kprobes: Verify jprobe entry point

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>
LKML-Reference: <1284512670-2369-3-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 5 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 8f967016cef0..1b0dbe067077 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)