kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot

BugLink: https://bugs.launchpad.net/bugs/1900624
commit 82d083ab60c3693201c6f5c7a5f23a6ed422098d upstream.

Since kprobe_event= cmdline option allows user to put kprobes on the
functions in initmem, kprobe has to make such probes gone after boot.
Currently the probes on the init functions in modules will be handled
by module callback, but the kernel init text isn't handled.
Without this, kprobes may access non-exist text area to disable or
remove it.

Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2
Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Ian May <ian.may@canonical.com>

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 645fd401c856d4cb5f7cbc34db029abd32b62dfc..a60488867dd066820b0c2e0fdccfee7cd4864b25 100644 (file)
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -369,6 +369,8 @@ void unregister_kretprobes(struct kretprobe **rps, int num);
 void kprobe_flush_task(struct task_struct *tk);
 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 
+void kprobe_free_init_mem(void);
+
 int disable_kprobe(struct kprobe *kp);
 int enable_kprobe(struct kprobe *kp);
 
@@ -426,6 +428,9 @@ static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 static inline void kprobe_flush_task(struct task_struct *tk)
 {
 }
+static inline void kprobe_free_init_mem(void)
+{
+}
 static inline int disable_kprobe(struct kprobe *kp)
 {
        return -ENOSYS;

diff --git a/init/main.c b/init/main.c
index 825244b3e0d51b42030d26237eedc0633a9cadf8..87dab8d9527847c2d7c92e6b1f26881f2fe1a072 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -32,6 +32,7 @@
 #include <linux/nmi.h>
 #include <linux/percpu.h>
 #include <linux/kmod.h>
+#include <linux/kprobes.h>
 #include <linux/vmalloc.h>
 #include <linux/kernel_stat.h>
 #include <linux/start_kernel.h>
@@ -1111,6 +1112,7 @@ static int __ref kernel_init(void *unused)
        kernel_init_freeable();
        /* need to finish all async __init code before freeing the memory */
        async_synchronize_full();
+       kprobe_free_init_mem();
        ftrace_free_init_mem();
        free_initmem();
        mark_readonly();

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8ec7e7c43df5bac271fee069dd34683b7798446b..283c8b01ce78926953d449ff9d6f438494fe9af2 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2320,6 +2320,28 @@ static struct notifier_block kprobe_module_nb = {
 extern unsigned long __start_kprobe_blacklist[];
 extern unsigned long __stop_kprobe_blacklist[];
 
+void kprobe_free_init_mem(void)
+{
+       void *start = (void *)(&__init_begin);
+       void *end = (void *)(&__init_end);
+       struct hlist_head *head;
+       struct kprobe *p;
+       int i;
+
+       mutex_lock(&kprobe_mutex);
+
+       /* Kill all kprobes on initmem */
+       for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+               head = &kprobe_table[i];
+               hlist_for_each_entry(p, head, hlist) {
+                       if (start <= (void *)p->addr && (void *)p->addr < end)
+                               kill_kprobe(p);
+               }
+       }
+
+       mutex_unlock(&kprobe_mutex);
+}
+
 static int __init init_kprobes(void)
 {
        int i, err = 0;