[PATCH] bpf: use vmemdup_user instead of kvmalloc and copy_from_user

[Yihao Han]

fix memdup_user.cocci warning:
kernel/trace/bpf_trace.c:2450:12-20: WARNING opportunity
for vmemdup_user

Signed-off-by: Yihao Han <hanyihao@xxxxxxxx>
---
 kernel/trace/bpf_trace.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 7fa2ebc07f60..aff2461c1ea2 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2447,13 +2447,9 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 
 	ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
 	if (ucookies) {
-		cookies = kvmalloc(size, GFP_KERNEL);
-		if (!cookies) {
-			err = -ENOMEM;
-			goto error;
-		}
-		if (copy_from_user(cookies, ucookies, size)) {
-			err = -EFAULT;
+		cookies = vmemdup_user(ucookies, size);
+		if (IS_ERR(cookies)) {
+			err = PTR_ERR(cookies);
 			goto error;
 		}
 	}
-- 
2.17.1