crypto: algif_skcipher - Load TX SG list after waiting

commit 4f0414e54e4d1893c6f08260693f8ef84c929293 upstream.

We need to load the TX SG list in sendmsg(2) after waiting for
incoming data, not before.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 83187f497c7c65dddd2248170a50976e568d82e5..bb68c92e68c6544a5b14047be5b79511c56055e1 100644 (file)
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -441,13 +441,6 @@ static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
                char __user *from = iov->iov_base;
 
                while (seglen) {
-                       sgl = list_first_entry(&ctx->tsgl,
-                                              struct skcipher_sg_list, list);
-                       sg = sgl->sg;
-
-                       while (!sg->length)
-                               sg++;
-
                        used = ctx->used;
                        if (!used) {
                                err = skcipher_wait_for_data(sk, flags);
@@ -469,6 +462,13 @@ static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
                        if (!used)
                                goto free;
 
+                       sgl = list_first_entry(&ctx->tsgl,
+                                              struct skcipher_sg_list, list);
+                       sg = sgl->sg;
+
+                       while (!sg->length)
+                               sg++;
+
                        ablkcipher_request_set_crypt(&ctx->req, sg,
                                                     ctx->rsgl.sg, used,
                                                     ctx->iv);