On Friday, April 08, 2016 01:52:00 PM Stephen Smalley wrote:
> Distinguish capability checks against a target associated
> with the init user namespace versus capability checks against
> a target associated with a non-init user namespace by defining
> and using separate security classes for the latter.
>
> This is needed to support e.g. Chrome usage of user namespaces
> for the Chrome sandbox without needing to allow Chrome to also
> exercise capabilities on targets in the init user namespace.
>
> Suggested-by: Dan Walsh <[email protected]>
> Signed-off-by: Stephen Smalley <[email protected]>
> ---
> security/selinux/hooks.c | 14 +++++++-------
> security/selinux/include/classmap.h | 28 ++++++++++++++++++----------
> 2 files changed, 25 insertions(+), 17 deletions(-)
Applied, thanks.
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index fce7dc8..a9ca5ee 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -1622,7 +1622,7 @@ static int current_has_perm(const struct task_struct
> *tsk,
>
> /* Check whether a task is allowed to use a capability. */
> static int cred_has_capability(const struct cred *cred,
> - int cap, int audit)
> + int cap, int audit, bool initns)
> {
> struct common_audit_data ad;
> struct av_decision avd;
> @@ -1636,10 +1636,10 @@ static int cred_has_capability(const struct cred
> *cred,
>
> switch (CAP_TO_INDEX(cap)) {
> case 0:
> - sclass = SECCLASS_CAPABILITY;
> + sclass = initns ? SECCLASS_CAPABILITY : SECCLASS_CAP_USERNS;
> break;
> case 1:
> - sclass = SECCLASS_CAPABILITY2;
> + sclass = initns ? SECCLASS_CAPABILITY2 : SECCLASS_CAP2_USERNS;
> break;
> default:
> printk(KERN_ERR
> @@ -2142,7 +2142,7 @@ static int selinux_capset(struct cred *new, const
> struct cred *old, static int selinux_capable(const struct cred *cred,
> struct user_namespace *ns, int cap, int audit)
> {
> - return cred_has_capability(cred, cap, audit);
> + return cred_has_capability(cred, cap, audit, ns == &init_user_ns);
> }
>
> static int selinux_quotactl(int cmds, int type, int id, struct super_block
> *sb) @@ -2220,7 +2220,7 @@ static int selinux_vm_enough_memory(struct
> mm_struct *mm, long pages) int rc, cap_sys_admin = 0;
>
> rc = cred_has_capability(current_cred(), CAP_SYS_ADMIN,
> - SECURITY_CAP_NOAUDIT);
> + SECURITY_CAP_NOAUDIT, true);
> if (rc == 0)
> cap_sys_admin = 1;
>
> @@ -3201,7 +3201,7 @@ static int selinux_inode_getsecurity(struct inode
> *inode, const char *name, void SECURITY_CAP_NOAUDIT);
> if (!error)
> error = cred_has_capability(current_cred(), CAP_MAC_ADMIN,
> - SECURITY_CAP_NOAUDIT);
> + SECURITY_CAP_NOAUDIT, true);
> if (!error)
> error = security_sid_to_context_force(isec->sid, &context,
> &size);
> @@ -3376,7 +3376,7 @@ static int selinux_file_ioctl(struct file *file,
> unsigned int cmd, case KDSKBENT:
> case KDSKBSENT:
> error = cred_has_capability(cred, CAP_SYS_TTY_CONFIG,
> - SECURITY_CAP_AUDIT);
> + SECURITY_CAP_AUDIT, true);
> break;
>
> /* default case assumes that the command will go
> diff --git a/security/selinux/include/classmap.h
> b/security/selinux/include/classmap.h index 8fbd138..1f1f4b2 100644
> --- a/security/selinux/include/classmap.h
> +++ b/security/selinux/include/classmap.h
> @@ -12,6 +12,18 @@
> #define COMMON_IPC_PERMS "create", "destroy", "getattr", "setattr", "read",
> \ "write", "associate", "unix_read", "unix_write"
>
> +#define COMMON_CAP_PERMS "chown", "dac_override", "dac_read_search", \
> + "fowner", "fsetid", "kill", "setgid", "setuid", "setpcap", \
> + "linux_immutable", "net_bind_service", "net_broadcast", \
> + "net_admin", "net_raw", "ipc_lock", "ipc_owner", "sys_module", \
> + "sys_rawio", "sys_chroot", "sys_ptrace", "sys_pacct", "sys_admin", \
> + "sys_boot", "sys_nice", "sys_resource", "sys_time", \
> + "sys_tty_config", "mknod", "lease", "audit_write", \
> + "audit_control", "setfcap"
> +
> +#define COMMON_CAP2_PERMS "mac_override", "mac_admin", "syslog", \
> + "wake_alarm", "block_suspend", "audit_read"
> +
> /*
> * Note: The name for any socket class should be suffixed by "socket",
> * and doesn't contain more than one substr of "socket".
> @@ -34,14 +46,7 @@ struct security_class_mapping secclass_map[] = {
> { "ipc_info", "syslog_read", "syslog_mod",
> "syslog_console", "module_request", "module_load", NULL } },
> { "capability",
> - { "chown", "dac_override", "dac_read_search",
> - "fowner", "fsetid", "kill", "setgid", "setuid", "setpcap",
> - "linux_immutable", "net_bind_service", "net_broadcast",
> - "net_admin", "net_raw", "ipc_lock", "ipc_owner", "sys_module",
> - "sys_rawio", "sys_chroot", "sys_ptrace", "sys_pacct", "sys_admin",
> - "sys_boot", "sys_nice", "sys_resource", "sys_time",
> - "sys_tty_config", "mknod", "lease", "audit_write",
> - "audit_control", "setfcap", NULL } },
> + { COMMON_CAP_PERMS, NULL } },
> { "filesystem",
> { "mount", "remount", "unmount", "getattr",
> "relabelfrom", "relabelto", "associate", "quotamod",
> @@ -150,12 +155,15 @@ struct security_class_mapping secclass_map[] = {
> { "memprotect", { "mmap_zero", NULL } },
> { "peer", { "recv", NULL } },
> { "capability2",
> - { "mac_override", "mac_admin", "syslog", "wake_alarm",
> "block_suspend",
> - "audit_read", NULL } },
> + { COMMON_CAP2_PERMS, NULL } },
> { "kernel_service", { "use_as_override", "create_files_as", NULL } },
> { "tun_socket",
> { COMMON_SOCK_PERMS, "attach_queue", NULL } },
> { "binder", { "impersonate", "call", "set_context_mgr", "transfer",
> NULL } },
> + { "cap_userns",
> + { COMMON_CAP_PERMS, NULL } },
> + { "cap2_userns",
> + { COMMON_CAP2_PERMS, NULL } },
> { NULL }
> };
--
paul moore
www.paul-moore.com
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