selinux-refpolicy/policy/modules/services/ssh.if
Nicolas Iooss 3734d7e76c ssh: use dac_read_search instead of dac_override
When creating a session for a new user, sshd performs a stat() call
somewhere:

    type=AVC msg=audit(1502951786.649:211): avc:  denied  {
    dac_read_search } for  pid=274 comm="sshd" capability=2
    scontext=system_u:system_r:sshd_t tcontext=system_u:system_r:sshd_t
    tclass=capability permissive=1

    type=SYSCALL msg=audit(1502951786.649:211): arch=c000003e syscall=4
    success=no exit=-2 a0=480e79b300 a1=7ffe0e09b080 a2=7ffe0e09b080
    a3=7fb2aa321b20 items=0 ppid=269 pid=274 auid=1000 uid=0 gid=0
    euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=1
    comm="sshd" exe="/usr/bin/sshd" subj=system_u:system_r:sshd_t
    key=(null)

    type=PROCTITLE msg=audit(1502951786.649:211):
    proctitle=737368643A2076616772616E74205B707269765D
2019-01-05 21:21:18 +01:00

777 lines
18 KiB
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## <summary>Secure shell client and server policy.</summary>
#######################################
## <summary>
## Basic SSH client template.
## </summary>
## <desc>
## <p>
## This template creates a derived domains which are used
## for ssh client sessions. A derived
## type is also created to protect the user ssh keys.
## </p>
## <p>
## This template was added for NX.
## </p>
## </desc>
## <param name="userdomain_prefix">
## <summary>
## The prefix of the domain (e.g., user
## is the prefix for user_t).
## </summary>
## </param>
## <param name="user_domain">
## <summary>
## The type of the domain.
## </summary>
## </param>
## <param name="user_role">
## <summary>
## The role associated with the user domain.
## </summary>
## </param>
#
template(`ssh_basic_client_template',`
gen_require(`
attribute ssh_server;
type ssh_exec_t, sshd_key_t, sshd_tmp_t;
')
##############################
#
# Declarations
#
type $1_ssh_t;
application_domain($1_ssh_t, ssh_exec_t)
role $3 types $1_ssh_t;
type $1_ssh_home_t;
files_type($1_ssh_home_t)
typealias $1_ssh_home_t alias $1_home_ssh_t;
##############################
#
# Client local policy
#
allow $1_ssh_t self:capability { dac_override dac_read_search setgid setuid };
allow $1_ssh_t self:process { transition signal_perms getsched setsched getsession getpgid setpgid getcap setcap share getattr noatsecure siginh rlimitinh dyntransition setkeycreate setsockcreate getrlimit };
allow $1_ssh_t self:fd use;
allow $1_ssh_t self:fifo_file rw_fifo_file_perms;
allow $1_ssh_t self:unix_dgram_socket { create_socket_perms sendto };
allow $1_ssh_t self:unix_stream_socket { create_stream_socket_perms connectto };
allow $1_ssh_t self:shm create_shm_perms;
allow $1_ssh_t self:sem create_sem_perms;
allow $1_ssh_t self:msgq create_msgq_perms;
allow $1_ssh_t self:msg { send receive };
allow $1_ssh_t self:tcp_socket create_stream_socket_perms;
# for rsync
allow $1_ssh_t $2:unix_stream_socket rw_socket_perms;
allow $1_ssh_t $2:unix_stream_socket connectto;
# Read the ssh key file.
allow $1_ssh_t sshd_key_t:file read_file_perms;
# Access the ssh temporary files.
allow $1_ssh_t sshd_tmp_t:dir manage_dir_perms;
allow $1_ssh_t sshd_tmp_t:file manage_file_perms;
files_tmp_filetrans($1_ssh_t, sshd_tmp_t, { file dir })
# Transition from the domain to the derived domain.
domtrans_pattern($2, ssh_exec_t, $1_ssh_t)
# inheriting stream sockets is needed for "ssh host command" as no pty
# is allocated
# cjp: should probably fix target to be an attribute for ssh servers
# or "regular" (not special like sshd_extern_t) servers
allow $2 ssh_server:unix_stream_socket rw_stream_socket_perms;
# allow ps to show ssh
ps_process_pattern($2, $1_ssh_t)
# user can manage the keys and config
manage_files_pattern($2, $1_ssh_home_t, $1_ssh_home_t)
manage_lnk_files_pattern($2, $1_ssh_home_t, $1_ssh_home_t)
manage_sock_files_pattern($2, $1_ssh_home_t, $1_ssh_home_t)
# ssh client can manage the keys and config
manage_files_pattern($1_ssh_t, $1_ssh_home_t, $1_ssh_home_t)
read_lnk_files_pattern($1_ssh_t, $1_ssh_home_t, $1_ssh_home_t)
# ssh servers can read the user keys and config
allow ssh_server $1_ssh_home_t:dir list_dir_perms;
read_files_pattern(ssh_server, $1_ssh_home_t, $1_ssh_home_t)
read_lnk_files_pattern(ssh_server, $1_ssh_home_t, $1_ssh_home_t)
kernel_read_kernel_sysctls($1_ssh_t)
kernel_read_system_state($1_ssh_t)
corenet_all_recvfrom_unlabeled($1_ssh_t)
corenet_all_recvfrom_netlabel($1_ssh_t)
corenet_tcp_sendrecv_generic_if($1_ssh_t)
corenet_tcp_sendrecv_generic_node($1_ssh_t)
corenet_tcp_sendrecv_all_ports($1_ssh_t)
corenet_tcp_connect_ssh_port($1_ssh_t)
corenet_sendrecv_ssh_client_packets($1_ssh_t)
dev_read_urand($1_ssh_t)
fs_getattr_all_fs($1_ssh_t)
fs_search_auto_mountpoints($1_ssh_t)
# run helper programs - needed eg for x11-ssh-askpass
corecmd_exec_shell($1_ssh_t)
corecmd_exec_bin($1_ssh_t)
domain_use_interactive_fds($1_ssh_t)
files_list_home($1_ssh_t)
files_read_usr_files($1_ssh_t)
files_read_etc_runtime_files($1_ssh_t)
files_read_etc_files($1_ssh_t)
files_read_var_files($1_ssh_t)
auth_use_nsswitch($1_ssh_t)
logging_send_syslog_msg($1_ssh_t)
logging_read_generic_logs($1_ssh_t)
miscfiles_read_localization($1_ssh_t)
seutil_read_config($1_ssh_t)
optional_policy(`
kerberos_use($1_ssh_t)
')
')
#######################################
## <summary>
## The template to define a ssh server.
## </summary>
## <desc>
## <p>
## This template creates a domains to be used for
## creating a ssh server. This is typically done
## to have multiple ssh servers of different sensitivities,
## such as for an internal network-facing ssh server, and
## a external network-facing ssh server.
## </p>
## </desc>
## <param name="userdomain_prefix">
## <summary>
## The prefix of the server domain (e.g., sshd
## is the prefix for sshd_t).
## </summary>
## </param>
#
template(`ssh_server_template', `
type $1_t, ssh_server;
auth_login_pgm_domain($1_t)
type $1_devpts_t;
term_login_pty($1_devpts_t)
type $1_tmpfs_t;
files_tmpfs_file($1_tmpfs_t)
type $1_var_run_t;
files_pid_file($1_var_run_t)
allow $1_t self:capability { chown dac_read_search fowner fsetid kill setgid setuid sys_chroot sys_nice sys_resource sys_tty_config };
# net_admin is for SO_SNDBUFFORCE
dontaudit $1_t self:capability net_admin;
allow $1_t self:fifo_file rw_fifo_file_perms;
allow $1_t self:process { signal getsched setsched setrlimit setexec setkeycreate };
allow $1_t self:tcp_socket create_stream_socket_perms;
allow $1_t self:udp_socket create_socket_perms;
# ssh agent connections:
allow $1_t self:unix_stream_socket create_stream_socket_perms;
allow $1_t self:shm create_shm_perms;
allow $1_t $1_devpts_t:chr_file { rw_chr_file_perms setattr getattr relabelfrom };
term_create_pty($1_t, $1_devpts_t)
manage_files_pattern($1_t, $1_tmpfs_t, $1_tmpfs_t)
fs_tmpfs_filetrans($1_t, $1_tmpfs_t, file)
allow $1_t $1_var_run_t:dir search_dir_perms;
allow $1_t $1_var_run_t:file manage_file_perms;
files_pid_filetrans($1_t, $1_var_run_t, file)
can_exec($1_t, sshd_exec_t)
# Access key files
allow $1_t sshd_key_t:file read_file_perms;
kernel_read_kernel_sysctls($1_t)
kernel_read_network_state($1_t)
corenet_all_recvfrom_unlabeled($1_t)
corenet_all_recvfrom_netlabel($1_t)
corenet_tcp_sendrecv_generic_if($1_t)
corenet_udp_sendrecv_generic_if($1_t)
corenet_raw_sendrecv_generic_if($1_t)
corenet_tcp_sendrecv_generic_node($1_t)
corenet_udp_sendrecv_generic_node($1_t)
corenet_raw_sendrecv_generic_node($1_t)
corenet_udp_sendrecv_all_ports($1_t)
corenet_tcp_sendrecv_all_ports($1_t)
corenet_tcp_bind_generic_node($1_t)
corenet_udp_bind_generic_node($1_t)
corenet_tcp_bind_ssh_port($1_t)
corenet_tcp_connect_all_ports($1_t)
corenet_sendrecv_ssh_server_packets($1_t)
fs_dontaudit_getattr_all_fs($1_t)
auth_rw_login_records($1_t)
auth_rw_faillog($1_t)
# for sshd subsystems, such as sftp-server.
corecmd_getattr_bin_files($1_t)
domain_interactive_fd($1_t)
files_read_etc_files($1_t)
files_read_etc_runtime_files($1_t)
files_read_usr_files($1_t)
logging_search_logs($1_t)
miscfiles_read_localization($1_t)
userdom_create_all_users_keys($1_t)
userdom_dontaudit_relabelfrom_user_ptys($1_t)
userdom_search_user_home_dirs($1_t)
# Allow checking users mail at login
optional_policy(`
mta_getattr_spool($1_t)
')
tunable_policy(`use_nfs_home_dirs',`
fs_read_nfs_files($1_t)
fs_read_nfs_symlinks($1_t)
')
tunable_policy(`use_samba_home_dirs',`
fs_read_cifs_files($1_t)
')
optional_policy(`
kerberos_use($1_t)
kerberos_manage_host_rcache($1_t)
')
optional_policy(`
files_read_var_lib_symlinks($1_t)
nx_spec_domtrans_server($1_t)
')
optional_policy(`
systemd_read_logind_sessions_files($1_t)
')
')
########################################
## <summary>
## Role access for ssh
## </summary>
## <param name="role_prefix">
## <summary>
## The prefix of the role (e.g., user
## is the prefix for user_r).
## </summary>
## </param>
## <param name="role">
## <summary>
## Role allowed access
## </summary>
## </param>
## <param name="domain">
## <summary>
## User domain for the role
## </summary>
## </param>
#
template(`ssh_role_template',`
gen_require(`
attribute ssh_server, ssh_agent_type;
type ssh_t, ssh_exec_t, ssh_tmpfs_t, ssh_home_t;
type ssh_agent_exec_t, ssh_keysign_t, ssh_tmpfs_t;
type ssh_agent_tmp_t;
')
##############################
#
# Declarations
#
role $2 types ssh_t;
type $1_ssh_agent_t, ssh_agent_type;
userdom_user_application_domain($1_ssh_agent_t, ssh_agent_exec_t)
domain_interactive_fd($1_ssh_agent_t)
role $2 types $1_ssh_agent_t;
##############################
#
# Local policy
#
# Transition from the domain to the derived domain.
domtrans_pattern($3, ssh_exec_t, ssh_t)
# inheriting stream sockets is needed for "ssh host command" as no pty
# is allocated
allow $3 ssh_server:unix_stream_socket rw_stream_socket_perms;
# allow ps to show ssh
ps_process_pattern($3, ssh_t)
allow $3 ssh_t:process signal;
# for rsync
allow ssh_t $3:unix_stream_socket rw_socket_perms;
allow ssh_t $3:unix_stream_socket connectto;
allow ssh_t $3:key manage_key_perms;
# user can manage the keys and config
manage_files_pattern($3, ssh_home_t, ssh_home_t)
manage_lnk_files_pattern($3, ssh_home_t, ssh_home_t)
manage_sock_files_pattern($3, ssh_home_t, ssh_home_t)
userdom_search_user_home_dirs($1_t)
##############################
#
# SSH agent local policy
#
allow $1_ssh_agent_t self:process { setrlimit signal };
allow $1_ssh_agent_t self:capability setgid;
allow $1_ssh_agent_t self:fifo_file rw_file_perms;
allow $1_ssh_agent_t { $1_ssh_agent_t $3 }:process signull;
allow $1_ssh_agent_t self:unix_stream_socket { create_stream_socket_perms connectto };
manage_dirs_pattern($1_ssh_agent_t, ssh_agent_tmp_t, ssh_agent_tmp_t)
manage_sock_files_pattern($1_ssh_agent_t, ssh_agent_tmp_t, ssh_agent_tmp_t)
files_tmp_filetrans($1_ssh_agent_t, ssh_agent_tmp_t, { dir sock_file })
# for ssh-add
stream_connect_pattern($3, ssh_agent_tmp_t, ssh_agent_tmp_t, $1_ssh_agent_t)
# Allow the user shell to signal the ssh program.
allow $3 $1_ssh_agent_t:process signal;
# allow ps to show ssh
ps_process_pattern($3, $1_ssh_agent_t)
domtrans_pattern($3, ssh_agent_exec_t, $1_ssh_agent_t)
kernel_read_kernel_sysctls($1_ssh_agent_t)
dev_read_urand($1_ssh_agent_t)
dev_read_rand($1_ssh_agent_t)
fs_search_auto_mountpoints($1_ssh_agent_t)
# transition back to normal privs upon exec
corecmd_shell_domtrans($1_ssh_agent_t, $3)
corecmd_bin_domtrans($1_ssh_agent_t, $3)
domain_use_interactive_fds($1_ssh_agent_t)
files_read_etc_files($1_ssh_agent_t)
files_read_etc_runtime_files($1_ssh_agent_t)
files_search_home($1_ssh_agent_t)
libs_read_lib_files($1_ssh_agent_t)
logging_send_syslog_msg($1_ssh_agent_t)
miscfiles_read_localization($1_ssh_agent_t)
miscfiles_read_generic_certs($1_ssh_agent_t)
seutil_dontaudit_read_config($1_ssh_agent_t)
# Write to the user domain tty.
userdom_use_user_terminals($1_ssh_agent_t)
# for the transition back to normal privs upon exec
userdom_search_user_home_content($1_ssh_agent_t)
userdom_user_home_domtrans($1_ssh_agent_t, $3)
allow $3 $1_ssh_agent_t:fd use;
allow $3 $1_ssh_agent_t:fifo_file rw_file_perms;
allow $3 $1_ssh_agent_t:process sigchld;
tunable_policy(`use_nfs_home_dirs',`
fs_manage_nfs_files($1_ssh_agent_t)
# transition back to normal privs upon exec
fs_nfs_domtrans($1_ssh_agent_t, $3)
')
tunable_policy(`use_samba_home_dirs',`
fs_manage_cifs_files($1_ssh_agent_t)
# transition back to normal privs upon exec
fs_cifs_domtrans($1_ssh_agent_t, $3)
')
optional_policy(`
nis_use_ypbind($1_ssh_agent_t)
')
optional_policy(`
tunable_policy(`ssh_use_gpg_agent',`
# for ssh-add
gpg_stream_connect_agent($3)
')
')
optional_policy(`
xserver_use_xdm_fds($1_ssh_agent_t)
xserver_rw_xdm_pipes($1_ssh_agent_t)
xserver_sigchld_xdm($1_ssh_agent_t)
')
')
########################################
## <summary>
## Send a SIGCHLD signal to the ssh server.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_sigchld',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:process sigchld;
')
########################################
## <summary>
## Send a generic signal to the ssh server.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_signal',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:process signal;
')
########################################
## <summary>
## Send a null signal to sshd processes.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_signull',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:process signull;
')
########################################
## <summary>
## Read a ssh server unnamed pipe.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_read_pipes',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:fifo_file { getattr read };
')
########################################
## <summary>
## Read and write a ssh server unnamed pipe.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_rw_pipes',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:fifo_file { write read getattr ioctl };
')
########################################
## <summary>
## Read and write ssh server unix domain stream sockets.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_rw_stream_sockets',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:unix_stream_socket rw_stream_socket_perms;
')
########################################
## <summary>
## Read and write ssh server TCP sockets.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_rw_tcp_sockets',`
gen_require(`
type sshd_t;
')
allow $1 sshd_t:tcp_socket rw_stream_socket_perms;
')
########################################
## <summary>
## Do not audit attempts to read and write
## ssh server TCP sockets.
## </summary>
## <param name="domain">
## <summary>
## Domain to not audit.
## </summary>
## </param>
#
interface(`ssh_dontaudit_rw_tcp_sockets',`
gen_require(`
type sshd_t;
')
dontaudit $1 sshd_t:tcp_socket { read write };
')
########################################
## <summary>
## Execute the ssh daemon in the caller domain.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_exec_sshd',`
gen_require(`
type sshd_exec_t;
')
corecmd_search_bin($1)
can_exec($1, sshd_exec_t)
')
########################################
## <summary>
## Execute the ssh daemon sshd domain.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed to transition.
## </summary>
## </param>
#
interface(`ssh_domtrans',`
gen_require(`
type sshd_t, sshd_exec_t;
')
domtrans_pattern($1, sshd_exec_t, sshd_t)
')
########################################
## <summary>
## Execute the ssh client in the caller domain.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_exec',`
gen_require(`
type ssh_exec_t;
')
corecmd_search_bin($1)
can_exec($1, ssh_exec_t)
')
########################################
## <summary>
## Set the attributes of sshd key files.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_setattr_key_files',`
gen_require(`
type sshd_key_t;
')
allow $1 sshd_key_t:file setattr;
files_search_pids($1)
')
########################################
## <summary>
## Execute the ssh agent client in the caller domain.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_agent_exec',`
gen_require(`
type ssh_agent_exec_t;
')
corecmd_search_bin($1)
can_exec($1, ssh_agent_exec_t)
')
########################################
## <summary>
## Read ssh home directory content
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_read_user_home_files',`
gen_require(`
type ssh_home_t;
')
allow $1 ssh_home_t:dir list_dir_perms;
read_files_pattern($1, ssh_home_t, ssh_home_t)
read_lnk_files_pattern($1, ssh_home_t, ssh_home_t)
userdom_search_user_home_dirs($1)
')
########################################
## <summary>
## Execute the ssh key generator in the ssh keygen domain.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed to transition.
## </summary>
## </param>
#
interface(`ssh_domtrans_keygen',`
gen_require(`
type ssh_keygen_t, ssh_keygen_exec_t;
')
domtrans_pattern($1, ssh_keygen_exec_t, ssh_keygen_t)
')
########################################
## <summary>
## Read ssh server keys
## </summary>
## <param name="domain">
## <summary>
## Domain to not audit.
## </summary>
## </param>
#
interface(`ssh_dontaudit_read_server_keys',`
gen_require(`
type sshd_key_t;
')
dontaudit $1 sshd_key_t:file { getattr read };
')
######################################
## <summary>
## Manage ssh home directory content
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_manage_home_files',`
gen_require(`
type ssh_home_t;
')
manage_files_pattern($1, ssh_home_t, ssh_home_t)
userdom_search_user_home_dirs($1)
')
#######################################
## <summary>
## Delete from the ssh temp files.
## </summary>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
interface(`ssh_delete_tmp',`
gen_require(`
type sshd_tmp_t;
')
files_search_tmp($1)
delete_files_pattern($1, sshd_tmp_t, sshd_tmp_t)
')