SSHD and SELinux entrypoint access denied
Description of problem:
Upon system bootup, everything is fine and no issue occur. However as root, restart the sshd and then the users ssh connection is presented with :
@####'s password:
Last login: Fri Feb 7 14:36:55 UTC 2014 from ### on pts/1
Last login: Fri Feb 7 14:38:37 2014 from ###
/bin/bash: Permission denied
Connection to #### closed.
Selinux shows this in the logs:
type=AVC msg=audit(1391783451.309:99): avc: denied { entrypoint } for pid=3461 comm="sshd" path="/bin/bash" dev=dm-0 ino=4774818 scontext=user_u:system_r:update_modules_t:s0 tcontext=system_u:object_r:shell_exec_t:s0 tclass=file
type=AVC msg=audit(1391783815.832:111): avc: denied { entrypoint } for pid=3489 comm="sshd" path="/bin/bash" dev=dm-0 ino=4774818 scontext=user_u:system_r:update_modules_t:s0 tcontext=system_u:object_r:shell_exec_t:s0 tclass=file
type=AVC msg=audit(1391783917.334:125): avc: denied { entrypoint } for pid=3527 comm="sshd" path="/bin/bash" dev=dm-0 ino=4774818 scontext=user_u:system_r:update_modules_t:s0 tcontext=system_u:object_r:shell_exec_t:s0 tclass=file
setroubleshoot: SELinux is preventing sshd (update_modules_t) "entrypoint" to /bin/bash (shell_exec_t). For complete SELinux messages. run sealert -l b134f048-ea68-41c1-a35e-6c1dd6f18c44
sealert -l b134f048-ea68-41c1-a35e-6c1dd6f18c44
Summary:
SELinux is preventing sshd (update_modules_t) "entrypoint" to /bin/bash
(shell_exec_t).
Detailed Description:
SELinux denied access requested by sshd. It is not expected that this access is
required by sshd and this access may signal an intrusion attempt. It is also
possible that the specific version or configuration of the application is
causing it to require additional access.
Allowing Access:
Sometimes labeling problems can cause SELinux denials. You could try to restore
the default system file context for /bin/bash,
restorecon -v '/bin/bash'
If this does not work, there is currently no automatic way to allow this access.
Instead, you can generate a local policy module to allow this access - see FAQ
(http://fedora.redhat.com/docs/selinux-faq-fc5/#id2961385) Or you can disable
SELinux protection altogether. Disabling SELinux protection is not recommended.
Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi)
against this package.
Additional Information:
Source Context user_u:system_r:update_modules_t
Target Context system_u:object_r:shell_exec_t
Target Objects /bin/bash [ file ]
Source sshd
Source Path /usr/sbin/sshd
Port
Host hal04.halogenonline.co.uk
Source RPM Packages openssh-server-4.3p2-82.el5
Target RPM Packages bash-3.2-32.el5_9.1
Policy RPM selinux-policy-2.4.6-346.el5
Selinux Enabled True
Policy Type targeted
MLS Enabled True
Enforcing Mode Enforcing
Plugin Name catchall_file
Host Name hal04.halogenonline.co.uk
Platform Linux hal04.halogenonline.co.uk 2.6.18-371.3.1.el5
#1 SMP Mon Nov 11 03:24:35 EST 2013 i686 i686
Alert Count 29
First Seen Wed Feb 5 15:53:59 2014
Last Seen Fri Feb 7 12:20:43 2014
Local ID b134f048-ea68-41c1-a35e-6c1dd6f18c44
Line Numbers
Raw Audit Messages
host=hal04.halogenonline.co.uk type=AVC msg=audit(1391775643.42:73): avc: denied { entrypoint } for pid=3333 comm="sshd" path="/bin/bash" dev=dm-0 ino=4774818 scontext=user_u:system_r:update_modules_t:s0 tcontext=system_u:object_r:shell_exec_t:s0 tclass=file
host=hal04.halogenonline.co.uk type=SYSCALL msg=audit(1391775643.42:73): arch=40000003 syscall=11 success=no exit=-13 a0=8476868 a1=bf7ff828 a2=847cef8 a3=0 items=0 ppid=3332 pid=3333 auid=503 uid=503 gid=503 euid=503 suid=503 fsuid=503 egid=503 sgid=503 fsgid=503 tty=pts1 ses=5 comm="sshd" exe="/usr/sbin/sshd" subj=user_u:sysadm_r:unconfined_t:s0-s0:c0.c1023 key=(null)
Version-Release number of selected component (if applicable):
openssh-server-4.3p2-82.el5
libselinux-devel-1.33.4-5.7.el5
selinux-policy-targeted-2.4.6-346.el5
libselinux-1.33.4-5.7.el5
selinux-policy-2.4.6-346.el5
selinux-policy-minimum-2.4.6-346.el5
libselinux-utils-1.33.4-5.7.el5
libselinux-python-1.33.4-5.7.el5
Feb 7 14:30:51 hal04 setroubleshoot: SELinux is preventing sshd (update_modules_t) "entrypoint" to /bin/bash (shell_exec_t). For complete SELinux messages. run sealert -l c65c8e44-d025-477f-aec1-64429b734f62
Feb 7 14:36:55 hal04 setroubleshoot: SELinux is preventing sshd (update_modules_t) "entrypoint" to /bin/bash (shell_exec_t). For complete SELinux messages. run sealert -l c65c8e44-d025-477f-aec1-64429b734f62
Feb 7 14:38:37 hal04 setroubleshoot: SELinux is preventing sshd (update_modules_t) "entrypoint" to /bin/bash (shell_exec_t). For complete SELinux messages. run sealert -l c65c8e44-d025-477f-aec1-64429b734f62
How reproducible:
Steps to Reproduce:
1. Run RHEL 5 system
2. restart sshd
3. try to ssh to system
Actual results:
selinux blocks entrypoint
Expected results:
selinux should allow entrypoint
Additional info:
Two systems build using simuarl kickstarts occour with this issue.
System reboot will restore sshd connectivity as well as setenforce 0.
System with selinux enforcing on bootup will allow ssh connection.
https://bugzilla.redhat.com/show_bug.cgi?id=1062643
Responses