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Starting with selinux-policy-3.13.1-252.el7.1 we're seeing hundreds of messages with the following three variants:
SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /tmp/5d8d011ec6286
SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file 5d8d011ed8a30
SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /etc/cups/ppd/myprinter.ppd
All of them indicate the same alert ID on a given system. Here is an example:
$ sealert -l 6ade7ae9-9d26-44fc-b600-bc614d5be1e0
SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /tmp/5d8e40cc6824c.
***** Plugin restorecon (99.5 confidence) suggests ************************
If you want to fix the label.
/tmp/5d8e40cc6824c default label should be default_t.
Then you can run restorecon. The access attempt may have been stopped due to insufficient permissions to access a parent directory in which case try to change the following command accordingly.
Do
# /sbin/restorecon -v /tmp/5d8e40cc6824c
***** Plugin catchall (1.49 confidence) suggests **************************
If you believe that cups-browsed should be allowed create access on the 5d8e40cc6824c lnk_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 'cups-browsed' --raw | audit2allow -M my-cupsbrowsed
# semodule -i my-cupsbrowsed.pp
Additional Information:
Source Context system_u:system_r:cupsd_t:s0-s0:c0.c1023
Target Context system_u:object_r:tmp_t:s0
Target Objects /tmp/5d8e40cc6824c [ lnk_file ]
Source cups-browsed
Source Path /usr/sbin/cups-browsed
Port <Unknown>
Host [REDACTED]
Source RPM Packages cups-filters-1.0.35-26.el7.x86_64
Target RPM Packages
Policy RPM selinux-policy-3.13.1-252.el7.1.noarch
Selinux Enabled True
Policy Type targeted
Enforcing Mode Enforcing
Host Name [REDACTED]
Platform Linux [REDACTED] 3.10.0-1062.1.1.el7.x86_64 #1
SMP Fri Sep 13 22:55:44 UTC 2019 x86_64 x86_64
Alert Count 631
First Seen 2019-09-20 15:37:23 EDT
Last Seen 2019-09-27 13:03:08 EDT
Local ID 6ade7ae9-9d26-44fc-b600-bc614d5be1e0
Raw Audit Messages
type=AVC msg=audit(1569603788.425:206862): avc: denied { create } for pid=2114 comm="cups-browsed" name="5d8e40cc6824c" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tmp_t:s0 tclass=lnk_file permissive=0
type=SYSCALL msg=audit(1569603788.425:206862): arch=x86_64 syscall=symlink success=no exit=EACCES a0=7fff093f1d00 a1=55744cc57718 a2=55744cc5772a a3=5d8e40cc items=3 ppid=1 pid=2114 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm=cups-browsed exe=/usr/sbin/cups-browsed subj=system_u:system_r:cupsd_t:s0-s0:c0.c1023 key=(null)
type=CWD msg=audit(1569603788.425:206862): cwd=/
type=PATH msg=audit(1569603788.425:206862): item=0 name=/etc/cups/ppd/myprinter.ppd objtype=UNKNOWN cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
type=PATH msg=audit(1569603788.425:206862): item=1 name=/tmp/ inode=132 dev=fd:02 mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmp_t:s0 objtype=PARENT cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
type=PATH msg=audit(1569603788.425:206862): item=2 name=/tmp/5d8e40cc6824c objtype=CREATE cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0
Hash: cups-browsed,cupsd_t,tmp_t,lnk_file,create
The filenames consisting of hex strings do not appear to exist (I guess because the create failed?), so we can't verify if they're symlinks or not or what their context is. The PPD files do exist; for example:
$ ls -lZ /etc/cups/ppd/myprinter.ppd
-rw-r--r--. root root system_u:object_r:cupsd_rw_etc_t:s0 /etc/cups/ppd/myprinter.ppd
It is not however a symlink, which I assume is what "lnk_file" is supposed to indicate.
Running "ausearch -c 'cups-browsed' --raw | audit2allow -M my-cupsbrowsed" produces a .te file containing the following warning:
#!!!! WARNING 'cupsd_t' is not allowed to write or create to tmp_t. Change the label to cupsd_tmp_t.
allow cupsd_t tmp_t:lnk_file create;
Note that Bz 1401634 appears to be the same selinux-policy issue in Fedora 26, which was apparently fixed in selinux-policy-3.13.1-251.fc26. Unclear if that patch was included in selinux-policy-3.13.1-252.el7.1 or not.
Starting with selinux-policy-3.13.1-252.el7.1 we're seeing hundreds of messages with the following three variants: SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /tmp/5d8d011ec6286 SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file 5d8d011ed8a30 SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /etc/cups/ppd/myprinter.ppd All of them indicate the same alert ID on a given system. Here is an example: $ sealert -l 6ade7ae9-9d26-44fc-b600-bc614d5be1e0 SELinux is preventing /usr/sbin/cups-browsed from create access on the lnk_file /tmp/5d8e40cc6824c. ***** Plugin restorecon (99.5 confidence) suggests ************************ If you want to fix the label. /tmp/5d8e40cc6824c default label should be default_t. Then you can run restorecon. The access attempt may have been stopped due to insufficient permissions to access a parent directory in which case try to change the following command accordingly. Do # /sbin/restorecon -v /tmp/5d8e40cc6824c ***** Plugin catchall (1.49 confidence) suggests ************************** If you believe that cups-browsed should be allowed create access on the 5d8e40cc6824c lnk_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 'cups-browsed' --raw | audit2allow -M my-cupsbrowsed # semodule -i my-cupsbrowsed.pp Additional Information: Source Context system_u:system_r:cupsd_t:s0-s0:c0.c1023 Target Context system_u:object_r:tmp_t:s0 Target Objects /tmp/5d8e40cc6824c [ lnk_file ] Source cups-browsed Source Path /usr/sbin/cups-browsed Port <Unknown> Host [REDACTED] Source RPM Packages cups-filters-1.0.35-26.el7.x86_64 Target RPM Packages Policy RPM selinux-policy-3.13.1-252.el7.1.noarch Selinux Enabled True Policy Type targeted Enforcing Mode Enforcing Host Name [REDACTED] Platform Linux [REDACTED] 3.10.0-1062.1.1.el7.x86_64 #1 SMP Fri Sep 13 22:55:44 UTC 2019 x86_64 x86_64 Alert Count 631 First Seen 2019-09-20 15:37:23 EDT Last Seen 2019-09-27 13:03:08 EDT Local ID 6ade7ae9-9d26-44fc-b600-bc614d5be1e0 Raw Audit Messages type=AVC msg=audit(1569603788.425:206862): avc: denied { create } for pid=2114 comm="cups-browsed" name="5d8e40cc6824c" scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tmp_t:s0 tclass=lnk_file permissive=0 type=SYSCALL msg=audit(1569603788.425:206862): arch=x86_64 syscall=symlink success=no exit=EACCES a0=7fff093f1d00 a1=55744cc57718 a2=55744cc5772a a3=5d8e40cc items=3 ppid=1 pid=2114 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm=cups-browsed exe=/usr/sbin/cups-browsed subj=system_u:system_r:cupsd_t:s0-s0:c0.c1023 key=(null) type=CWD msg=audit(1569603788.425:206862): cwd=/ type=PATH msg=audit(1569603788.425:206862): item=0 name=/etc/cups/ppd/myprinter.ppd objtype=UNKNOWN cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0 type=PATH msg=audit(1569603788.425:206862): item=1 name=/tmp/ inode=132 dev=fd:02 mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmp_t:s0 objtype=PARENT cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0 type=PATH msg=audit(1569603788.425:206862): item=2 name=/tmp/5d8e40cc6824c objtype=CREATE cap_fp=0000000000000000 cap_fi=0000000000000000 cap_fe=0 cap_fver=0 Hash: cups-browsed,cupsd_t,tmp_t,lnk_file,create The filenames consisting of hex strings do not appear to exist (I guess because the create failed?), so we can't verify if they're symlinks or not or what their context is. The PPD files do exist; for example: $ ls -lZ /etc/cups/ppd/myprinter.ppd -rw-r--r--. root root system_u:object_r:cupsd_rw_etc_t:s0 /etc/cups/ppd/myprinter.ppd It is not however a symlink, which I assume is what "lnk_file" is supposed to indicate. Running "ausearch -c 'cups-browsed' --raw | audit2allow -M my-cupsbrowsed" produces a .te file containing the following warning: #!!!! WARNING 'cupsd_t' is not allowed to write or create to tmp_t. Change the label to cupsd_tmp_t. allow cupsd_t tmp_t:lnk_file create; Note that Bz 1401634 appears to be the same selinux-policy issue in Fedora 26, which was apparently fixed in selinux-policy-3.13.1-251.fc26. Unclear if that patch was included in selinux-policy-3.13.1-252.el7.1 or not.