Am 26.07.20 um 12:23 schrieb Strahil Nikolov:
На 25 юли 2020 г. 14:20:19 GMT+03:00, Leon Fauster via CentOS centos@centos.org написа:
Hi all,
I have some AVC in the logs and wonder how to resolve this: Under EL8 (enforcing SElinux) I have /var/lib/php/session mounted as tmpfs.
# tail -1 /etc/fstab tmpfs /var/lib/php/session tmpfs defaults,noatime,mode=770,gid=apache,size=16777216,context="system_u:object_r:httpd_var_run_t:s0"
0 0
# df -a |grep php tmpfs 16384 0 16384 0% /var/lib/php/session
# ls -laZ /var/lib/php/session insgesamt 0 drwxrwx---. 2 root apache system_u:object_r:httpd_var_run_t:s0 40 24. Jul 15:36 . drwxr-xr-x. 6 root root system_u:object_r:httpd_var_lib_t:s0 68 7. Jul 10:54 ..
the applications can read the session data without any problems.
When I reboot the system following AVC appears:
# last |grep ^re|head -3 reboot system boot 4.18.0-193.6.3.e Fri Jul 24 15:28 still running reboot system boot 4.18.0-193.6.3.e Fri Jul 24 13:33 - 15:27 (01:54) reboot system boot 4.18.0-193.6.3.e Fri Jul 24 01:20 - 13:33 (12:13)
# ausearch -m avc --start today
time->Fri Jul 24 01:20:08 2020 type=AVC msg=audit(1595546408.754:28): avc: denied { remount } for pid=952 comm="(ostnamed)" scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:httpd_var_run_t:s0 tclass=filesystem permissive=0
time->Fri Jul 24 13:34:04 2020 type=AVC msg=audit(1595590444.080:29): avc: denied { remount } for pid=1020 comm="(ostnamed)" scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:httpd_var_run_t:s0 tclass=filesystem permissive=0
time->Fri Jul 24 15:28:40 2020 type=AVC msg=audit(1595597320.783:28): avc: denied { remount } for pid=934 comm="(ostnamed)" scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:httpd_var_run_t:s0 tclass=filesystem permissive=0
I wonder about the "remount" and the comm="ostnamed".
I do not found any ostnamed application, the closest is hostnamed.
Should the tmpfs be mounted differently (without fstab entry)?
To get rid of the AVC I could add the corresponding policy "allow init_t httpd_var_run_t:filesystem remount;" but is this not a bit of overkill?
Any hints about what the cause is?
I'd really appreciate any ideas on this.
Hi Leon,
have you tried mounting with 'httpd_sys_rw_content_t' instead of
'httpd_var_run_t' ?
The latter is the standard selinux context. So I prefer to go with it.
umount /var/lib/php/session restorecon -v -R /var/lib/php/
# LANG=C ls -laZ /var/lib/php/session total 8 drwxrwx---. 2 root apache system_u:object_r:httpd_var_run_t:s0 4096 May 7 04:39 .
mount /var/lib/php/session/ # LANG=C ls -laZ /var/lib/php/session total 4 drwxrwx---. 2 root apache system_u:object_r:httpd_var_run_t:s0 40 Jul 26 17:19 .
The application does NOT have any problems to write to this directory.
Its "just" the audit/AVC denys that are the issues ...
I'm not sure what triggers this remounts?
-- Leon