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Subject[PATCH -tip v8 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text
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Date
Use kprobe_blackpoint for blacklisting .entry.text and .kprobees.text
instead of arch_within_kprobe_blacklist. This also makes them visible
via (debugfs)/kprobes/blacklist.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
arch/x86/kernel/kprobes/core.c | 11 +------
include/linux/kprobes.h | 1 +
kernel/kprobes.c | 64 ++++++++++++++++++++++++++++------------
3 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index d00103a..4767fda 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1065,17 +1065,10 @@ int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
}
NOKPROBE_SYMBOL(longjmp_break_handler);

-bool arch_within_kprobe_blacklist(unsigned long addr)
-{
- return (addr >= (unsigned long)__kprobes_text_start &&
- addr < (unsigned long)__kprobes_text_end) ||
- (addr >= (unsigned long)__entry_text_start &&
- addr < (unsigned long)__entry_text_end);
-}
-
int __init arch_init_kprobes(void)
{
- return 0;
+ return kprobe_blacklist_add_range((unsigned long)__entry_text_start,
+ (unsigned long) __entry_text_end);
}

int arch_trampoline_kprobe(struct kprobe *p)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index e059507..e81bced 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -266,6 +266,7 @@ extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
extern bool arch_within_kprobe_blacklist(unsigned long addr);
+extern int kprobe_blacklist_add_range(unsigned long start, unsigned long end);

struct kprobe_insn_cache {
struct mutex mutex;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8319048..abdede5 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1325,13 +1325,6 @@ out:
return ret;
}

-bool __weak arch_within_kprobe_blacklist(unsigned long addr)
-{
- /* The __kprobes marked functions and entry code must not be probed */
- return addr >= (unsigned long)__kprobes_text_start &&
- addr < (unsigned long)__kprobes_text_end;
-}
-
static struct kprobe_blacklist_entry *find_blacklist_entry(unsigned long addr)
{
struct kprobe_blacklist_entry *ent;
@@ -1346,8 +1339,6 @@ static struct kprobe_blacklist_entry *find_blacklist_entry(unsigned long addr)

static bool within_kprobe_blacklist(unsigned long addr)
{
- if (arch_within_kprobe_blacklist(addr))
- return true;
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -2032,6 +2023,40 @@ void dump_kprobe(struct kprobe *kp)
}
NOKPROBE_SYMBOL(dump_kprobe);

+static int __kprobe_blacklist_add(unsigned long start, unsigned long end)
+{
+ struct kprobe_blacklist_entry *ent;
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+
+ ent->start_addr = start;
+ ent->end_addr = end;
+ INIT_LIST_HEAD(&ent->list);
+ list_add_tail(&ent->list, &kprobe_blacklist);
+ return 0;
+}
+
+int kprobe_blacklist_add_range(unsigned long start, unsigned long end)
+{
+ unsigned long offset = 0, size = 0;
+ int err = 0;
+
+ mutex_lock(&kprobe_blacklist_mutex);
+ while (!err && start < end) {
+ if (!kallsyms_lookup_size_offset(start, &size, &offset) ||
+ size == 0) {
+ err = -ENOENT;
+ break;
+ }
+ err = __kprobe_blacklist_add(start, start + size);
+ start += size;
+ }
+ mutex_unlock(&kprobe_blacklist_mutex);
+ return err;
+}
+
/*
* Lookup and populate the kprobe_blacklist.
*
@@ -2043,8 +2068,8 @@ NOKPROBE_SYMBOL(dump_kprobe);
static int populate_kprobe_blacklist(unsigned long *start, unsigned long *end)
{
unsigned long *iter;
- struct kprobe_blacklist_entry *ent;
unsigned long offset = 0, size = 0;
+ int ret;

mutex_lock(&kprobe_blacklist_mutex);
for (iter = start; iter < end; iter++) {
@@ -2052,14 +2077,7 @@ static int populate_kprobe_blacklist(unsigned long *start, unsigned long *end)
pr_err("Failed to find blacklist %p\n", (void *)*iter);
continue;
}
-
- ent = kmalloc(sizeof(*ent), GFP_KERNEL);
- if (!ent)
- return -ENOMEM;
- ent->start_addr = *iter;
- ent->end_addr = *iter + size;
- INIT_LIST_HEAD(&ent->list);
- list_add_tail(&ent->list, &kprobe_blacklist);
+ ret = __kprobe_blacklist_add(*iter, *iter + size);
}
mutex_unlock(&kprobe_blacklist_mutex);

@@ -2154,7 +2172,15 @@ static int __init init_kprobes(void)

err = populate_kprobe_blacklist(__start_kprobe_blacklist,
__stop_kprobe_blacklist);
- if (err) {
+
+ if (err >= 0 && __kprobes_text_start != __kprobes_text_end) {
+ /* The __kprobes marked functions must not be probed */
+ err = kprobe_blacklist_add_range(
+ (unsigned long)__kprobes_text_start,
+ (unsigned long)__kprobes_text_end);
+ }
+
+ if (err < 0) {
pr_err("kprobes: failed to populate blacklist: %d\n", err);
pr_err("Please take care of using kprobes.\n");
}



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