[tip: core/kprobes] kprobes: Prevent probes in .noinstr.text section

tip-bot2 for Thomas Gleixner
2020-05-19T19:52:52Z

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

Commit-ID: 66e9b0717102507e64f638790eaece88765cc9e5
Gitweb: https://git.kernel.org/tip/66e9b0717102507e64f638790eaece88765cc9e5
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 10 Mar 2020 14:04:34 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 19 May 2020 15:56:20 +02:00

kprobes: Prevent probes in .noinstr.text section

Instrumentation is forbidden in the .noinstr.text section. Make kprobes
respect this.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200505134100.179862032@linutronix.de

---
include/linux/module.h | 2 ++
kernel/kprobes.c | 18 ++++++++++++++++++
kernel/module.c | 3 +++
3 files changed, 23 insertions(+)

diff --git a/include/linux/module.h b/include/linux/module.h
index 1192097..d849d06 100644
--- 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
index 9eb5acf..3f310df 100644
--- 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
index faf7337..72ed2b3 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),