1 files changed, 283 insertions, 66 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index fcfb580c3af..1e0250cb948 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -72,6 +72,18 @@ DEFINE_MUTEX(kprobe_mutex);		/* Protects kprobe_table */
 DEFINE_SPINLOCK(kretprobe_lock);	/* Protects kretprobe_inst_table */
 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
 
+/*
+ * Normally, functions that we'd want to prohibit kprobes in, are marked
+ * __kprobes. But, there are cases where such functions already belong to
+ * a different section (__sched for preempt_schedule)
+ *
+ * For such cases, we now have a blacklist
+ */
+struct kprobe_blackpoint kprobe_blacklist[] = {
+	{"preempt_schedule",},
+	{NULL}    /* Terminator */
+};
+
 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 /*
  * kprobe->ainsn.insn points to the copy of the instruction to be
@@ -417,6 +429,21 @@ static inline void free_rp_inst(struct kretprobe *rp)
 	}
 }
 
+static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
+{
+	unsigned long flags;
+	struct kretprobe_instance *ri;
+	struct hlist_node *pos, *next;
+	/* No race here */
+	spin_lock_irqsave(&kretprobe_lock, flags);
+	hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
+		ri->rp = NULL;
+		hlist_del(&ri->uflist);
+	}
+	spin_unlock_irqrestore(&kretprobe_lock, flags);
+	free_rp_inst(rp);
+}
+
 /*
  * Keep all fields in the kprobe consistent
  */
@@ -492,9 +519,22 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
 
 static int __kprobes in_kprobes_functions(unsigned long addr)
 {
+	struct kprobe_blackpoint *kb;
+
 	if (addr >= (unsigned long)__kprobes_text_start &&
 	    addr < (unsigned long)__kprobes_text_end)
 		return -EINVAL;
+	/*
+	 * If there exists a kprobe_blacklist, verify and
+	 * fail any probe registration in the prohibited area
+	 */
+	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+		if (kb->start_addr) {
+			if (addr >= kb->start_addr &&
+			    addr < (kb->start_addr + kb->range))
+				return -EINVAL;
+		}
+	}
 	return 0;
 }
 
@@ -555,6 +595,7 @@ static int __kprobes __register_kprobe(struct kprobe *p,
 	}
 
 	p->nmissed = 0;
+	INIT_LIST_HEAD(&p->list);
 	mutex_lock(&kprobe_mutex);
 	old_p = get_kprobe(p->addr);
 	if (old_p) {
@@ -581,35 +622,28 @@ out:
 	return ret;
 }
 
-int __kprobes register_kprobe(struct kprobe *p)
-{
-	return __register_kprobe(p, (unsigned long)__builtin_return_address(0));
-}
-
-void __kprobes unregister_kprobe(struct kprobe *p)
+/*
+ * Unregister a kprobe without a scheduler synchronization.
+ */
+static int __kprobes __unregister_kprobe_top(struct kprobe *p)
 {
-	struct module *mod;
 	struct kprobe *old_p, *list_p;
-	int cleanup_p;
 
-	mutex_lock(&kprobe_mutex);
 	old_p = get_kprobe(p->addr);
-	if (unlikely(!old_p)) {
-		mutex_unlock(&kprobe_mutex);
-		return;
-	}
+	if (unlikely(!old_p))
+		return -EINVAL;
+
 	if (p != old_p) {
 		list_for_each_entry_rcu(list_p, &old_p->list, list)
 			if (list_p == p)
 			/* kprobe p is a valid probe */
 				goto valid_p;
-		mutex_unlock(&kprobe_mutex);
-		return;
+		return -EINVAL;
 	}
 valid_p:
 	if (old_p == p ||
 	    (old_p->pre_handler == aggr_pre_handler &&
-	     p->list.next == &old_p->list && p->list.prev == &old_p->list)) {
+	     list_is_singular(&old_p->list))) {
 		/*
 		 * Only probe on the hash list. Disarm only if kprobes are
 		 * enabled - otherwise, the breakpoint would already have
@@ -618,43 +652,97 @@ valid_p:
 		if (kprobe_enabled)
 			arch_disarm_kprobe(p);
 		hlist_del_rcu(&old_p->hlist);
-		cleanup_p = 1;
 	} else {
+		if (p->break_handler)
+			old_p->break_handler = NULL;
+		if (p->post_handler) {
+			list_for_each_entry_rcu(list_p, &old_p->list, list) {
+				if ((list_p != p) && (list_p->post_handler))
+					goto noclean;
+			}
+			old_p->post_handler = NULL;
+		}
+noclean:
 		list_del_rcu(&p->list);
-		cleanup_p = 0;
 	}
+	return 0;
+}
 
-	mutex_unlock(&kprobe_mutex);
+static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
+{
+	struct module *mod;
+	struct kprobe *old_p;
 
-	synchronize_sched();
 	if (p->mod_refcounted) {
 		mod = module_text_address((unsigned long)p->addr);
 		if (mod)
 			module_put(mod);
 	}
 
-	if (cleanup_p) {
-		if (p != old_p) {
-			list_del_rcu(&p->list);
+	if (list_empty(&p->list) || list_is_singular(&p->list)) {
+		if (!list_empty(&p->list)) {
+			/* "p" is the last child of an aggr_kprobe */
+			old_p = list_entry(p->list.next, struct kprobe, list);
+			list_del(&p->list);
 			kfree(old_p);
 		}
 		arch_remove_kprobe(p);
-	} else {
-		mutex_lock(&kprobe_mutex);
-		if (p->break_handler)
-			old_p->break_handler = NULL;
-		if (p->post_handler){
-			list_for_each_entry_rcu(list_p, &old_p->list, list){
-				if (list_p->post_handler){
-					cleanup_p = 2;
-					break;
-				}
-			}
-			if (cleanup_p == 0)
-				old_p->post_handler = NULL;
+	}
+}
+
+static int __register_kprobes(struct kprobe **kps, int num,
+	unsigned long called_from)
+{
+	int i, ret = 0;
+
+	if (num <= 0)
+		return -EINVAL;
+	for (i = 0; i < num; i++) {
+		ret = __register_kprobe(kps[i], called_from);
+		if (ret < 0 && i > 0) {
+			unregister_kprobes(kps, i);
+			break;
 		}
-		mutex_unlock(&kprobe_mutex);
 	}
+	return ret;
+}
+
+/*
+ * Registration and unregistration functions for kprobe.
+ */
+int __kprobes register_kprobe(struct kprobe *p)
+{
+	return __register_kprobes(&p, 1,
+				  (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kprobe(struct kprobe *p)
+{
+	unregister_kprobes(&p, 1);
+}
+
+int __kprobes register_kprobes(struct kprobe **kps, int num)
+{
+	return __register_kprobes(kps, num,
+				  (unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kprobes(struct kprobe **kps, int num)
+{
+	int i;
+
+	if (num <= 0)
+		return;
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < num; i++)
+		if (__unregister_kprobe_top(kps[i]) < 0)
+			kps[i]->addr = NULL;
+	mutex_unlock(&kprobe_mutex);
+
+	synchronize_sched();
+	for (i = 0; i < num; i++)
+		if (kps[i]->addr)
+			__unregister_kprobe_bottom(kps[i]);
 }
 
 static struct notifier_block kprobe_exceptions_nb = {
@@ -667,24 +755,69 @@ unsigned long __weak arch_deref_entry_point(void *entry)
 	return (unsigned long)entry;
 }
 
-int __kprobes register_jprobe(struct jprobe *jp)
+static int __register_jprobes(struct jprobe **jps, int num,
+	unsigned long called_from)
 {
-	unsigned long addr = arch_deref_entry_point(jp->entry);
+	struct jprobe *jp;
+	int ret = 0, i;
 
-	if (!kernel_text_address(addr))
+	if (num <= 0)
 		return -EINVAL;
+	for (i = 0; i < num; i++) {
+		unsigned long addr;
+		jp = jps[i];
+		addr = arch_deref_entry_point(jp->entry);
+
+		if (!kernel_text_address(addr))
+			ret = -EINVAL;
+		else {
+			/* Todo: Verify probepoint is a function entry point */
+			jp->kp.pre_handler = setjmp_pre_handler;
+			jp->kp.break_handler = longjmp_break_handler;
+			ret = __register_kprobe(&jp->kp, called_from);
+		}
+		if (ret < 0 && i > 0) {
+			unregister_jprobes(jps, i);
+			break;
+		}
+	}
+	return ret;
+}
 
-	/* Todo: Verify probepoint is a function entry point */
-	jp->kp.pre_handler = setjmp_pre_handler;
-	jp->kp.break_handler = longjmp_break_handler;
-
-	return __register_kprobe(&jp->kp,
+int __kprobes register_jprobe(struct jprobe *jp)
+{
+	return __register_jprobes(&jp, 1,
 		(unsigned long)__builtin_return_address(0));
 }
 
 void __kprobes unregister_jprobe(struct jprobe *jp)
 {
-	unregister_kprobe(&jp->kp);
+	unregister_jprobes(&jp, 1);
+}
+
+int __kprobes register_jprobes(struct jprobe **jps, int num)
+{
+	return __register_jprobes(jps, num,
+		(unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_jprobes(struct jprobe **jps, int num)
+{
+	int i;
+
+	if (num <= 0)
+		return;
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < num; i++)
+		if (__unregister_kprobe_top(&jps[i]->kp) < 0)
+			jps[i]->kp.addr = NULL;
+	mutex_unlock(&kprobe_mutex);
+
+	synchronize_sched();
+	for (i = 0; i < num; i++) {
+		if (jps[i]->kp.addr)
+			__unregister_kprobe_bottom(&jps[i]->kp);
+	}
 }
 
 #ifdef CONFIG_KRETPROBES
@@ -725,7 +858,8 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 	return 0;
 }
 
-int __kprobes register_kretprobe(struct kretprobe *rp)
+static int __kprobes __register_kretprobe(struct kretprobe *rp,
+					  unsigned long called_from)
 {
 	int ret = 0;
 	struct kretprobe_instance *inst;
@@ -771,46 +905,101 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 
 	rp->nmissed = 0;
 	/* Establish function entry probe point */
-	if ((ret = __register_kprobe(&rp->kp,
-		(unsigned long)__builtin_return_address(0))) != 0)
+	ret = __register_kprobe(&rp->kp, called_from);
+	if (ret != 0)
 		free_rp_inst(rp);
 	return ret;
 }
 
+static int __register_kretprobes(struct kretprobe **rps, int num,
+	unsigned long called_from)
+{
+	int ret = 0, i;
+
+	if (num <= 0)
+		return -EINVAL;
+	for (i = 0; i < num; i++) {
+		ret = __register_kretprobe(rps[i], called_from);
+		if (ret < 0 && i > 0) {
+			unregister_kretprobes(rps, i);
+			break;
+		}
+	}
+	return ret;
+}
+
+int __kprobes register_kretprobe(struct kretprobe *rp)
+{
+	return __register_kretprobes(&rp, 1,
+			(unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kretprobe(struct kretprobe *rp)
+{
+	unregister_kretprobes(&rp, 1);
+}
+
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
+{
+	return __register_kretprobes(rps, num,
+			(unsigned long)__builtin_return_address(0));
+}
+
+void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
+{
+	int i;
+
+	if (num <= 0)
+		return;
+	mutex_lock(&kprobe_mutex);
+	for (i = 0; i < num; i++)
+		if (__unregister_kprobe_top(&rps[i]->kp) < 0)
+			rps[i]->kp.addr = NULL;
+	mutex_unlock(&kprobe_mutex);
+
+	synchronize_sched();
+	for (i = 0; i < num; i++) {
+		if (rps[i]->kp.addr) {
+			__unregister_kprobe_bottom(&rps[i]->kp);
+			cleanup_rp_inst(rps[i]);
+		}
+	}
+}
+
 #else /* CONFIG_KRETPROBES */
 int __kprobes register_kretprobe(struct kretprobe *rp)
 {
 	return -ENOSYS;
 }
 
-static int __kprobes pre_handler_kretprobe(struct kprobe *p,
-					   struct pt_regs *regs)
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
 {
-	return 0;
+	return -ENOSYS;
 }
-#endif /* CONFIG_KRETPROBES */
-
 void __kprobes unregister_kretprobe(struct kretprobe *rp)
 {
-	unsigned long flags;
-	struct kretprobe_instance *ri;
-	struct hlist_node *pos, *next;
+}
 
-	unregister_kprobe(&rp->kp);
+void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
+{
+}
 
-	/* No race here */
-	spin_lock_irqsave(&kretprobe_lock, flags);
-	hlist_for_each_entry_safe(ri, pos, next, &rp->used_instances, uflist) {
-		ri->rp = NULL;
-		hlist_del(&ri->uflist);
-	}
-	spin_unlock_irqrestore(&kretprobe_lock, flags);
-	free_rp_inst(rp);
+static int __kprobes pre_handler_kretprobe(struct kprobe *p,
+					   struct pt_regs *regs)
+{
+	return 0;
 }
 
+#endif /* CONFIG_KRETPROBES */
+
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
+	unsigned long offset = 0, size = 0;
+	char *modname, namebuf[128];
+	const char *symbol_name;
+	void *addr;
+	struct kprobe_blackpoint *kb;
 
 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
@@ -819,6 +1008,28 @@ static int __init init_kprobes(void)
 		INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
 	}
 
+	/*
+	 * Lookup and populate the kprobe_blacklist.
+	 *
+	 * Unlike the kretprobe blacklist, we'll need to determine
+	 * the range of addresses that belong to the said functions,
+	 * since a kprobe need not necessarily be at the beginning
+	 * of a function.
+	 */
+	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+		kprobe_lookup_name(kb->name, addr);
+		if (!addr)
+			continue;
+
+		kb->start_addr = (unsigned long)addr;
+		symbol_name = kallsyms_lookup(kb->start_addr,
+				&size, &offset, &modname, namebuf);
+		if (!symbol_name)
+			kb->range = 0;
+		else
+			kb->range = size;
+	}
+
 	if (kretprobe_blacklist_size) {
 		/* lookup the function address from its name */
 		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
@@ -1066,8 +1277,12 @@ module_init(init_kprobes);
 
 EXPORT_SYMBOL_GPL(register_kprobe);
 EXPORT_SYMBOL_GPL(unregister_kprobe);
+EXPORT_SYMBOL_GPL(register_kprobes);
+EXPORT_SYMBOL_GPL(unregister_kprobes);
 EXPORT_SYMBOL_GPL(register_jprobe);
 EXPORT_SYMBOL_GPL(unregister_jprobe);
+EXPORT_SYMBOL_GPL(register_jprobes);
+EXPORT_SYMBOL_GPL(unregister_jprobes);
 #ifdef CONFIG_KPROBES
 EXPORT_SYMBOL_GPL(jprobe_return);
 #endif
@@ -1075,4 +1290,6 @@ EXPORT_SYMBOL_GPL(jprobe_return);
 #ifdef CONFIG_KPROBES
 EXPORT_SYMBOL_GPL(register_kretprobe);
 EXPORT_SYMBOL_GPL(unregister_kretprobe);
+EXPORT_SYMBOL_GPL(register_kretprobes);
+EXPORT_SYMBOL_GPL(unregister_kretprobes);
 #endif