "conservative" kernel 2.6.25). One of the test boxes is still at 2.6.21, but have newer packages of other software already applied. This box seems to work fine, so maybe it's related to some kernel changes far back in time.
Tom, This bug also happens to me and I have the results of the stty test as described in comment #6 file #1 is results of running stty -a -F /dev/pts/2 >1 after using sudo with a password. file #2 is without a password and without pressing a key (so it didn't kick me out) diff 1 2 6,7c6,7 < -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl ixon -ixoff < -iuclc -ixany -imaxbel iutf8 --- > -ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl ixon -ixoff > -iuclc -ixany imaxbel iutf8
Created attachment 250 [details] diff to flush tty before executing command
Can you give the diff I just attached a try? It really shouldn't make any difference but it's worth a shot.
(In reply to comment #11) > Can you give the diff I just attached a try? It really shouldn't make > any difference but it's worth a shot. Updated to sudo 1.7.0 and applied the patch. The patch did not fix the problem. Also tried compiling without pam support, but that didn't help either.
(In reply to comment #12) > (In reply to comment #11) > > Can you give the diff I just attached a try? It really shouldn't make > > any difference but it's worth a shot. > > Updated to sudo 1.7.0 and applied the patch. > > The patch did not fix the problem. > Also tried compiling without pam support, but that didn't help either. > Some more testing seems to indicate that sudo is not the source of the bug. As root a "su $some_other_name" shows the same problem. Any thoughts on where to look next? Just updated core-utils to the latest version, but the problem remains. -james
Seems like it has to either be a kernel or bash bug. See the links in the ubuntu bug report listed in the description of this bug.
(In reply to comment #14) > Seems like it has to either be a kernel or bash bug. See the links in > the ubuntu bug report listed in the description of this bug. > Todd, Update: Core-utils 6.12 seems to work for me, as does an unpatched 7.1 version. My initial update of coreutils was using the binary package that my distro provided. However this version includes a PAM patch from Fedora that triggers this problem. If the pkg is rebuilt without that PAM patch it works as expected. If it's rebuilt with the patch then this annoying su bug shows up. Thank you for your help on this. -james
(In reply to comment #14) > Seems like it has to either be a kernel or bash bug. See the links in > the ubuntu bug report listed in the description of this bug. > For me, the problem have gone with applying some general Gentoo updates to my bunch of (different) boxes in the first two month of 2009. But this neither include a kernel update, not even coreutils or pam. But e.g. bash and cracklib was refreshed. As if the problem appears before, I have no idea what concrete package update now is "responsible" for fixing the problem. My current version of coreutils is gentoo's 6.10-r2, last build here eg. at 2008-05-13. bash is at 3.2._p39, build here in 2009-01.
Closing, as this is not a sudo problem.