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dmaengine: dw-edma: Fix use after free in dw_edma_alloc_chunk()

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commit 595a334148449bd1d27cf5d6fcb3b0d718cb1b9f upstream.

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>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Link: https://lore.kernel.org/r/X9dTBFrUPEvvW7qc@mwanda
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dan Carpenter 2020-12-14 14:56:52 +03:00 committed by Greg Kroah-Hartman
parent f6dd8c259a
commit b77e0283ef
1 changed files with 2 additions and 2 deletions
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4
drivers/dma/dw-edma/dw-edma-core.c
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@ -85,12 +85,12 @@ 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;