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-rw-r--r--kernel/security/yama/Kconfig9
-rw-r--r--kernel/security/yama/yama_lsm.c76
2 files changed, 23 insertions, 62 deletions
diff --git a/kernel/security/yama/Kconfig b/kernel/security/yama/Kconfig
index 3123e1da2..90c605eea 100644
--- a/kernel/security/yama/Kconfig
+++ b/kernel/security/yama/Kconfig
@@ -6,14 +6,7 @@ config SECURITY_YAMA
This selects Yama, which extends DAC support with additional
system-wide security settings beyond regular Linux discretionary
access controls. Currently available is ptrace scope restriction.
+ Like capabilities, this security module stacks with other LSMs.
Further information can be found in Documentation/security/Yama.txt.
If you are unsure how to answer this question, answer N.
-
-config SECURITY_YAMA_STACKED
- bool "Yama stacked with other LSMs"
- depends on SECURITY_YAMA
- default n
- help
- When Yama is built into the kernel, force it to stack with the
- selected primary LSM.
diff --git a/kernel/security/yama/yama_lsm.c b/kernel/security/yama/yama_lsm.c
index 24aae2ae2..cb6ed1081 100644
--- a/kernel/security/yama/yama_lsm.c
+++ b/kernel/security/yama/yama_lsm.c
@@ -12,7 +12,7 @@
*
*/
-#include <linux/security.h>
+#include <linux/lsm_hooks.h>
#include <linux/sysctl.h>
#include <linux/ptrace.h>
#include <linux/prctl.h>
@@ -154,13 +154,9 @@ void yama_task_free(struct task_struct *task)
int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
- int rc;
+ int rc = -ENOSYS;
struct task_struct *myself = current;
- rc = cap_task_prctl(option, arg2, arg3, arg4, arg5);
- if (rc != -ENOSYS)
- return rc;
-
switch (option) {
case PR_SET_PTRACER:
/* Since a thread can call prctl(), find the group leader
@@ -279,20 +275,13 @@ static int ptracer_exception_found(struct task_struct *tracer,
*
* Returns 0 if following the ptrace is allowed, -ve on error.
*/
-int yama_ptrace_access_check(struct task_struct *child,
+static int yama_ptrace_access_check(struct task_struct *child,
unsigned int mode)
{
- int rc;
-
- /* If standard caps disallows it, so does Yama. We should
- * only tighten restrictions further.
- */
- rc = cap_ptrace_access_check(child, mode);
- if (rc)
- return rc;
+ int rc = 0;
/* require ptrace target be a child of ptracer on attach */
- if (mode == PTRACE_MODE_ATTACH) {
+ if (mode & PTRACE_MODE_ATTACH) {
switch (ptrace_scope) {
case YAMA_SCOPE_DISABLED:
/* No additional restrictions. */
@@ -318,7 +307,7 @@ int yama_ptrace_access_check(struct task_struct *child,
}
}
- if (rc) {
+ if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0) {
printk_ratelimited(KERN_NOTICE
"ptrace of pid %d was attempted by: %s (pid %d)\n",
child->pid, current->comm, current->pid);
@@ -335,14 +324,7 @@ int yama_ptrace_access_check(struct task_struct *child,
*/
int yama_ptrace_traceme(struct task_struct *parent)
{
- int rc;
-
- /* If standard caps disallows it, so does Yama. We should
- * only tighten restrictions further.
- */
- rc = cap_ptrace_traceme(parent);
- if (rc)
- return rc;
+ int rc = 0;
/* Only disallow PTRACE_TRACEME on more aggressive settings. */
switch (ptrace_scope) {
@@ -364,16 +346,12 @@ int yama_ptrace_traceme(struct task_struct *parent)
return rc;
}
-#ifndef CONFIG_SECURITY_YAMA_STACKED
-static struct security_operations yama_ops = {
- .name = "yama",
-
- .ptrace_access_check = yama_ptrace_access_check,
- .ptrace_traceme = yama_ptrace_traceme,
- .task_prctl = yama_task_prctl,
- .task_free = yama_task_free,
+static struct security_hook_list yama_hooks[] = {
+ LSM_HOOK_INIT(ptrace_access_check, yama_ptrace_access_check),
+ LSM_HOOK_INIT(ptrace_traceme, yama_ptrace_traceme),
+ LSM_HOOK_INIT(task_prctl, yama_task_prctl),
+ LSM_HOOK_INIT(task_free, yama_task_free),
};
-#endif
#ifdef CONFIG_SYSCTL
static int yama_dointvec_minmax(struct ctl_table *table, int write,
@@ -413,28 +391,18 @@ static struct ctl_table yama_sysctl_table[] = {
},
{ }
};
-#endif /* CONFIG_SYSCTL */
-
-static __init int yama_init(void)
+static void __init yama_init_sysctl(void)
{
-#ifndef CONFIG_SECURITY_YAMA_STACKED
- if (!security_module_enable(&yama_ops))
- return 0;
-#endif
-
- printk(KERN_INFO "Yama: becoming mindful.\n");
-
-#ifndef CONFIG_SECURITY_YAMA_STACKED
- if (register_security(&yama_ops))
- panic("Yama: kernel registration failed.\n");
-#endif
-
-#ifdef CONFIG_SYSCTL
if (!register_sysctl_paths(yama_sysctl_path, yama_sysctl_table))
panic("Yama: sysctl registration failed.\n");
-#endif
-
- return 0;
}
+#else
+static inline void yama_init_sysctl(void) { }
+#endif /* CONFIG_SYSCTL */
-security_initcall(yama_init);
+void __init yama_add_hooks(void)
+{
+ pr_info("Yama: becoming mindful.\n");
+ security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks));
+ yama_init_sysctl();
+}