Fedora Security :: SELinux Blocking Sshd Access To Shadow?
Mar 6, 2010
I'm trying to setup ssh access on my Fedora 12 laptop. I get the following error message in /var/log/secure when I try to login from another machine using ssh and the login is denied:
Code:
sshd[3025]: error: Could not get shadow information for <user>
sshd[3025]: Failed password for <user> from <ip> port <port> ssh2
If I do a 'setenforce 0' I can login and no error is logged.
Tried google and searching this forum to no avail. Under Fedora 14, there is an selinux policy which blocks sshd from making outbound connections on port 80 or 443. This can occur when a client box tries to tunnel through the ssh connection for encrypted access to the web.
While I did manage to allow this happen by creating a permissive domain for sshd with this command:
Code:
The preferred way would be to allow sshd to make connection on other ports with a similar command that does not seem to work:
Code:
Is this the correct way of allowing an outbound port connection for the sshd daemon?
I am running Fedora 11 and every time i plug in my iPod it tells me... SELinux is preventing mkdir (podsleuth_t) "read" security_t ... I have no idea on how to create a policy module to allow access.
When I turn on my SeLinux to enforcing mode on my Red Hat system ssh stops working and my http server stops responding.
I went into the SeLinux GUI and enabled things in there but still it wont work.
Any thoughts on what to check?
permissive mode and disabled they work
I read several articles that say it should not be affect by SeLinux and the setting look correct but the only thing I do is turn on SeLinux and ssh /httpd stop working
I went to print something and I get this message: Summary: SELinux is preventing access to files with the default label, default_t.
Detailed Description: SELinux permission checks on files labeled default_t are being denied. These files/directories have the default label on them. This can indicate a labeling problem, especially if the files being referred to are not top level directories. Any files/directories under standard system directories, /usr, /var. /dev, /tmp, ..., should not be labeled with the default label. The default label is for files/directories which do not have a label on a parent directory. So if you create a new directory in / you might legitimately get this label.
Quick explanation about what this thread is: by way of an article featured on linuxtoday, I learned about what appears to be an actively managed IP blacklist: [URL]
# This is a compiled list of dirty hosts associated with # bruteforcing attempts, spam, botnets, RBN and the list # continues to grow. The data is comprised of information # compiled from Arbor Networks, Project Honeypot, FIRE # (maliciousnetwork.org), Host Exploit, Shadowserver and # a variety of other similarly based sites.
Quick explanation about what this thread is not: this is not intended to be a discussion about default deny vs. default allow (i.e. whitelists vs. blacklists), nor is this a call for enumerations of your own sshd hardening strategy. Please try to keep on point. That said, can anyone speak to the quality of the blacklist information noted above? And/or are there any suggestions for a readily available blacklist of "known better" quality? I plan to try including an actively maintained blacklist like this into a multi-layered approach for hardening an sshd bastion host.
I'd like to grant /usr/sbin/sendmail.sendmail "connectto" access to the unix_stream_socket /var/lib/imap/socket/lmtp.How do I do that?I want to eliminate error messages that keep appearing in my message log:
/var/log/messages:Jan 13 11:45:29 e setroubleshoot: SELinux is preventing /usr/sbin/sendmail.sendmail from connectto access on the unix_stream_socket /var/lib/imap/socket/lmtp. For complete SELinux messages. run sealert -l 05df828f-4402-
I'm running a program called Synergy+ to let my keyboard and mouse control multiple computers. One of Synergy+'s features is that clipboard (copy-paste) data is able to be shared, as in copy on one machine, paste onto another. I would like this functionality removed but Synergy+ has no way to disable it. I'm looking for any ideas to block clipboard data from being transferred. Is there a way to block a program from accessing the machine's clipboard data?
I'v just installed wicd. I can't get it to sart, I get errors saying that wicd couldn't connect to it's dbus interface and the wicd deamon has shut down. Then there's a report from SELinux saying that it's preventing /usr/bin/python "write" access on /etc/dhcp/manager-settings.conf and that access is denied to wicd. I can get wicd to start if I su to root, but I'd like to not have to do that every time I boot. Is there a fix?
this is the allert i got:Code:Summary:Your system may be seriously compromised! /usr/sbin/NetworkManager tried to loada kernel module.Detailed Description:SELinux has prevented NetworkManager from loading a kernel module. All confinedprograms that need to load kernel modules should have already had policy writtenfor them. If a compromised application tries to modify the kernel this AVC willbe generated. This is a serious issue.Your system may very well be compromised.Allowing Access:Contact your security administrator and report this issue.Additional Information:
This is weird, today I updated my system and while trying to visudo from single user mode got
"cannot read /etc/shadow: Permission denied"
which kept me from doing anything until I switched to file permissions of 400 on shadow, then back. Is this being experienced by anyone else or just me? /etc/security/limits.conf doesn't seem like it wants to change in enforcing mode either and I can't find any alerts to provide clues on the situation.
I want to enable sshd from Internet, but I want to secure it as much as possible.Therefore, despite the fact that the service will run on a tcp port above 2000 to prevent most scans, I would like to :- First, force the use of a client certificate, to avoid brute force attack on my users/passwords- second force the use of a username/password to avoid someone having access to my system just by stealing my key..When I look at the configuration, it's possible to enable both, but one of them is sufficient to login, but I can't find how to make them both mandatory...
Now I know that the first is the tunnel end but how can I connect the two lines if I don't know the port number (ie: someone else estabilieshes another tunnel)
I've been trying to write php or perl code to generate the sha-512 password hashes in fedora. I've been unable to do the hashing which is encoded in the shadow file on fedora core 11. Does anyone have php or perl code which provides the hashing algorithm. (All of my attempts result in the encrypted hashing being longer than 86 character -- the length that crypt says the sha-512 should be)
I'm attempting to get MapServer running on my Fedora 13 computer. I was able to install with the package manager, and the executable (mapserv) was originally placed in /usr/sbin. But I need it in /var/www/cgi-bin to work on the webserver. So I copied the file to the right location. Unfortunately, it doesn't have the correct SELinux context. Here's the message from the troubleshooter:
SELinux denied access requested by /var/www/cgi-bin/mapserv. /var/www/cgi-bin/mapserv is mislabeled. /var/www/cgi-bin/mapserv default type is httpd_sys_script_exec_t, but its current type is httpd_sys_script_exec_t. Changing this file back to the default type, may fix your problem.
How's that for circular logic? Does anyone have an idea what the correct SELinux context for a cgi-bin executable might be?
Trying to keep selinux enabled. When I start SeLinux Troubleshooter from the menu, which is inautostart as well, It tells me SELinux not enabled, sealert will not run on nonSELinus systems".How do I get SELinux permanently started then
My newly installed Fedora-14 (64-bit) has SELinux disabled. I can't find any way to enable it. I tried to set it manually in /etc/selinux/config to enforcing or permissive but nothing happens after reboot. In GUI configuration tool it is set to disabled and grayed out so that there is no way to enable it there. Is there another way to enable SELinux?
I tried to log in to my xguest account and it asked for a password, which it shouldn't, so there's a problem with SELinux.When I type getenforce it says it is disabled, yet when I go to /etc/selinux and look at the config, it is in enforcing mode and not commented out, type is strict.When I go to the SELinux management GUI I can't change the current enforcing mode and it's set to disabled and default to enforcing.
I want to ask about securing the FTP connection... I have one server that Installed with Redhat Linux Fedora 6.
And now, i want to securing the FTP access, so only the selected IP will be allowed to connect. Do anyone know how to do this?
Another thing is, my server using Webmin 1.3 to manage the server and there not installed / not configured yet with Frox FTP, ProFTPD Server, WU-FTP Server... even there is such thing in my Webmin...
Can i make use one of the three FTP i mention above, and if yes, will it be affecting the current FTP access?
I'm assuming that the following should block the complete 178.123.xxx.xxx address range.
Code: iptables -I INPUT -s 178.123.0.0/24 -j DROP Then I believe that I need to save this change.
Code: service iptables save iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]
However, I'm not so sure that it is actually working based on the fact that there continues to be access to my wiki from that address range. The following is after I made the firewall change.
Quote:
178.123.177.61 - - [31/Dec/2010:04:24:40 -0500] "GET /mywiki/Opera%20Web%20Browser?action=edit&editor=text HTTP/1.1" 200 6346 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)" code....
Let me state that I'm new at this iptables thing. I did some reading and decided that I need to make the above change to the firewall but it doesn't seem to make a difference.
since I upgraded to F15 I noticed that "su -l" is very slow, it takes about 20sec before it gives the prompt. I traced it down to a problem with "xauth" as su asks for the authorization for the display running "xauth nlist :0" which times out with an error. Actually, the command "xauth nlist :0" by itself gives: xauth: timeout in locking authority file /home/user/.kde/tmp-host.domain/xauth-200-_0
If I put SELinux in permissive mode both command work without problem so I suppose SEL is the problem. I checked the permissions and settings of the file which is "unconfined_u:object_r:config_home_t:s0" but I have no idea if this is the right value, running "restorecon" on the file, directory or the whole /home/user didn't change anything.
I get a SELinux relabel often even without changing stuff. SELinux troubleshoot doesn't show any error nor are there any messages in /log/messages that give any clue. Where should I look to see whats happening ?
I wonder if SELinux really are necessary for a home desktop ? It only makes my computer use more problematic than it already is. What can happend if I uninstall it on my Fedora 13 dist ? Is the hole Internet going to come in to my computer and destroy it ?
If I uninstall SELinux, is the firewall uninstalled also ?
I have recently upgraded from FC12 to FC13, and last week I updated all packages using YUM. The system is running as a VM inside CentOS 5.5 using KVM. SELinux is enforcing, using the targeted policy. Bugzilla is version 3.6.1 and was NOT installed using RPM or YUM.
Bugzilla was working OK on this machine until SELinux was upgraded last week from 3.7.19-28 to 3.7.19-33, and is still broken after testing 3.7.19-37 from the testing repo. With SELinux in enforcing mode, apache returns error 500 when I browse to the main bugzilla page. The apache error log shows this:-
Code: [Mon Jul 19 13:15:08 2010] [error] [client 192.168.40.1] (13)Permission denied: exec of '/var/www/html/bugzilla/index.cgi' failed Nothing, and I mean absolutely nothing, is recorded in /var/log/audit/audit.log, /var/log/messages or /var/log/secure.