| Subject | Re: [patch V4 part 1 16/36] kprobes: Support __kprobes blacklist in modules | From | Alexandre Chartre <> | Date | Wed, 6 May 2020 17:47:36 +0200 |
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On 5/5/20 3:16 PM, Thomas Gleixner wrote: > From: Masami Hiramatsu <mhiramat@kernel.org> > > 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> > 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 <alexandre.chartre@oracle.com>
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); > >
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