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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	dmaengine@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] dmaengine: dw-edma: Fix use after free in dw_edma_alloc_chunk()
Date: Mon, 14 Dec 2020 14:56:52 +0300	[thread overview]
Message-ID: <X9dTBFrUPEvvW7qc@mwanda> (raw)

If the dw_edma_alloc_burst() function fails then we free "chunk" but
it's still on the "desc->chunk->list" list so it will lead to a use
after free.  Also the "->chunks_alloc" count is incremented when it
shouldn't be.

In current kernels small allocations are guaranteed to succeed and
dw_edma_alloc_burst() can't fail so this will not actually affect
runtime.

Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Based on static analysis.  Not tested.

 drivers/dma/dw-edma/dw-edma-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index b971505b8715..08d71dafa001 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -86,12 +86,12 @@ static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc)
 
 	if (desc->chunk) {
 		/* Create and add new element into the linked list */
-		desc->chunks_alloc++;
-		list_add_tail(&chunk->list, &desc->chunk->list);
 		if (!dw_edma_alloc_burst(chunk)) {
 			kfree(chunk);
 			return NULL;
 		}
+		desc->chunks_alloc++;
+		list_add_tail(&chunk->list, &desc->chunk->list);
 	} else {
 		/* List head */
 		chunk->burst = NULL;
-- 
2.29.2


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Vinod Koul <vkoul@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	dmaengine@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] dmaengine: dw-edma: Fix use after free in dw_edma_alloc_chunk()
Date: Mon, 14 Dec 2020 11:56:52 +0000	[thread overview]
Message-ID: <X9dTBFrUPEvvW7qc@mwanda> (raw)

If the dw_edma_alloc_burst() function fails then we free "chunk" but
it's still on the "desc->chunk->list" list so it will lead to a use
after free.  Also the "->chunks_alloc" count is incremented when it
shouldn't be.

In current kernels small allocations are guaranteed to succeed and
dw_edma_alloc_burst() can't fail so this will not actually affect
runtime.

Fixes: e63d79d1ffcd ("dmaengine: Add Synopsys eDMA IP core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Based on static analysis.  Not tested.

 drivers/dma/dw-edma/dw-edma-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index b971505b8715..08d71dafa001 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -86,12 +86,12 @@ static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc)
 
 	if (desc->chunk) {
 		/* Create and add new element into the linked list */
-		desc->chunks_alloc++;
-		list_add_tail(&chunk->list, &desc->chunk->list);
 		if (!dw_edma_alloc_burst(chunk)) {
 			kfree(chunk);
 			return NULL;
 		}
+		desc->chunks_alloc++;
+		list_add_tail(&chunk->list, &desc->chunk->list);
 	} else {
 		/* List head */
 		chunk->burst = NULL;
-- 
2.29.2

             reply	other threads:[~2020-12-14 12:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-14 11:56 Dan Carpenter [this message]
2020-12-14 11:56 ` [PATCH] dmaengine: dw-edma: Fix use after free in dw_edma_alloc_chunk() Dan Carpenter
2020-12-16 17:13 ` Gustavo Pimentel
2020-12-21 16:22 ` Vinod Koul
2020-12-21 16:34   ` Vinod Koul

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