On Fri, Oct 20, 2017 at 01:59:00PM +0200, Winberg, Adam wrote:
I'm running tests with using sssd for smartcard auth as an
pam_pkcs11
replacement. I've gotten it to work, but am getting a _lot_ of selinux
denials.
It seems that p11_child inherits the sssd selinux context and therefore
runs in the 'sssd_t' domain. This causes problems since p11_child seems to
want access to a whole lot of stuff. Some examples:
SELinux is preventing /usr/libexec/sssd/p11_child from search access on the
directory fs.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /dev/hugepages.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /proc/fs/nfsd.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /boot.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /home.
SELinux is preventing /usr/libexec/sssd/p11_child from search access on the
directory /var/lib/nfs.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /.
SELinux is preventing /usr/libexec/sssd/p11_child from execute access on
the file /run/user/60483/ffiSOUzGu (deleted).
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /sys/fs/fuse/connections.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /dev.
SELinux is preventing /usr/libexec/sssd/p11_child from execute access on
the file /dev/shm/ffi8thWCx (deleted).
SELinux is preventing /usr/libexec/sssd/p11_child from execute access on
the file /run/ffi24njzA (deleted).
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /sys/kernel/config.
SELinux is preventing /usr/libexec/sssd/p11_child from write access on the
directory /sys/fs/selinux.
The p11_child code itself does not try to open anything it completely
depends on NSS to access the Smartcard. From you previous question it
looks like you have added the p11-kit modules to /etc/pki/nssdb. I would
expect that this is trying to access the file system.
HTH
bye,
Sumit
An Sealert output:
SELinux is preventing /usr/libexec/sssd/p11_child from search access on the
directory .config.
***** Plugin catchall (100. confidence) suggests
**************************
If you believe that p11_child should be allowed search access on the
.config 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 'p11_child' --raw | audit2allow -M my-p11child
# semodule -i my-p11child.pp
Additional Information:
Source Context system_u:system_r:sssd_t:s0
Target Context unconfined_u:object_r:config_home_t:s0
Target Objects .config [ dir ]
Source p11_child
Source Path /usr/libexec/sssd/p11_child
Port <Unknown>
Host c21226.ad.smhi.se
Source RPM Packages sssd-krb5-common-1.15.2-50.el7_4.6.x86_64
Target RPM Packages
Policy RPM selinux-policy-3.13.1-166.el7_4.5.noarch
Selinux Enabled True
Policy Type targeted
Enforcing Mode Enforcing
Host Name c21226.ad.smhi.se
Platform Linux c21226.ad.smhi.se
3.10.0-693.5.2.el7.x86_64
#1 SMP Fri Oct 13 10:46:25 EDT 2017 x86_64
x86_64
Alert Count 29
First Seen 2017-10-20 08:14:10 CEST
Last Seen 2017-10-20 13:21:38 CEST
Local ID 17d70bbe-a54d-47c3-8515-985d6646a93f
Raw Audit Messages
type=AVC msg=audit(1508498498.877:13286): avc: denied { search } for
pid=29036 comm="krb5_child" name=".config" dev="sda2"
ino=16782181
scontext=system_u:system_r:sssd_t:s0
tcontext=unconfined_u:object_r:config_home_t:s0 tclass=dir
type=SYSCALL msg=audit(1508498498.877:13286): arch=x86_64 syscall=openat
success=no exit=EACCES a0=ffffffffffffff9c a1=56536c43c350 a2=90800 a3=0
items=0 ppid=20098 pid=29036 auid=4294967295 uid=0 gid=0 euid=0 suid=0
fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm=krb5_child
exe=/usr/libexec/sssd/krb5_child subj=system_u:system_r:sssd_t:s0 key=(null)
Hash: p11_child,sssd_t,config_home_t,dir,search
Whats with all the acceses, is that normal? And if so, how's that suppose
to work while running in the 'sssd_t' context?
Regards
Adam
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