[PATCH v16 1/3] lsm, selinux: Add setup_report permission to binder

[Li Li <dualli@chromium.org>]

From: Thiébaud Weksteen <tweek@google.com>

Introduce a new permission "setup_report" to the "binder" class.
This persmission controls the ability to set up the binder generic
netlink driver to report certain binder transactions.

Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Signed-off-by: Li Li <dualli@google.com>
---
 include/linux/lsm_hook_defs.h       |  1 +
 include/linux/security.h            |  6 ++++++
 security/security.c                 | 13 +++++++++++++
 security/selinux/hooks.c            |  7 +++++++
 security/selinux/include/classmap.h |  3 ++-
 5 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 2bf909fa3394..395528de689f 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -33,6 +33,7 @@ LSM_HOOK(int, 0, binder_transfer_binder, const struct cred *from,
 	 const struct cred *to)
 LSM_HOOK(int, 0, binder_transfer_file, const struct cred *from,
 	 const struct cred *to, const struct file *file)
+LSM_HOOK(int, 0, binder_setup_report, const struct cred *to)
 LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child,
 	 unsigned int mode)
 LSM_HOOK(int, 0, ptrace_traceme, struct task_struct *parent)
diff --git a/include/linux/security.h b/include/linux/security.h
index 1545d515a66b..b3c01254023e 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -338,6 +338,7 @@ int security_binder_transfer_binder(const struct cred *from,
 				    const struct cred *to);
 int security_binder_transfer_file(const struct cred *from,
 				  const struct cred *to, const struct file *file);
+int security_binder_setup_report(const struct cred *to);
 int security_ptrace_access_check(struct task_struct *child, unsigned int mode);
 int security_ptrace_traceme(struct task_struct *parent);
 int security_capget(const struct task_struct *target,
@@ -657,6 +658,11 @@ static inline int security_binder_transfer_file(const struct cred *from,
 	return 0;
 }
 
+static inline int security_binder_setup_report(const struct cred *to)
+{
+	return 0;
+}
+
 static inline int security_ptrace_access_check(struct task_struct *child,
 					     unsigned int mode)
 {
diff --git a/security/security.c b/security/security.c
index 8aa839232c73..382e3bbab215 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1043,6 +1043,19 @@ int security_binder_transfer_file(const struct cred *from,
 	return call_int_hook(binder_transfer_file, from, to, file);
 }
 
+/**
+ * security_binder_setup_report() - Check if process allowed to set up binder reports.
+ * @to: receiving process
+ *
+ * Check whether @to is allowed to set up binder reports.
+ *
+ * Return: Returns 0 if permission is granted.
+ */
+int security_binder_setup_report(const struct cred *to)
+{
+	return call_int_hook(binder_setup_report, to);
+}
+
 /**
  * security_ptrace_access_check() - Check if tracing is allowed
  * @child: target process
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 0d958f38ff9f..2fafa8feafdf 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2092,6 +2092,12 @@ static int selinux_binder_transfer_file(const struct cred *from,
 			    &ad);
 }
 
+static int selinux_binder_setup_report(const struct cred *to)
+{
+	return avc_has_perm(current_sid(), cred_sid(to), SECCLASS_BINDER,
+			    BINDER__SETUP_REPORT, NULL);
+}
+
 static int selinux_ptrace_access_check(struct task_struct *child,
 				       unsigned int mode)
 {
@@ -7217,6 +7223,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(binder_transaction, selinux_binder_transaction),
 	LSM_HOOK_INIT(binder_transfer_binder, selinux_binder_transfer_binder),
 	LSM_HOOK_INIT(binder_transfer_file, selinux_binder_transfer_file),
+	LSM_HOOK_INIT(binder_setup_report, selinux_binder_setup_report),
 
 	LSM_HOOK_INIT(ptrace_access_check, selinux_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, selinux_ptrace_traceme),
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 04a9b480885e..156741f1ca3f 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -135,7 +135,8 @@ const struct security_class_mapping secclass_map[] = {
 	{ "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 } },
+	  { "impersonate", "call", "set_context_mgr", "transfer",
+	    "setup_report", NULL } },
 	{ "cap_userns", { COMMON_CAP_PERMS, NULL } },
 	{ "cap2_userns", { COMMON_CAP2_PERMS, NULL } },
 	{ "sctp_socket",
-- 
2.48.1.711.g2feabab25a-goog