From b77e0283efdc2c79d392cf8d7ae9cd5142427199 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Mon, 14 Dec 2020 14:56:52 +0300 Subject: [PATCH] dmaengine: dw-edma: Fix use after free in dw_edma_alloc_chunk() 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 Acked-by: Gustavo Pimentel Link: https://lore.kernel.org/r/X9dTBFrUPEvvW7qc@mwanda Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- 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 7f9a86c3c58f..31577316f80b 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -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;