[PATCH 2/5] kprobes: verify jprobe entry point

[Namhyung Kim <namhyung@gmail.com>]

verify jprobe's entry point is a function entry point
using kallsyms' offset value.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 kernel/kprobes.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8f96701..1b0dbe0 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1339,14 +1339,18 @@ int __kprobes register_jprobes(struct jprobe **jps, int num)
 	if (num <= 0)
 		return -EINVAL;
 	for (i = 0; i < num; i++) {
-		unsigned long addr;
+		unsigned long addr, offset;
 		jp = jps[i];
 		addr = arch_deref_entry_point(jp->entry);
 
-		/* Todo: Verify probepoint is a function entry point */
-		jp->kp.pre_handler = setjmp_pre_handler;
-		jp->kp.break_handler = longjmp_break_handler;
-		ret = register_kprobe(&jp->kp);
+		/* Verify probepoint is a function entry point */
+		if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
+		    offset == 0) {
+			jp->kp.pre_handler = setjmp_pre_handler;
+			jp->kp.break_handler = longjmp_break_handler;
+			ret = register_kprobe(&jp->kp);
+		} else
+			ret = -EINVAL;
 
 		if (ret < 0) {
 			if (i > 0)
-- 
1.7.2.2