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kprobes: Support __kprobes blacklist in modules

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

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134059.678201813@linutronix.de
This commit is contained in:
Masami Hiramatsu 2020-03-26 23:49:48 +09:00 committed by Thomas Gleixner
parent 4fdd88877e
commit 1e6769b0ae
3 changed files with 50 additions and 0 deletions
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4
include/linux/module.h
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@ -489,6 +489,10 @@ struct module {
unsigned int num_ftrace_callsites; unsigned int num_ftrace_callsites;
unsigned long *ftrace_callsites; unsigned long *ftrace_callsites;
#endif #endif
#ifdef CONFIG_KPROBES
void *kprobes_text_start;
unsigned int kprobes_text_size;
#endif
#ifdef CONFIG_LIVEPATCH #ifdef CONFIG_LIVEPATCH
bool klp; /* Is this a livepatch module? */ bool klp; /* Is this a livepatch module? */

42
kernel/kprobes.c
View File

@ -2179,6 +2179,19 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
return 0; 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) int __init __weak arch_populate_kprobe_blacklist(void)
{ {
return 0; return 0;
@ -2215,6 +2228,28 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret ? : arch_populate_kprobe_blacklist(); 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 */ /* Module notifier call back, checking kprobes on the module */
static int kprobes_module_callback(struct notifier_block *nb, static int kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data) unsigned long val, void *data)
@ -2225,6 +2260,11 @@ static int kprobes_module_callback(struct notifier_block *nb,
unsigned int i; unsigned int i;
int checkcore = (val == MODULE_STATE_GOING); 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) if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE; return NOTIFY_DONE;
@ -2255,6 +2295,8 @@ static int kprobes_module_callback(struct notifier_block *nb,
kill_kprobe(p); kill_kprobe(p);
} }
} }
if (val == MODULE_STATE_GOING)
remove_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex); mutex_unlock(&kprobe_mutex);
return NOTIFY_DONE; return NOTIFY_DONE;
} }

4
kernel/module.c
View File

@ -3193,6 +3193,10 @@ static int find_module_sections(struct module *mod, struct load_info *info)
mod->ei_funcs = section_objs(info, "_error_injection_whitelist", mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
sizeof(*mod->ei_funcs), sizeof(*mod->ei_funcs),
&mod->num_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 #endif
mod->extable = section_objs(info, "__ex_table", mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries); sizeof(*mod->extable), &mod->num_exentries);