kprobes: Prevent probes in .noinstr.text section

Instrumentation is forbidden in the .noinstr.text section. Make kprobes respect this. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
sm00th · May 19, 2020 · 66e9b07 · 66e9b07
1 parent 4e321b7
commit 66e9b07
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diff --git a/include/linux/module.h b/include/linux/module.h
@@ -458,6 +458,8 @@ struct module {
 	void __percpu *percpu;
 	unsigned int percpu_size;
 #endif
+	void *noinstr_text_start;
+	unsigned int noinstr_text_size;
 
 #ifdef CONFIG_TRACEPOINTS
 	unsigned int num_tracepoints;

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
@@ -2229,6 +2229,12 @@ 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();
 }
@@ -2248,6 +2254,12 @@ static void add_module_kprobe_blacklist(struct module *mod)
 		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)
@@ -2265,6 +2277,12 @@ static void remove_module_kprobe_blacklist(struct module *mod)
 		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 */

diff --git 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),