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Description of problem: If selinux is enforcing and NFSv4 client uses KRB5 security and ssh is configured with GSSAPI, rpc.gssd cannot create security context: rpc.gssd[75903]: ERROR: GSS-API: error in gss_acquire_cred(): GSS_S_FAILURE (Unspecified GSS failure. Minor code may provide more information) - (0x9ae73ac4) rpc.gssd[75903]: WARNING: Failed while limiting krb5 encryption types for user with uid 0 rpc.gssd[75903]: WARNING: Failed to create machine krb5context with cred cache FILE:/tmp/krb5ccmachine_ICS.MUNI.CZ for server storage-brno3-cerit.metacentrum.cz I believe, this is due to: type=AVC msg=audit(1563060569.732:5664): avc: denied { unlink } for pid=46136 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=1 this is the file: ls -Z /tmp/krb5cc_0 -rw-------. root root system_u:object_r:gssd_tmp_t:s0 /tmp/krb5cc_0 if I set selinux to permissive, everything works. Version-Release number of selected component (if applicable): everything from 7.6 RHEL up to date.
(In reply to Lukas Hejtmanek from comment #0) Hey Lukas, I didn't see this AVC during my krb5/NFS testings. > this is the file: > ls -Z /tmp/krb5cc_0 > -rw-------. root root system_u:object_r:gssd_tmp_t:s0 /tmp/krb5cc_0 It's different from my side: [root]# ls -Z /tmp/krb5cc_0 -rw-------. root root unconfined_u:object_r:user_tmp_t:s0 /tmp/krb5cc_0 [root]# getenforce Enforcing > > Version-Release number of selected component (if applicable): > everything from 7.6 RHEL up to date. By the way, have you tried any version before 7.6? Does it work as expected?
Did you try to mount any kerberize NFS volume while there is that -rw-------. root root unconfined_u:object_r:user_tmp_t:s0 /tmp/krb5cc_0 file? I did not test any previous version.
Okay, after mounting as krb5, the "security context" is updated to "system_u:object_r:gssd_tmp_t:s0". But I still didn't encounter the failure of comment #0: ----------------------------------------------------- [root ~]# mount -t nfs4 -o sec=krb5 $HOSTNAME:/ /mnt/ [root ~]# nfsstat -m /mnt from rhel-7.7.redhat.com:/ Flags: rw,relatime,vers=4.1,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5,clientaddr=10.10.10.10,local_lock=none,addr=10.10.10.10 [root ~]# ls -Z /tmp/krb5cc_0 -rw-------. root root system_u:object_r:gssd_tmp_t:s0 /tmp/krb5cc_0 ^^^^^^^^^ [root ~]# grep gssd /var/log/messages | egrep -i "err|warn" [root ~]# grep denied /var/log/audit/audit.log [root ~]#
[root@ursa ~]# sestatus SELinux status: enabled SELinuxfs mount: /sys/fs/selinux SELinux root directory: /etc/selinux Loaded policy name: targeted Current mode: enforcing Mode from config file: enforcing Policy MLS status: enabled Policy deny_unknown status: allowed Max kernel policy version: 31 [root@ursa ~]# [root@ursa ~]# mount -t nfs4 -o sec=krb5 storage-brno1-cerit.metacentrum.cz:/ /mnt/storage-brno1-cerit mount.nfs4: access denied by server while mounting storage-brno1-cerit.metacentrum.cz:/ [root@ursa ~]# ls -Z /tmp/krb5cc_0 -rw-------. root root system_u:object_r:tmp_t:s0 /tmp/krb5cc_0 [root@ursa ~]# [root@ursa ~]# date Tue Jul 23 01:35:50 CEST 2019 [root@ursa ~]# grep gssd /var/log/messages | egrep -i "err|warn" [root@ursa ~]# grep denied /var/log/audit/audit.log type=AVC msg=audit(1563838547.187:235): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.189:236): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.191:237): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.193:238): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.196:239): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.198:240): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.252:241): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.254:242): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.256:243): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.257:244): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.270:245): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 type=AVC msg=audit(1563838547.272:246): avc: denied { unlink } for pid=45595 comm="rpc.gssd" name="krb5cc_0" dev="md126p4" ino=67160166 scontext=system_u:system_r:gssd_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file permissive=0 [root@ursa ~]# rm /tmp/krb5cc_0 rm: remove regular file ‘/tmp/krb5cc_0’? y [root@ursa ~]# mount -t nfs4 -o sec=krb5 storage-brno1-cerit.metacentrum.cz:/ /mnt/storage-brno1-cerit [root@ursa ~]# [root@ursa ~]# ls -Z /tmp/krb5cc_0 -rw-------. root root system_u:object_r:gssd_tmp_t:s0 /tmp/krb5cc_0 [root@ursa ~]#