11.3. 問題の修正

導入部分

~]$ ls -l /var/www/html/index.html
-rw-r----- 1 root root 0 2009-05-07 11:06 index.html

~]# chown apache:apache /var/www/html/index.html
~]# semodule -DB
~]# semodule -B
~]$ sesearch --dontaudit -s smbd_t | grep squid
dontaudit smbd_t squid_port_t : tcp_socket name_bind ;
dontaudit smbd_t squid_port_t : udp_socket name_bind ;
~]# semanage permissive -a httpd_t
~]# semodule -l | grep permissive
permissive_httpd_t    (null)
permissivedomains     (null)

~]# semanage permissive -d httpd_t
~]# semodule -d permissivedomains
~]# semodule --list-modules=full
type=AVC msg=audit(1226882736.442:86): avc:  denied  { getattr } for  pid=2427 comm="httpd" path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226882736.442:86): arch=40000003 syscall=196 success=no exit=-13 a0=b9a1e198 a1=bfc2921c a2=54dff4 a3=2008171 items=0 ppid=2425 pid=2427 auid=502 uid=48 gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=4 comm="httpd" exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

type=AVC msg=audit(1226882925.714:136): avc:  denied  { read } for  pid=2512 comm="httpd" name="file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226882925.714:136): arch=40000003 syscall=5 success=yes exit=11 a0=b962a1e8 a1=8000 a2=0 a3=8000 items=0 ppid=2511 pid=2512 auid=502 uid=48 gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=4 comm="httpd" exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

~]# ausearch -m avc -c httpd
~]# ausearch -m avc -c smbd
~]# aureport -a

AVC Report
========================================================
# date time comm subj syscall class permission obj event
========================================================
1. 05/01/2009 21:41:39 httpd unconfined_u:system_r:httpd_t:s0 195 file getattr system_u:object_r:samba_share_t:s0 denied 2
2. 05/03/2009 22:00:25 vsftpd unconfined_u:system_r:ftpd_t:s0 5 file read unconfined_u:object_r:cifs_t:s0 denied 4

setroubleshoot: SELinux is preventing /usr/sbin/httpd from name_bind access on the tcp_socket. For complete SELinux messages. run sealert -l 8c123656-5dda-4e5d-8791-9e3bd03786b7

type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for  pid=2465 comm="httpd" path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13 a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48 gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd" exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

hostname setroubleshoot: SELinux is preventing httpd (httpd_t) "getattr" to /var/www/html/file1 (samba_share_t). For complete SELinux messages. run sealert -l 32eee32b-21ca-4846-a22f-0ba050206786

~]$ sealert -l 32eee32b-21ca-4846-a22f-0ba050206786
SELinux is preventing httpd from getattr access on the file /var/www/html/file1.

*****  Plugin restorecon (92.2 confidence) suggests   ************************

If you want to fix the label. 
/var/www/html/file1 default label should be httpd_sys_content_t.
Then you can run restorecon.
Do
# /sbin/restorecon -v /var/www/html/file1

*****  Plugin public_content (7.83 confidence) suggests   ********************

If you want to treat file1 as public content
Then you need to change the label on file1 to public_content_t or public_content_rw_t.
Do
# semanage fcontext -a -t public_content_t '/var/www/html/file1'
# restorecon -v '/var/www/html/file1'

*****  Plugin catchall (1.41 confidence) suggests   **************************

If you believe that httpd should be allowed getattr access on the file1 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 'httpd' --raw | audit2allow -M my-httpd
# semodule -i my-httpd.pp

Additional Information:
Source Context                system_u:system_r:httpd_t:s0
Target Context                unconfined_u:object_r:samba_share_t:s0
Target Objects                /var/www/html/file1 [ file ]
Source                        httpd
Source Path                   httpd
Port                          <Unknown>
Host                          hostname.redhat.com
Source RPM Packages           
Target RPM Packages           
Policy RPM                    selinux-policy-3.13.1-166.el7.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     hostname.redhat.com
Platform                      Linux hostname.redhat.com
                              3.10.0-693.el7.x86_64 #1 SMP Thu Jul 6 19:56:57
                              EDT 2017 x86_64 x86_64
Alert Count                   2
First Seen                    2017-07-20 02:52:11 EDT
Last Seen                     2017-07-20 02:52:11 EDT
Local ID                      32eee32b-21ca-4846-a22f-0ba050206786

Raw Audit Messages
type=AVC msg=audit(1500533531.140:295): avc:  denied  { getattr } for  pid=24934 comm="httpd" path="/var/www/html/file1" dev="vda1" ino=31457414 scontext=system_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

Hash: httpd,httpd_t,samba_share_t,file,getattr
type=AVC msg=audit(1226270358.848:238): avc:  denied  { write } for  pid=13349 comm="certwatch" name="cache" dev=dm-0 ino=218171 scontext=system_u:system_r:certwatch_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=dir

type=SYSCALL msg=audit(1226270358.848:238): arch=40000003 syscall=39 success=no exit=-13 a0=39a2bf a1=3ff a2=3a0354 a3=94703c8 items=0 ppid=13344 pid=13349 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="certwatch" exe="/usr/bin/certwatch" subj=system_u:system_r:certwatch_t:s0 key=(null)

~]# audit2allow -w -a
type=AVC msg=audit(1226270358.848:238): avc:  denied  { write } for  pid=13349 comm="certwatch" name="cache" dev=dm-0 ino=218171 scontext=system_u:system_r:certwatch_t:s0 tcontext=system_u:object_r:var_t:s0 tclass=dir
	Was caused by:
		Missing type enforcement (TE) allow rule.

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

~]# audit2allow -a

#============= certwatch_t ==============
allow certwatch_t var_t:dir write;

~]# audit2allow -a -M mycertwatch
******************** IMPORTANT ***********************
To make this policy package active, execute:

semodule -i mycertwatch.pp

~]# ls
mycertwatch.pp  mycertwatch.te

~]# semodule -i mycertwatch.pp
~]# grep certwatch /var/log/audit/audit.log | audit2allow -R -M mycertwatch2
******************** IMPORTANT ***********************
To make this policy package active, execute:

semodule -i mycertwatch2.pp

11.3. 問題の修正

11.3.1. Linux の権限

11.3.2. サイレント拒否の考えられる原因

11.3.3. サービスの man ページ

11.3.4. Permissive ドメイン

11.3.4.1. ドメインを Permissive にする

11.3.4.2. Permissive ドメインの無効化

11.3.4.3. Permissive ドメインの拒否

11.3.5. 拒否の検索と表示

ausearch

aureport

sealert

11.3.6. Raw 監査メッセージ

11.3.7. sealert メッセージ

11.3.8. アクセスの許可: audit2allow

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