Re: SELinux Apache and Symbolic Links...GGGrrrr

[Dominick Grift]

On Mon, Apr 19, 2010 at 05:53:19PM -0500, Serge E. Hallyn wrote:
>  Quoting Another Sillyname (anothersname(a)googlemail.com):
>  >  Hi All
>  > 
>  > OK I've been playing with this for nearly two days now and cannot seem
>  > to get it working at all.
>  > 
>  > In a nutshell.
>  > 
>  > Standard Apache Server setup...
>  > 
>  > in /var/www/html I have a subdirectory called reststop and within that
>  > is a symbolic link to a directory at
>  > /mnt/anotherdrive/newpath/nearlythere/reststop
>  > 
>  > I have set the permissions chcon -R 775 /var/www/html/reststop
>  > I have set the permissions chcon -R 775
>  > /mnt/anotherdrive/newpath/nearlythere/reststop
>  > 
>  > I have set the se permissions chcon -R -h -t httpd_sys_content_t
>  > /var/www/html/reststop
>  > I have set the se permissions chcon -R -h -t httpd_sys_content_t
>  > /mnt/anotherdrive/newpath/nearlythere/reststop
>  > 
>  > I have checked the settings using ls -Z and they are correct
>  > 
>  > I have set the http.conf to allow followsymlinks
>  > 
>  > If I set selinux to permissive I DO get an error message:-
>  > 
>  > ------------------------------------------------------------
>  > 
>  > Summary:
>  > 
>  > SELinux is preventing access to files with the label, file_t.
>  > 
>  > Detailed Description:
>  > 
>  > [SELinux is in permissive mode. This access was not denied.]
>  > 
>  > SELinux permission checks on files labeled file_t are being denied. file_t is
>  > the context the SELinux kernel gives to files that do not have a label. This
>  > indicates a serious labeling problem. No files on an SELinux box should ever be
>  > labeled file_t. If you have just added a disk drive to the system you can
>  > relabel it using the restorecon command. For example if you saved the home
>  > directory from a previous installation that did not use SELinux, 'restorecon -R
>  > -v /home' will fix the labels. Otherwise you should relabel the entire file
>  > system.
>  > 
>  > Allowing Access:
>  > 
>  > You can execute the following command as root to relabel your computer system:
>  > "touch /.autorelabel; reboot"
>  > 
>  > Additional Information:
>  > 
>  > Source Context unconfined_u:system_r:httpd_t:s0
>  > Target Context unconfined_u:object_r:file_t:s0
>  > Target Objects reststop [ dir ]
>  > Source httpd
>  > Source Path /usr/sbin/httpd
>  > Port <Unknown>
>  > Host secretsquirrel.com
>  > Source RPM Packages httpd-2.2.14-1.fc12
>  > Target RPM Packages
>  > Policy RPM selinux-policy-3.6.32-108.fc12
>  > Selinux Enabled True
>  > Policy Type targeted
>  > Enforcing Mode Permissive
>  > Plugin Name file
>  > Host Name secretsquirrel.com
>  > Platform Linux secretsquirrel.com
>  > 2.6.32.11-99.fc12.x86_64 #1 SMP Mon Apr 5 19:59:38
>  > UTC 2010 x86_64 x86_64
>  > Alert Count 1
>  > First Seen Mon 19 Apr 2010 03:45:40 PM BST
>  > Last Seen Mon 19 Apr 2010 03:45:40 PM BST
>  > Local ID yadayadayada
>  > Line Numbers
>  > 
>  > Raw Audit Messages
>  > 
>  > node=secretsquirrel.com type=AVC msg=audit(1288463622.694:23321): avc:
>  > denied { read } for pid=3605 comm="httpd" name="reststop"
> dev=dm-0
>  > ino=340012822 scontext=unconfined_u:system_r:httpd_t:s0
>  > tcontext=unconfined_u:object_r:file_t:s0 tclass=dir
>  > 
>  > node=secretsquirrel.com type=SYSCALL msg=audit(1288463622.694:23321):
>  > arch=c000003e syscall=2 success=yes exit=16 a0=7f2f691d91c0 a1=90800
>  > a2=7f2f691d5198 a3=7f2f691da150 items=0 ppid=3600 pid=3605 auid=500
>  > uid=48 gid=489 euid=48 suid=48 fsuid=48 egid=489 sgid=489 fsgid=489
>  > tty=(none) ses=2 comm="httpd" exe="/usr/sbin/httpd"
>  > subj=unconfined_u:system_r:httpd_t:s0 key=(null)
>  > 
>  > ----------------------------------------------------------------
>  > 
>  > Why is the error message telling me files are labelled file_t when
>  > they are labelled httpd_sys_content_t? To confirm that I ls -RZ | grep
>  > file_t in the two directories I get no files returned.
>  
>  Presumably o follow the symbolic link you need permission to
>  walk the link target's path.  Is any directory in the path
>  /mnt/anotherdrive/newpath/nearlythere/reststop
>  of type file_t?
>  
>  > What am I missing here guys? and before anyone suggests it I don't
>  > just want to turn selinux off, I want to actually protect my system
>  > properly though. 
Find the inode: find / -inum 340012822

You say you have mounted some partition in /mnt but the AVC denial says DM-0
I think that this may be related.

If you specified the contexts properly with semanage, then try restorecon -R -v /mnt

The avc denial takes about a dir with type file_t and name reststop on device DM-0 at
inode 340012822.

>  > 
>  > Thanks in advance
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