Can't su to root, after issuing chmod -s /bin/su
When I try to issue "su -", I get "su: Authentication failure", and I'm 100% sure password I enter is ok.
I think it started to happen after I issued chmod +s /usr/bin/screen chmod 755 /usr/bin/screen which I believe is unrelated to this problem, and, chmod -s /bin/su (-s by mistake) chmod 755 /bin/su which most probably made the whole mess... this is not the part of the problem I believe but here's some background why I did that... when trying to make possible for screen sessions to be started automatically on boot under non-root account, I entered something like "su - username -c "/usr/bin/screen -dmS screenname ./executable-file"" in bootmisc.sh, but I was getting "must run suid root for multiuser support", so I tried to fix it, and now I can't login to root account no way :( Is there any way to heal the situation? |
Hi,
It looks like the permissions on /bin/su are not correct, which you did yourself with the chmod 755 /bin/su statement. Restore the original permissions (as root): Code:
chmod 4755 /bin/su -rwsr-xr-x 1 root root 34024 Feb 11 21:54 /bin/su instead of -rwxr-xr-x 1 root root 32024 Feb 11 21:54 /bin/su Hope this helps. |
Thanks, I guess I must do it from some live bootable CD? My current user is not privileged enough for chmod 4777 /bin/su ..
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Hi,
Using a live cd should work. |
Thanks for feedback, it's solved now...
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How do you login? You could have used "CTRL-ALT-F1" to get a text screen and login there as root when you have a GUI with automatic login to your user account by default. Back with "ALT-F7".
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