[PATCH] Fix memory overwriting issue when copy an address to user space

[lebon zhou]

When application provided buffer size less than sockaddr_storage, then
kernel will overwrite some memory area which may cause memory corruption,
e.g.: in recvmsg case, let msg_name=malloc(8) and msg_namelen=8, then
usually application can call recvmsg successful but actually application
memory get corrupted.

Fix to return EINVAL when application buffer size less than
sockaddr_storage.

Signed-off-by: lebon.zhou <lebon.zhou@xxxxxxxxx>
---
 net/socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/socket.c b/net/socket.c
index 976426d03f09..dc32b1b899df 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -229,7 +229,7 @@ static int move_addr_to_user(struct
sockaddr_storage *kaddr, int klen,
         return err;
     if (len > klen)
         len = klen;
-    if (len < 0)
+    if (len < 0 || len < klen)
         return -EINVAL;
     if (len) {
         if (audit_sockaddr(klen, kaddr))
--
2.22.0