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dmaengine: pxa_dma: Prefer struct_size over open coded arithmetic

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As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, use the struct_size() helper to do the arithmetic instead of the
argument "size + count * size" in the kzalloc() function.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Signed-off-by: Len Baker <len.baker@gmx.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
This commit is contained in:
Len Baker 2021-09-18 12:40:55 +02:00 committed by Gustavo A. R. Silva
parent 5dfbbb668a
commit 50740d5de6
1 changed files with 1 additions and 2 deletions
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3
drivers/dma/pxa_dma.c
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@ -742,8 +742,7 @@ pxad_alloc_desc(struct pxad_chan *chan, unsigned int nb_hw_desc)
dma_addr_t dma;
int i;
sw_desc = kzalloc(sizeof(*sw_desc) +
nb_hw_desc * sizeof(struct pxad_desc_hw *),
sw_desc = kzalloc(struct_size(sw_desc, hw_desc, nb_hw_desc),
GFP_NOWAIT);
if (!sw_desc)
return NULL;