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authorLinus Torvalds <torvalds@linux-foundation.org>2020-06-01 12:45:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-01 12:45:04 -0700
commit0bd957eb11cfeef23fcc240edde6dfe431731e69 (patch)
treeb230aaa22c06daca90acef99decbbd1709497c4d /kernel
parent9bf9511e3d9f328c03f6f79bfb741c3d18f2f2c0 (diff)
parent66e9b0717102507e64f638790eaece88765cc9e5 (diff)
downloadlinux-0bd957eb11cfeef23fcc240edde6dfe431731e69.tar.bz2
Merge tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull kprobes updates from Ingo Molnar: "Various kprobes updates, mostly centered around cleaning up the no-instrumentation logic. Instead of the current per debug facility blacklist, use the more generic .noinstr.text approach, combined with a 'noinstr' marker for functions. Also add instrumentation_begin()/end() to better manage the exact place in entry code where instrumentation may be used. And add a kprobes blacklist for modules" * tag 'core-kprobes-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes: Prevent probes in .noinstr.text section vmlinux.lds.h: Create section for protection against instrumentation samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers. kprobes: Support NOKPROBE_SYMBOL() in modules kprobes: Support __kprobes blacklist in modules kprobes: Lock kprobe_mutex while showing kprobe_blacklist
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c85
-rw-r--r--kernel/module.c10
2 files changed, 94 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2625c241ac00..3f310df4a693 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2179,6 +2179,24 @@ 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);
+ }
+}
+
+static void kprobe_remove_ksym_blacklist(unsigned long entry)
+{
+ kprobe_remove_area_blacklist(entry, entry + 1);
+}
+
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
@@ -2211,10 +2229,62 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
/* Symbols in __kprobes_text are blacklisted */
ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
(unsigned long)__kprobes_text_end);
+ if (ret)
+ return ret;
+
+ /* Symbols in noinstr section are blacklisted */
+ ret = kprobe_add_area_blacklist((unsigned long)__noinstr_text_start,
+ (unsigned long)__noinstr_text_end);
return ret ? : arch_populate_kprobe_blacklist();
}
+static void add_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+
+ start = (unsigned long)mod->noinstr_text_start;
+ if (start) {
+ end = start + mod->noinstr_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+
+ start = (unsigned long)mod->noinstr_text_start;
+ if (start) {
+ end = start + mod->noinstr_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 +2295,11 @@ 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 +2330,8 @@ 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;
}
@@ -2420,6 +2497,7 @@ static const struct file_operations debugfs_kprobes_operations = {
/* kprobes/blacklist -- shows which functions can not be probed */
static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
{
+ mutex_lock(&kprobe_mutex);
return seq_list_start(&kprobe_blacklist, *pos);
}
@@ -2446,10 +2524,15 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
return 0;
}
+static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
+{
+ mutex_unlock(&kprobe_mutex);
+}
+
static const struct seq_operations kprobe_blacklist_seq_ops = {
.start = kprobe_blacklist_seq_start,
.next = kprobe_blacklist_seq_next,
- .stop = kprobe_seq_stop, /* Reuse void function */
+ .stop = kprobe_blacklist_seq_stop,
.show = kprobe_blacklist_seq_show,
};
diff --git a/kernel/module.c b/kernel/module.c
index 646f1e2330d2..72ed2b3a6ee2 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3150,6 +3150,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
}
#endif
+ mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
+ &mod->noinstr_text_size);
+
#ifdef CONFIG_TRACEPOINTS
mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
sizeof(*mod->tracepoints_ptrs),
@@ -3194,6 +3197,13 @@ 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);
+ mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
+ sizeof(unsigned long),
+ &mod->num_kprobe_blacklist);
+#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);