2020-05-05 14:26:40

by Thomas Gleixner

[permalink] [raw]
Subject: [patch V4 part 1 16/36] kprobes: Support __kprobes blacklist in modules

From: Masami Hiramatsu <[email protected]>

Support __kprobes attribute for blacklist functions in modules. The
__kprobes attribute functions are stored in .kprobes.text section.

Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/158523418821.24735.15379873028352411526.stgit@devnote2

---
include/linux/module.h | 4 ++++
kernel/kprobes.c | 42 ++++++++++++++++++++++++++++++++++++++++++
kernel/module.c | 4 ++++
3 files changed, 50 insertions(+)

--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -489,6 +489,10 @@ struct module {
unsigned int num_ftrace_callsites;
unsigned long *ftrace_callsites;
#endif
+#ifdef CONFIG_KPROBES
+ void *kprobes_text_start;
+ unsigned int kprobes_text_size;
+#endif

#ifdef CONFIG_LIVEPATCH
bool klp; /* Is this a livepatch module? */
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2179,6 +2179,19 @@ int kprobe_add_area_blacklist(unsigned l
return 0;
}

+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+ struct kprobe_blacklist_entry *ent, *n;
+
+ list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+ if (ent->start_addr < start || ent->start_addr >= end)
+ continue;
+ list_del(&ent->list);
+ kfree(ent);
+ }
+}
+
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
@@ -2215,6 +2228,28 @@ static int __init populate_kprobe_blackl
return ret ? : arch_populate_kprobe_blacklist();
}

+static void add_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+}
+
/* Module notifier call back, checking kprobes on the module */
static int kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
@@ -2225,6 +2260,11 @@ static int kprobes_module_callback(struc
unsigned int i;
int checkcore = (val == MODULE_STATE_GOING);

+ if (val == MODULE_STATE_COMING) {
+ mutex_lock(&kprobe_mutex);
+ add_module_kprobe_blacklist(mod);
+ mutex_unlock(&kprobe_mutex);
+ }
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE;

@@ -2255,6 +2295,8 @@ static int kprobes_module_callback(struc
kill_kprobe(p);
}
}
+ if (val == MODULE_STATE_GOING)
+ remove_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex);
return NOTIFY_DONE;
}
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3194,6 +3194,10 @@ static int find_module_sections(struct m
sizeof(*mod->ei_funcs),
&mod->num_ei_funcs);
#endif
+#ifdef CONFIG_KPROBES
+ mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
+ &mod->kprobes_text_size);
+#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);



2020-05-06 23:18:02

by Alexandre Chartre

[permalink] [raw]
Subject: Re: [patch V4 part 1 16/36] kprobes: Support __kprobes blacklist in modules


On 5/5/20 3:16 PM, Thomas Gleixner wrote:
> From: Masami Hiramatsu <[email protected]>
>
> Support __kprobes attribute for blacklist functions in modules. The
> __kprobes attribute functions are stored in .kprobes.text section.
>
> Signed-off-by: Masami Hiramatsu <[email protected]>
> Signed-off-by: Thomas Gleixner <[email protected]>
> Link: https://lkml.kernel.org/r/158523418821.24735.15379873028352411526.stgit@devnote2
>
> ---
> include/linux/module.h | 4 ++++
> kernel/kprobes.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> kernel/module.c | 4 ++++
> 3 files changed, 50 insertions(+)

Reviewed-by: Alexandre Chartre <[email protected]>

alex.

> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -489,6 +489,10 @@ struct module {
> unsigned int num_ftrace_callsites;
> unsigned long *ftrace_callsites;
> #endif
> +#ifdef CONFIG_KPROBES
> + void *kprobes_text_start;
> + unsigned int kprobes_text_size;
> +#endif
>
> #ifdef CONFIG_LIVEPATCH
> bool klp; /* Is this a livepatch module? */
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -2179,6 +2179,19 @@ int kprobe_add_area_blacklist(unsigned l
> return 0;
> }
>
> +/* Remove all symbols in given area from kprobe blacklist */
> +static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
> +{
> + struct kprobe_blacklist_entry *ent, *n;
> +
> + list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
> + if (ent->start_addr < start || ent->start_addr >= end)
> + continue;
> + list_del(&ent->list);
> + kfree(ent);
> + }
> +}
> +
> int __init __weak arch_populate_kprobe_blacklist(void)
> {
> return 0;
> @@ -2215,6 +2228,28 @@ static int __init populate_kprobe_blackl
> return ret ? : arch_populate_kprobe_blacklist();
> }
>
> +static void add_module_kprobe_blacklist(struct module *mod)
> +{
> + unsigned long start, end;
> +
> + start = (unsigned long)mod->kprobes_text_start;
> + if (start) {
> + end = start + mod->kprobes_text_size;
> + kprobe_add_area_blacklist(start, end);
> + }
> +}
> +
> +static void remove_module_kprobe_blacklist(struct module *mod)
> +{
> + unsigned long start, end;
> +
> + start = (unsigned long)mod->kprobes_text_start;
> + if (start) {
> + end = start + mod->kprobes_text_size;
> + kprobe_remove_area_blacklist(start, end);
> + }
> +}
> +
> /* Module notifier call back, checking kprobes on the module */
> static int kprobes_module_callback(struct notifier_block *nb,
> unsigned long val, void *data)
> @@ -2225,6 +2260,11 @@ static int kprobes_module_callback(struc
> unsigned int i;
> int checkcore = (val == MODULE_STATE_GOING);
>
> + if (val == MODULE_STATE_COMING) {
> + mutex_lock(&kprobe_mutex);
> + add_module_kprobe_blacklist(mod);
> + mutex_unlock(&kprobe_mutex);
> + }
> if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
> return NOTIFY_DONE;
>
> @@ -2255,6 +2295,8 @@ static int kprobes_module_callback(struc
> kill_kprobe(p);
> }
> }
> + if (val == MODULE_STATE_GOING)
> + remove_module_kprobe_blacklist(mod);
> mutex_unlock(&kprobe_mutex);
> return NOTIFY_DONE;
> }
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3194,6 +3194,10 @@ static int find_module_sections(struct m
> sizeof(*mod->ei_funcs),
> &mod->num_ei_funcs);
> #endif
> +#ifdef CONFIG_KPROBES
> + mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
> + &mod->kprobes_text_size);
> +#endif
> mod->extable = section_objs(info, "__ex_table",
> sizeof(*mod->extable), &mod->num_exentries);
>
>

Subject: [tip: core/kprobes] kprobes: Support __kprobes blacklist in modules

The following commit has been merged into the core/kprobes branch of tip:

Commit-ID: 1e6769b0aece51ea7a3dc3117c37d4a5669e4a21
Gitweb: https://git.kernel.org/tip/1e6769b0aece51ea7a3dc3117c37d4a5669e4a21
Author: Masami Hiramatsu <[email protected]>
AuthorDate: Thu, 26 Mar 2020 23:49:48 +09:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Tue, 12 May 2020 17:15:32 +02:00

kprobes: Support __kprobes blacklist in modules

Support __kprobes attribute for blacklist functions in modules. The
__kprobes attribute functions are stored in .kprobes.text section.

Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexandre Chartre <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

---
include/linux/module.h | 4 ++++-
kernel/kprobes.c | 42 +++++++++++++++++++++++++++++++++++++++++-
kernel/module.c | 4 ++++-
3 files changed, 50 insertions(+)

diff --git a/include/linux/module.h b/include/linux/module.h
index 1ad393e..369c354 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -489,6 +489,10 @@ struct module {
unsigned int num_ftrace_callsites;
unsigned long *ftrace_callsites;
#endif
+#ifdef CONFIG_KPROBES
+ void *kprobes_text_start;
+ unsigned int kprobes_text_size;
+#endif

#ifdef CONFIG_LIVEPATCH
bool klp; /* Is this a livepatch module? */
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 570d608..b754999 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2179,6 +2179,19 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
return 0;
}

+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+ struct kprobe_blacklist_entry *ent, *n;
+
+ list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+ if (ent->start_addr < start || ent->start_addr >= end)
+ continue;
+ list_del(&ent->list);
+ kfree(ent);
+ }
+}
+
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
@@ -2215,6 +2228,28 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret ? : arch_populate_kprobe_blacklist();
}

+static void add_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+}
+
/* Module notifier call back, checking kprobes on the module */
static int kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
@@ -2225,6 +2260,11 @@ static int kprobes_module_callback(struct notifier_block *nb,
unsigned int i;
int checkcore = (val == MODULE_STATE_GOING);

+ if (val == MODULE_STATE_COMING) {
+ mutex_lock(&kprobe_mutex);
+ add_module_kprobe_blacklist(mod);
+ mutex_unlock(&kprobe_mutex);
+ }
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE;

@@ -2255,6 +2295,8 @@ static int kprobes_module_callback(struct notifier_block *nb,
kill_kprobe(p);
}
}
+ if (val == MODULE_STATE_GOING)
+ remove_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex);
return NOTIFY_DONE;
}
diff --git a/kernel/module.c b/kernel/module.c
index 646f1e2..978f3fa 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3194,6 +3194,10 @@ static int find_module_sections(struct module *mod, struct load_info *info)
sizeof(*mod->ei_funcs),
&mod->num_ei_funcs);
#endif
+#ifdef CONFIG_KPROBES
+ mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
+ &mod->kprobes_text_size);
+#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);