[PATCH 26/49] sctp: pass a kernel pointer to sctp_setsockopt_auth_key

[Christoph Hellwig]

Use the kernel pointer that sctp_setsockopt has available instead of
directly handling the user pointer.  Adapt sctp_setsockopt to use a
kzfree for this case.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 net/sctp/socket.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 88edf5413fd22..d3442dcd49aa8 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3591,11 +3591,10 @@ static int sctp_setsockopt_hmac_ident(struct sock *sk,
  * association shared key.
  */
 static int sctp_setsockopt_auth_key(struct sock *sk,
-                                   char __user *optval,
+                                   struct sctp_authkey *authkey,
                                    unsigned int optlen)
 {
        struct sctp_endpoint *ep = sctp_sk(sk)->ep;
-       struct sctp_authkey *authkey;
        struct sctp_association *asoc;
        int ret = -EINVAL;
 
@@ -3606,10 +3605,6 @@ static int sctp_setsockopt_auth_key(struct sock *sk,
         */
        optlen = min_t(unsigned int, optlen, USHRT_MAX + sizeof(*authkey));
 
-       authkey = memdup_user(optval, optlen);
-       if (IS_ERR(authkey))
-               return PTR_ERR(authkey);
-
        if (authkey->sca_keylength > optlen - sizeof(*authkey))
                goto out;
 
@@ -3646,7 +3641,6 @@ static int sctp_setsockopt_auth_key(struct sock *sk,
        }
 
 out:
-       kzfree(authkey);
        return ret;
 }
 
@@ -4688,7 +4682,7 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
                retval = sctp_setsockopt_hmac_ident(sk, kopt, optlen);
                break;
        case SCTP_AUTH_KEY:
-               retval = sctp_setsockopt_auth_key(sk, optval, optlen);
+               retval = sctp_setsockopt_auth_key(sk, kopt, optlen);
                break;
        case SCTP_AUTH_ACTIVE_KEY:
                retval = sctp_setsockopt_active_key(sk, optval, optlen);
@@ -4771,7 +4765,10 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        }
 
        release_sock(sk);
-       kfree(kopt);
+       if (optname == SCTP_AUTH_KEY)
+               kzfree(kopt);
+       else
+               kfree(kopt);
 
 out_nounlock:
        return retval;
-- 
2.26.2