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WTF: patch "[PATCH] crypto: qat - remove dma_free_coherent() for RSA" was seriously submitted to be applied to the 5.18-stable tree?

PATCH [email protected] 1 participant 1 message Jun 6, 2022

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The patch below was submitted to be applied to the 5.18-stable tree.

I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.

I could be totally wrong, and if so, please respond to <[email protected]> and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 3dfaf0071ed74d7a9c6b3c9ea4df7a6f8e423c2a Mon Sep 17 00:00:00 2001
From: Giovanni Cabiddu <[email protected]>
Date: Mon, 9 May 2022 14:34:12 +0100
Subject: [PATCH] crypto: qat - remove dma_free_coherent() for RSA

After commit f5ff79fddf0e ("dma-mapping: remove CONFIG_DMA_REMAP"), if the algorithms are enabled, the driver crashes with a BUG_ON while executing vunmap() in the context of a tasklet. This is due to the fact that the function dma_free_coherent() cannot be called in an interrupt context (see Documentation/core-api/dma-api-howto.rst).

The functions qat_rsa_enc() and qat_rsa_dec() allocate memory with dma_alloc_coherent() if the source or the destination buffers are made of multiple flat buffers or of a size that is not compatible with the hardware.
This memory is then freed with dma_free_coherent() in the context of a tasklet invoked to handle the response for the corresponding request.

Replace allocations with dma_alloc_coherent() in the functions qat_rsa_enc() and qat_rsa_dec() with kmalloc() + dma_map_single().

Cc [email protected]
Fixes a990532023b9 ("crypto: qat - Add support for RSA algorithm")
Signed-off-by Giovanni Cabiddu <[email protected]>
Reviewed-by Adam Guerin <[email protected]>
Reviewed-by Wojciech Ziemba <[email protected]>
Signed-off-by Herbert Xu <[email protected]>
drivers/crypto/qat/qat_common/qat_asym_algs.c +60 -77
index 2bc02c75398e..b31372bddb96 100644
@@ -529,25 +529,22 @@ static void qat_rsa_cb(struct icp_qat_fw_pke_resp *resp)
 
 	err = (err == ICP_QAT_FW_COMN_STATUS_FLAG_OK) ? 0 : -EINVAL;
 
-	if (req->src_align)
-		dma_free_coherent(dev, req->ctx.rsa->key_sz, req->src_align,
-				  req->in.rsa.enc.m);
-	else
-		dma_unmap_single(dev, req->in.rsa.enc.m, req->ctx.rsa->key_sz,
-				 DMA_TO_DEVICE);
+	kfree_sensitive(req->src_align);
+
+	dma_unmap_single(dev, req->in.rsa.enc.m, req->ctx.rsa->key_sz,
+			 DMA_TO_DEVICE);
 
 	areq->dst_len = req->ctx.rsa->key_sz;
 	if (req->dst_align) {
 		scatterwalk_map_and_copy(req->dst_align, areq->dst, 0,
 					 areq->dst_len, 1);
 
-		dma_free_coherent(dev, req->ctx.rsa->key_sz, req->dst_align,
-				  req->out.rsa.enc.c);
-	} else {
-		dma_unmap_single(dev, req->out.rsa.enc.c, req->ctx.rsa->key_sz,
-				 DMA_FROM_DEVICE);
+		kfree_sensitive(req->dst_align);
 	}
 
+	dma_unmap_single(dev, req->out.rsa.enc.c, req->ctx.rsa->key_sz,
+			 DMA_FROM_DEVICE);
+
 	dma_unmap_single(dev, req->phy_in, sizeof(struct qat_rsa_input_params),
 			 DMA_TO_DEVICE);
 	dma_unmap_single(dev, req->phy_out,

@@ -664,6 +661,7 @@ static int qat_rsa_enc(struct akcipher_request *req)
 	struct qat_asym_request *qat_req =
 			PTR_ALIGN(akcipher_request_ctx(req), 64);
 	struct icp_qat_fw_pke_request *msg = &qat_req->req;
+	u8 *vaddr;
 	int ret;
 
 	if (unlikely(!ctx->n || !ctx->e))

@@ -701,40 +699,39 @@ static int qat_rsa_enc(struct akcipher_request *req)
 	 */
 	if (sg_is_last(req->src) && req->src_len == ctx->key_sz) {
 		qat_req->src_align = NULL;
-		qat_req->in.rsa.enc.m = dma_map_single(dev, sg_virt(req->src),
-						   req->src_len, DMA_TO_DEVICE);
-		if (unlikely(dma_mapping_error(dev, qat_req->in.rsa.enc.m)))
-			return ret;
-
+		vaddr = sg_virt(req->src);
 	} else {
 		int shift = ctx->key_sz - req->src_len;
 
-		qat_req->src_align = dma_alloc_coherent(dev, ctx->key_sz,
-							&qat_req->in.rsa.enc.m,
-							GFP_KERNEL);
+		qat_req->src_align = kzalloc(ctx->key_sz, GFP_KERNEL);
 		if (unlikely(!qat_req->src_align))
 			return ret;
 
 		scatterwalk_map_and_copy(qat_req->src_align + shift, req->src,
 					 0, req->src_len, 0);
+		vaddr = qat_req->src_align;
 	}
-	if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) {
-		qat_req->dst_align = NULL;
-		qat_req->out.rsa.enc.c = dma_map_single(dev, sg_virt(req->dst),
-							req->dst_len,
-							DMA_FROM_DEVICE);
 
-		if (unlikely(dma_mapping_error(dev, qat_req->out.rsa.enc.c)))
-			goto unmap_src;
+	qat_req->in.rsa.enc.m = dma_map_single(dev, vaddr, ctx->key_sz,
+					       DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(dev, qat_req->in.rsa.enc.m)))
+		goto unmap_src;
 
+	if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) {
+		qat_req->dst_align = NULL;
+		vaddr = sg_virt(req->dst);
 	} else {
-		qat_req->dst_align = dma_alloc_coherent(dev, ctx->key_sz,
-							&qat_req->out.rsa.enc.c,
-							GFP_KERNEL);
+		qat_req->dst_align = kzalloc(ctx->key_sz, GFP_KERNEL);
 		if (unlikely(!qat_req->dst_align))
 			goto unmap_src;
-
+		vaddr = qat_req->dst_align;
 	}
+
+	qat_req->out.rsa.enc.c = dma_map_single(dev, vaddr, ctx->key_sz,
+						DMA_FROM_DEVICE);
+	if (unlikely(dma_mapping_error(dev, qat_req->out.rsa.enc.c)))
+		goto unmap_dst;
+
 	qat_req->in.rsa.in_tab[3] = 0;
 	qat_req->out.rsa.out_tab[1] = 0;
 	qat_req->phy_in = dma_map_single(dev, &qat_req->in.rsa.enc.m,

@@ -772,21 +769,15 @@ static int qat_rsa_enc(struct akcipher_request *req)
 				 sizeof(struct qat_rsa_input_params),
 				 DMA_TO_DEVICE);
 unmap_dst:
-	if (qat_req->dst_align)
-		dma_free_coherent(dev, ctx->key_sz, qat_req->dst_align,
-				  qat_req->out.rsa.enc.c);
-	else
-		if (!dma_mapping_error(dev, qat_req->out.rsa.enc.c))
-			dma_unmap_single(dev, qat_req->out.rsa.enc.c,
-					 ctx->key_sz, DMA_FROM_DEVICE);
+	if (!dma_mapping_error(dev, qat_req->out.rsa.enc.c))
+		dma_unmap_single(dev, qat_req->out.rsa.enc.c,
+				 ctx->key_sz, DMA_FROM_DEVICE);
+	kfree_sensitive(qat_req->dst_align);
 unmap_src:
-	if (qat_req->src_align)
-		dma_free_coherent(dev, ctx->key_sz, qat_req->src_align,
-				  qat_req->in.rsa.enc.m);
-	else
-		if (!dma_mapping_error(dev, qat_req->in.rsa.enc.m))
-			dma_unmap_single(dev, qat_req->in.rsa.enc.m,
-					 ctx->key_sz, DMA_TO_DEVICE);
+	if (!dma_mapping_error(dev, qat_req->in.rsa.enc.m))
+		dma_unmap_single(dev, qat_req->in.rsa.enc.m, ctx->key_sz,
+				 DMA_TO_DEVICE);
+	kfree_sensitive(qat_req->src_align);
 	return ret;
 }
 

@@ -799,6 +790,7 @@ static int qat_rsa_dec(struct akcipher_request *req)
 	struct qat_asym_request *qat_req =
 			PTR_ALIGN(akcipher_request_ctx(req), 64);
 	struct icp_qat_fw_pke_request *msg = &qat_req->req;
+	u8 *vaddr;
 	int ret;
 
 	if (unlikely(!ctx->n || !ctx->d))

@@ -846,40 +838,37 @@ static int qat_rsa_dec(struct akcipher_request *req)
 	 */
 	if (sg_is_last(req->src) && req->src_len == ctx->key_sz) {
 		qat_req->src_align = NULL;
-		qat_req->in.rsa.dec.c = dma_map_single(dev, sg_virt(req->src),
-						   req->dst_len, DMA_TO_DEVICE);
-		if (unlikely(dma_mapping_error(dev, qat_req->in.rsa.dec.c)))
-			return ret;
-
+		vaddr = sg_virt(req->src);
 	} else {
 		int shift = ctx->key_sz - req->src_len;
 
-		qat_req->src_align = dma_alloc_coherent(dev, ctx->key_sz,
-							&qat_req->in.rsa.dec.c,
-							GFP_KERNEL);
+		qat_req->src_align = kzalloc(ctx->key_sz, GFP_KERNEL);
 		if (unlikely(!qat_req->src_align))
 			return ret;
 
 		scatterwalk_map_and_copy(qat_req->src_align + shift, req->src,
 					 0, req->src_len, 0);
+		vaddr = qat_req->src_align;
 	}
-	if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) {
-		qat_req->dst_align = NULL;
-		qat_req->out.rsa.dec.m = dma_map_single(dev, sg_virt(req->dst),
-						    req->dst_len,
-						    DMA_FROM_DEVICE);
 
-		if (unlikely(dma_mapping_error(dev, qat_req->out.rsa.dec.m)))
-			goto unmap_src;
+	qat_req->in.rsa.dec.c = dma_map_single(dev, vaddr, ctx->key_sz,
+					       DMA_TO_DEVICE);
+	if (unlikely(dma_mapping_error(dev, qat_req->in.rsa.dec.c)))
+		goto unmap_src;
 
+	if (sg_is_last(req->dst) && req->dst_len == ctx->key_sz) {
+		qat_req->dst_align = NULL;
+		vaddr = sg_virt(req->dst);
 	} else {
-		qat_req->dst_align = dma_alloc_coherent(dev, ctx->key_sz,
-							&qat_req->out.rsa.dec.m,
-							GFP_KERNEL);
+		qat_req->dst_align = kzalloc(ctx->key_sz, GFP_KERNEL);
 		if (unlikely(!qat_req->dst_align))
 			goto unmap_src;
-
+		vaddr = qat_req->dst_align;
 	}
+	qat_req->out.rsa.dec.m = dma_map_single(dev, vaddr, ctx->key_sz,
+						DMA_FROM_DEVICE);
+	if (unlikely(dma_mapping_error(dev, qat_req->out.rsa.dec.m)))
+		goto unmap_dst;
 
 	if (ctx->crt_mode)
 		qat_req->in.rsa.in_tab[6] = 0;

@@ -925,21 +914,15 @@ static int qat_rsa_dec(struct akcipher_request *req)
 				 sizeof(struct qat_rsa_input_params),
 				 DMA_TO_DEVICE);
 unmap_dst:
-	if (qat_req->dst_align)
-		dma_free_coherent(dev, ctx->key_sz, qat_req->dst_align,
-				  qat_req->out.rsa.dec.m);
-	else
-		if (!dma_mapping_error(dev, qat_req->out.rsa.dec.m))
-			dma_unmap_single(dev, qat_req->out.rsa.dec.m,
-					 ctx->key_sz, DMA_FROM_DEVICE);
+	if (!dma_mapping_error(dev, qat_req->out.rsa.dec.m))
+		dma_unmap_single(dev, qat_req->out.rsa.dec.m,
+				 ctx->key_sz, DMA_FROM_DEVICE);
+	kfree_sensitive(qat_req->dst_align);
 unmap_src:
-	if (qat_req->src_align)
-		dma_free_coherent(dev, ctx->key_sz, qat_req->src_align,
-				  qat_req->in.rsa.dec.c);
-	else
-		if (!dma_mapping_error(dev, qat_req->in.rsa.dec.c))
-			dma_unmap_single(dev, qat_req->in.rsa.dec.c,
-					 ctx->key_sz, DMA_TO_DEVICE);
+	if (!dma_mapping_error(dev, qat_req->in.rsa.dec.c))
+		dma_unmap_single(dev, qat_req->in.rsa.dec.c, ctx->key_sz,
+				 DMA_TO_DEVICE);
+	kfree_sensitive(qat_req->src_align);
 	return ret;
 }