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-rw-r--r--crypto/ahash.c147
1 files changed, 94 insertions, 53 deletions
diff --git a/crypto/ahash.c b/crypto/ahash.c
index a92dc382f781..6e7223392e80 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -190,6 +190,75 @@ static inline unsigned int ahash_align_buffer_size(unsigned len,
return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
}
+static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
+{
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ unsigned long alignmask = crypto_ahash_alignmask(tfm);
+ unsigned int ds = crypto_ahash_digestsize(tfm);
+ struct ahash_request_priv *priv;
+
+ priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
+ (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
+ GFP_KERNEL : GFP_ATOMIC);
+ if (!priv)
+ return -ENOMEM;
+
+ /*
+ * WARNING: Voodoo programming below!
+ *
+ * The code below is obscure and hard to understand, thus explanation
+ * is necessary. See include/crypto/hash.h and include/linux/crypto.h
+ * to understand the layout of structures used here!
+ *
+ * The code here will replace portions of the ORIGINAL request with
+ * pointers to new code and buffers so the hashing operation can store
+ * the result in aligned buffer. We will call the modified request
+ * an ADJUSTED request.
+ *
+ * The newly mangled request will look as such:
+ *
+ * req {
+ * .result = ADJUSTED[new aligned buffer]
+ * .base.complete = ADJUSTED[pointer to completion function]
+ * .base.data = ADJUSTED[*req (pointer to self)]
+ * .priv = ADJUSTED[new priv] {
+ * .result = ORIGINAL(result)
+ * .complete = ORIGINAL(base.complete)
+ * .data = ORIGINAL(base.data)
+ * }
+ */
+
+ priv->result = req->result;
+ priv->complete = req->base.complete;
+ priv->data = req->base.data;
+ /*
+ * WARNING: We do not backup req->priv here! The req->priv
+ * is for internal use of the Crypto API and the
+ * user must _NOT_ _EVER_ depend on it's content!
+ */
+
+ req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
+ req->base.complete = cplt;
+ req->base.data = req;
+ req->priv = priv;
+
+ return 0;
+}
+
+static void ahash_restore_req(struct ahash_request *req)
+{
+ struct ahash_request_priv *priv = req->priv;
+
+ /* Restore the original crypto request. */
+ req->result = priv->result;
+ req->base.complete = priv->complete;
+ req->base.data = priv->data;
+ req->priv = NULL;
+
+ /* Free the req->priv.priv from the ADJUSTED request. */
+ kzfree(priv);
+}
+
static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
{
struct ahash_request_priv *priv = req->priv;
@@ -201,47 +270,37 @@ static void ahash_op_unaligned_finish(struct ahash_request *req, int err)
memcpy(priv->result, req->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
- kzfree(priv);
+ ahash_restore_req(req);
}
static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
- struct ahash_request_priv *priv = areq->priv;
- crypto_completion_t complete = priv->complete;
- void *data = priv->data;
- ahash_op_unaligned_finish(areq, err);
+ /*
+ * Restore the original request, see ahash_op_unaligned() for what
+ * goes where.
+ *
+ * The "struct ahash_request *req" here is in fact the "req.base"
+ * from the ADJUSTED request from ahash_op_unaligned(), thus as it
+ * is a pointer to self, it is also the ADJUSTED "req" .
+ */
- areq->base.complete = complete;
- areq->base.data = data;
+ /* First copy req->result into req->priv.result */
+ ahash_op_unaligned_finish(areq, err);
- complete(&areq->base, err);
+ /* Complete the ORIGINAL request. */
+ areq->base.complete(&areq->base, err);
}
static int ahash_op_unaligned(struct ahash_request *req,
int (*op)(struct ahash_request *))
{
- struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
- unsigned long alignmask = crypto_ahash_alignmask(tfm);
- unsigned int ds = crypto_ahash_digestsize(tfm);
- struct ahash_request_priv *priv;
int err;
- priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
- (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
- GFP_KERNEL : GFP_ATOMIC);
- if (!priv)
- return -ENOMEM;
-
- priv->result = req->result;
- priv->complete = req->base.complete;
- priv->data = req->base.data;
-
- req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
- req->base.complete = ahash_op_unaligned_done;
- req->base.data = req;
- req->priv = priv;
+ err = ahash_save_req(req, ahash_op_unaligned_done);
+ if (err)
+ return err;
err = op(req);
ahash_op_unaligned_finish(req, err);
@@ -290,19 +349,16 @@ static void ahash_def_finup_finish2(struct ahash_request *req, int err)
memcpy(priv->result, req->result,
crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));
- kzfree(priv);
+ ahash_restore_req(req);
}
static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
- struct ahash_request_priv *priv = areq->priv;
- crypto_completion_t complete = priv->complete;
- void *data = priv->data;
ahash_def_finup_finish2(areq, err);
- complete(data, err);
+ areq->base.complete(&areq->base, err);
}
static int ahash_def_finup_finish1(struct ahash_request *req, int err)
@@ -322,38 +378,23 @@ out:
static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
{
struct ahash_request *areq = req->data;
- struct ahash_request_priv *priv = areq->priv;
- crypto_completion_t complete = priv->complete;
- void *data = priv->data;
err = ahash_def_finup_finish1(areq, err);
- complete(data, err);
+ areq->base.complete(&areq->base, err);
}
static int ahash_def_finup(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
- unsigned long alignmask = crypto_ahash_alignmask(tfm);
- unsigned int ds = crypto_ahash_digestsize(tfm);
- struct ahash_request_priv *priv;
-
- priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
- (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
- GFP_KERNEL : GFP_ATOMIC);
- if (!priv)
- return -ENOMEM;
-
- priv->result = req->result;
- priv->complete = req->base.complete;
- priv->data = req->base.data;
+ int err;
- req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
- req->base.complete = ahash_def_finup_done1;
- req->base.data = req;
- req->priv = priv;
+ err = ahash_save_req(req, ahash_def_finup_done1);
+ if (err)
+ return err;
- return ahash_def_finup_finish1(req, tfm->update(req));
+ err = tfm->update(req);
+ return ahash_def_finup_finish1(req, err);
}
static int ahash_no_export(struct ahash_request *req, void *out)
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-11 07:51:10 +0000