crypto: atmel-sha - fix race in atmel_sha_final()

When (!ctx->bufcnt && !(ctx->flags & SHA_FLAGS_PAD)), the former source
code used to set the SHA_FLAGS_BUSY without checking whether this flag was
already set. If so, the hardware is already processing another hash
request so the processing of the req argument of atmel_sha_final() should
be delayed by queueing this request, the same way as done for the
(ctx->bufcnt != 0) case.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 22 deletions

diff --git a/drivers/crypto/atmel-sha.c b/drivers/crypto/atmel-sha.c
index e4757f8957ae..7b93586154a7 100644
--- a/drivers/crypto/atmel-sha.c
+++ b/drivers/crypto/atmel-sha.c
@@ -979,37 +979,17 @@ static int atmel_sha_update(struct ahash_request *req)
 static int atmel_sha_final(struct ahash_request *req)
 {
         struct atmel_sha_reqctx *ctx = ahash_request_ctx(req);
-        struct atmel_sha_ctx *tctx = crypto_tfm_ctx(req->base.tfm);
-        struct atmel_sha_dev *dd = tctx->dd;
-
-        int err = 0;
 
         ctx->flags |= SHA_FLAGS_FINUP;
 
         if (ctx->flags & SHA_FLAGS_ERROR)
                 return 0; /* uncompleted hash is not needed */
 
-        if (ctx->bufcnt) {
-                return atmel_sha_enqueue(req, SHA_OP_FINAL);
-        } else if (!(ctx->flags & SHA_FLAGS_PAD)) { /* add padding */
-                err = atmel_sha_hw_init(dd);
-                if (err)
-                        goto err1;
-
-                dd->req = req;
-                dd->flags |= SHA_FLAGS_BUSY;
-                err = atmel_sha_final_req(dd);
-        } else {
+        if (ctx->flags & SHA_FLAGS_PAD)
                 /* copy ready hash (+ finalize hmac) */
                 return atmel_sha_finish(req);
-        }
-
-err1:
-        if (err != -EINPROGRESS)
-                /* done_task will not finish it, so do it here */
-                atmel_sha_finish_req(req, err);
 
-        return err;
+        return atmel_sha_enqueue(req, SHA_OP_FINAL);
 }
 
 static int atmel_sha_finup(struct ahash_request *req)