[PATCH 25/51] sctp: pass a kernel pointer to sctp_setsockopt_hmac_ident

[Christoph Hellwig]

Use the kernel pointer that sctp_setsockopt has available instead of
directly handling the user pointer.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 net/sctp/socket.c | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index f68aa3936df3f3..a573af7dfe41f5 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3565,13 +3565,11 @@ static int sctp_setsockopt_auth_chunk(struct sock *sk,
  * endpoint requires the peer to use.
  */
 static int sctp_setsockopt_hmac_ident(struct sock *sk,
-                                     char __user *optval,
+                                     struct sctp_hmacalgo *hmacs,
                                      unsigned int optlen)
 {
        struct sctp_endpoint *ep = sctp_sk(sk)->ep;
-       struct sctp_hmacalgo *hmacs;
        u32 idents;
-       int err;
 
        if (!ep->auth_enable)
                return -EACCES;
@@ -3581,21 +3579,12 @@ static int sctp_setsockopt_hmac_ident(struct sock *sk,
        optlen = min_t(unsigned int, optlen, sizeof(struct sctp_hmacalgo) +
                                             SCTP_AUTH_NUM_HMACS * sizeof(u16));
 
-       hmacs = memdup_user(optval, optlen);
-       if (IS_ERR(hmacs))
-               return PTR_ERR(hmacs);
-
        idents = hmacs->shmac_num_idents;
        if (idents == 0 || idents > SCTP_AUTH_NUM_HMACS ||
-           (idents * sizeof(u16)) > (optlen - sizeof(struct sctp_hmacalgo))) {
-               err = -EINVAL;
-               goto out;
-       }
+           (idents * sizeof(u16)) > (optlen - sizeof(struct sctp_hmacalgo)))
+               return -EINVAL;
 
-       err = sctp_auth_ep_set_hmacs(ep, hmacs);
-out:
-       kfree(hmacs);
-       return err;
+       return sctp_auth_ep_set_hmacs(ep, hmacs);
 }
 
 /*
@@ -4699,7 +4688,7 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
                retval = sctp_setsockopt_auth_chunk(sk, kopt, optlen);
                break;
        case SCTP_HMAC_IDENT:
-               retval = sctp_setsockopt_hmac_ident(sk, optval, optlen);
+               retval = sctp_setsockopt_hmac_ident(sk, kopt, optlen);
                break;
        case SCTP_AUTH_KEY:
                retval = sctp_setsockopt_auth_key(sk, optval, optlen);
-- 
2.27.0