[PATCH 01/49] sctp: copy the optval from user space in sctp_setsockopt

[Christoph Hellwig]

Prepare for for moving the copy_from_user from the individual sockopts
to the main setsockopt helper.  As of this commit the kopt variable
is not used yet, but the following commits will start using it.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 net/sctp/socket.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 827a9903ee288..ee6a618ee3e8e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4670,6 +4670,7 @@ static int sctp_setsockopt_pf_expose(struct sock *sk,
 static int sctp_setsockopt(struct sock *sk, int level, int optname,
                           char __user *optval, unsigned int optlen)
 {
+       void *kopt = NULL;
        int retval = 0;
 
        pr_debug("%s: sk:%p, optname:%d\n", __func__, sk, optname);
@@ -4686,6 +4687,12 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
                goto out_nounlock;
        }
 
+       if (optlen > 0) {
+               kopt = memdup_user(optval, optlen);
+               if (IS_ERR(kopt))
+                       return PTR_ERR(kopt);
+       }
+
        lock_sock(sk);
 
        switch (optname) {
@@ -4871,6 +4878,7 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        }
 
        release_sock(sk);
+       kfree(kopt);
 
 out_nounlock:
        return retval;
-- 
2.26.2