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Bug 2174445 - SELinux is preventing /usr/bin/smbspool from write/add_name/create on /var/lib/samba/lock/ and /var/lib/samba/lock/gencache.tdb
Summary: SELinux is preventing /usr/bin/smbspool from write/add_name/create on /var/li...
Keywords:
Status: CLOSED ERRATA
Alias: None
Deadline: 2023-05-16
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: selinux-policy
Version: 9.1
Hardware: Unspecified
OS: Linux
medium
medium
Target Milestone: rc
: ---
Assignee: Nobody
QA Contact: Milos Malik
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2023-03-01 16:17 UTC by Matthias Olson
Modified: 2023-11-07 11:21 UTC (History)
3 users (show)

Fixed In Version: selinux-policy-38.1.13-1.el9
Doc Type: No Doc Update
Doc Text:
Clone Of:
Environment:
Last Closed: 2023-11-07 08:52:19 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHELPLAN-150320 0 None None None 2023-03-01 16:19:42 UTC
Red Hat Product Errata RHBA-2023:6617 0 None None None 2023-11-07 08:52:37 UTC

Description Matthias Olson 2023-03-01 16:17:40 UTC 
Description of problem:

After installing samba-krb5-printing and setting up an SMB Printer with Kerberos authentication, attempts at printing fail due to the SELinux policy-set.

Suggested allow rule may be too broad (i.e. giving cupsd_t context required permissions over the entirety of samba_var_t).

--------------------------------------------------

From journald:

setroubleshoot[5782]: SELinux is preventing /usr/bin/smbspool from write access on the directory /var/lib/samba/lock/.
                                                                   
                                                                   *****  Plugin catchall (100. confidence) suggests   **************************
                                                                   
                                                                   If you believe that smbspool should be allowed write access on the  directory by default.
                                                                   Then you should report this as a bug.
                                                                   You can generate a local policy module to allow this access.
                                                                   Do
                                                                   allow this access for now by executing:
                                                                   # ausearch -c 'smbspool' --raw | audit2allow -M my-smbspool
                                                                   # semodule -X 300 -i my-smbspool.pp

setroubleshoot[6984]: SELinux is preventing /usr/bin/smbspool from add_name access on the directory /var/lib/samba/lock/.
                                                                   
                                                                   *****  Plugin catchall (100. confidence) suggests   **************************
                                                                   
                                                                   If you believe that smbspool should be allowed add_name access on the  directory by default.
                                                                   Then you should report this as a bug.
                                                                   You can generate a local policy module to allow this access.
                                                                   Do
                                                                   allow this access for now by executing:
                                                                   # ausearch -c 'smbspool' --raw | audit2allow -M my-smbspool
                                                                   # semodule -X 300 -i my-smbspool.pp

setroubleshoot[7460]: SELinux is preventing /usr/bin/smbspool from create access on the file /var/lib/samba/lock/.
                                                                   
                                                                   *****  Plugin catchall (100. confidence) suggests   **************************
                                                                   
                                                                   If you believe that smbspool should be allowed create access on the  file by default.
                                                                   Then you should report this as a bug.
                                                                   You can generate a local policy module to allow this access.
                                                                   Do
                                                                   allow this access for now by executing:
                                                                   # ausearch -c 'smbspool' --raw | audit2allow -M my-smbspool
                                                                   # semodule -X 300 -i my-smbspool.pp

--------------------------------------------------

The output of `ausearch -c 'smbspool' --raw | audit2allow -w -a`:

type=AVC msg=audit(1677683022.381:1713): avc:  denied  { write } for  pid=5779 comm="smbspool" name="lock" dev="dm-1" ino=201463076 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683022.381:1714): avc:  denied  { write } for  pid=5779 comm="smbspool" name="lock" dev="dm-1" ino=201463076 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683022.384:1715): avc:  denied  { write } for  pid=5779 comm="smbspool" name="lock" dev="dm-1" ino=201463076 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683165.831:2825): avc:  denied  { add_name } for  pid=6982 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683165.831:2826): avc:  denied  { add_name } for  pid=6982 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683165.833:2827): avc:  denied  { add_name } for  pid=6982 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683400.064:2971): avc:  denied  { create } for  pid=7458 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=file permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683400.064:2972): avc:  denied  { create } for  pid=7458 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=file permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

type=AVC msg=audit(1677683400.066:2973): avc:  denied  { create } for  pid=7458 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=file permissive=0
        Was caused by:
                Missing type enforcement (TE) allow rule.

                You can use audit2allow to generate a loadable module to allow this access.

--------------------------------------------------

The output of `ausearch -c 'smbspool' --raw | audit2allow -a`

#============= cupsd_t ==============
allow cupsd_t samba_var_t:dir { add_name write };
allow cupsd_t samba_var_t:file create;

--------------------------------------------------

Version-Release number of selected component (if applicable):
selinux-policy.noarch 34.1.43-1.el9_1.1
samba-krb5-printing.x86_64 4.16.4-101.el9 

How reproducible:
100%
Comment 1 Nikola Knazekova 2023-03-24 20:09:08 UTC 
Hi Matthias,

can you please reproduce the issue in permissive mode and attach SELinux denials?

Please do:
# setenforce 0

Thank you,
Nikola
Comment 3 Matthias Olson 2023-04-18 08:56:30 UTC 
In permissive mode the output is:
setroubleshoot[13501]: SELinux is preventing /usr/bin/smbspool from write access on the directory /var/lib/samba/lock/gencache.tdb.
                                                                    
                                                                    *****  Plugin catchall (100. confidence) suggests   **************************
                                                                    
                                                                    If you believe that smbspool should be allowed write access on the gencache.tdb directory by default.
                                                                    Then you should report this as a bug.
                                                                    You can generate a local policy module to allow this access.
                                                                    Do
                                                                    allow this access for now by executing:
                                                                    # ausearch -c 'smbspool' --raw | audit2allow -M my-smbspool
                                                                    # semodule -X 300 -i my-smbspool.pp

Audit log:

type=AVC msg=audit(1681807537.277:6645): avc:  denied  { write } for  pid=13496 comm="smbspool" name="lock" dev="dm-1" ino=201463076 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=1
type=AVC msg=audit(1681807537.277:6645): avc:  denied  { add_name } for  pid=13496 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=dir permissive=1
type=AVC msg=audit(1681807537.277:6645): avc:  denied  { create } for  pid=13496 comm="smbspool" name="gencache.tdb" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:samba_var_t:s0 tclass=file permissive=1
type=SYSCALL msg=audit(1681807537.277:6645): arch=c000003e syscall=257 success=yes exit=6 a0=ffffff9c a1=55f0e1e3b5f0 a2=80042 a3=1a4 items=2 ppid=2328 pid=13496 auid=4294967295 uid=0 gid=7 euid=0 suid=0 fsuid=0 egid=7 sgid=7 fsgid=7 tty=(none) ses=4294967295 comm="smbspool" exe="/usr/bin/smbspool" subj=system_u:system_r:cupsd_t:s0-s0:c0.c1023 key=(null)ARCH=x86_64 SYSCALL=openat AUID="unset" UID="root" GID="lp" EUID="root" SUID="root" FSUID="root" EGID="lp" SGID="lp" FSGID="lp"
type=PATH msg=audit(1681807537.277:6645): item=0 name="/var/lib/samba/lock/" inode=201463076 dev=fd:01 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:samba_var_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0OUID="root" OGID="root"
type=PATH msg=audit(1681807537.277:6645): item=1 name="/var/lib/samba/lock/gencache.tdb" inode=201477594 dev=fd:01 mode=0100600 ouid=0 ogid=7 rdev=00:00 obj=system_u:object_r:samba_var_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0OUID="root" OGID="lp"
type=PROCTITLE msg=audit(1681807537.277:6645): proctitle=736D623A2F2F69732D7072696E742E68712E74726179706F72742E636F6D2F42575F4455504C45585F325000313600726F6F74005465737420506167650031006A6F622D757569643D75726E3A757569643A30386139366239392D626637372D333864612D356631382D356465316266343963316439206A6F622D6F72696769
Comment 13 errata-xmlrpc 2023-11-07 08:52:19 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (selinux-policy bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:6617
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