From: Masami Hiramatsu <mhiramat@kernel.org>
To: Ingo Molnar <mingo@redhat.com>, Andrea Righi <righi.andrea@gmail.com>
Cc: "Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
"David S . Miller" <davem@davemloft.net>,
Masami Hiramatsu <mhiramat@kernel.org>,
Yonghong Song <yhs@fb.com>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/3] kprobes: Blacklist symbols in arch-defined prohibited area
Date: Mon, 17 Dec 2018 17:20:55 +0900 [thread overview]
Message-ID: <154503485491.26176.15823229545155174796.stgit@devbox> (raw)
In-Reply-To: <154503482486.26176.6224515860220847638.stgit@devbox>
Blacklist symbols in arch-defined probe-prohibited areas.
With this change, user can see all symbols which are prohibited
to probe in debugfs.
All archtectures which have custom prohibit areas should define
its own arch_populate_kprobe_blacklist() function, but unless that,
all symbols marked __kprobes are blacklisted.
Reported-by: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
Changes in v2:
- Add area based blacklist adding helper function
- Blacklist __kprobes_text symbols by default
- Add __init to default function
---
include/linux/kprobes.h | 3 ++
kernel/kprobes.c | 67 +++++++++++++++++++++++++++++++++++++----------
2 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index e64b26c81c2f..e07e91daaacc 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -242,10 +242,13 @@ 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 arch_populate_kprobe_blacklist(void);
extern bool arch_kprobe_on_func_entry(unsigned long offset);
extern bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
extern bool within_kprobe_blacklist(unsigned long addr);
+extern int kprobe_add_ksym_blacklist(unsigned long entry);
+extern int kprobe_add_area_blacklist(unsigned long start, unsigned long end);
struct kprobe_insn_cache {
struct mutex mutex;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 08e31d863191..f4ddfdd2d07e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2093,6 +2093,47 @@ void dump_kprobe(struct kprobe *kp)
}
NOKPROBE_SYMBOL(dump_kprobe);
+int kprobe_add_ksym_blacklist(unsigned long entry)
+{
+ struct kprobe_blacklist_entry *ent;
+ unsigned long offset = 0, size = 0;
+
+ if (!kernel_text_address(entry) ||
+ !kallsyms_lookup_size_offset(entry, &size, &offset))
+ return -EINVAL;
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+ ent->start_addr = entry;
+ ent->end_addr = entry + size;
+ INIT_LIST_HEAD(&ent->list);
+ list_add_tail(&ent->list, &kprobe_blacklist);
+
+ return (int)size;
+}
+
+/* Add all symbols in given area into kprobe blacklist */
+int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
+{
+ unsigned long entry;
+ int ret = 0;
+
+ for (entry = start; entry < end; entry += ret) {
+ ret = kprobe_add_ksym_blacklist(entry);
+ if (ret < 0)
+ return ret;
+ if (ret == 0) /* In case of alias symbol */
+ ret = 1;
+ }
+ return 0;
+}
+
+int __init __weak arch_populate_kprobe_blacklist(void)
+{
+ return 0;
+}
+
/*
* Lookup and populate the kprobe_blacklist.
*
@@ -2104,26 +2145,24 @@ NOKPROBE_SYMBOL(dump_kprobe);
static int __init populate_kprobe_blacklist(unsigned long *start,
unsigned long *end)
{
+ unsigned long entry;
unsigned long *iter;
- struct kprobe_blacklist_entry *ent;
- unsigned long entry, offset = 0, size = 0;
+ int ret;
for (iter = start; iter < end; iter++) {
entry = arch_deref_entry_point((void *)*iter);
-
- if (!kernel_text_address(entry) ||
- !kallsyms_lookup_size_offset(entry, &size, &offset))
+ ret = kprobe_add_ksym_blacklist(entry);
+ if (ret == -EINVAL)
continue;
-
- ent = kmalloc(sizeof(*ent), GFP_KERNEL);
- if (!ent)
- return -ENOMEM;
- ent->start_addr = entry;
- ent->end_addr = entry + size;
- INIT_LIST_HEAD(&ent->list);
- list_add_tail(&ent->list, &kprobe_blacklist);
+ if (ret < 0)
+ return ret;
}
- return 0;
+
+ /* Symbols in __kprobes_text are blacklisted */
+ ret = kprobe_add_area_blacklist((unsigned long)__kprobes_text_start,
+ (unsigned long)__kprobes_text_end);
+
+ return ret ? : arch_populate_kprobe_blacklist();
}
/* Module notifier call back, checking kprobes on the module */
next prev parent reply other threads:[~2018-12-17 8:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-17 8:20 [PATCH v2 0/3] x86: kprobes: Show correct blaclkist in debugfs Masami Hiramatsu
2018-12-17 8:20 ` Masami Hiramatsu [this message]
2018-12-17 18:18 ` [tip:perf/core] kprobes: Blacklist symbols in arch-defined prohibited area tip-bot for Masami Hiramatsu
2018-12-17 8:21 ` [PATCH v2 2/3] x86/kprobes: Show x86-64 specific blacklisted symbols correctly Masami Hiramatsu
2018-12-17 18:19 ` [tip:perf/core] kprobes/x86: " tip-bot for Masami Hiramatsu
2018-12-17 8:21 ` [PATCH v2 3/3] x86/kprobes: Remove unneeded arch_within_kprobe_blacklist from x86 Masami Hiramatsu
2018-12-17 18:20 ` [tip:perf/core] kprobes/x86: " tip-bot for Masami Hiramatsu
2018-12-17 15:47 ` [PATCH v2 0/3] x86: kprobes: Show correct blaclkist in debugfs Andrea Righi
2018-12-18 4:50 ` Masami Hiramatsu
2018-12-18 17:24 ` Andrea Righi
2018-12-27 17:09 ` Andrea Righi
2019-01-01 13:16 ` Masami Hiramatsu
2019-01-01 13:37 ` Andrea Righi
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