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dmaengine: mcf-edma: Fix a potential un-allocated memory access

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When 'mcf_edma' is allocated, some space is allocated for a
flexible array at the end of the struct. 'chans' item are allocated, that is
to say 'pdata->dma_channels'.

Then, this number of item is stored in 'mcf_edma->n_chans'.

A few lines later, if 'mcf_edma->n_chans' is 0, then a default value of 64
is set.

This ends to no space allocated by devm_kzalloc() because chans was 0, but
64 items are read and/or written in some not allocated memory.

Change the logic to define a default value before allocating the memory.

Fixes: e7a3ff92ea ("dmaengine: fsl-edma: add ColdFire mcf5441x edma support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/f55d914407c900828f6fad3ea5fa791a5f17b9a4.1685172449.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Christophe JAILLET 2023-07-12 18:26:45 +05:30 committed by Vinod Koul
parent a68b48afc0
commit 0a46781c89
1 changed files with 7 additions and 6 deletions
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13
drivers/dma/mcf-edma.c
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@ -190,7 +190,13 @@ static int mcf_edma_probe(struct platform_device *pdev)
return -EINVAL;
}
chans = pdata->dma_channels;
if (!pdata->dma_channels) {
dev_info(&pdev->dev, "setting default channel number to 64");
chans = 64;
} else {
chans = pdata->dma_channels;
}
len = sizeof(*mcf_edma) + sizeof(*mcf_chan) * chans;
mcf_edma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
if (!mcf_edma)
@ -202,11 +208,6 @@ static int mcf_edma_probe(struct platform_device *pdev)
mcf_edma->drvdata = &mcf_data;
mcf_edma->big_endian = 1;
if (!mcf_edma->n_chans) {
dev_info(&pdev->dev, "setting default channel number to 64");
mcf_edma->n_chans = 64;
}
mutex_init(&mcf_edma->fsl_edma_mutex);
mcf_edma->membase = devm_platform_ioremap_resource(pdev, 0);