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From: Len Baker <>
To: Daniel Mack <>,
	Haojian Zhuang <>,
	Robert Jarzmik <>,
	Vinod Koul <>
Cc: Len Baker <>,
	"Gustavo A. R. Silva" <>,
	Kees Cook <>,,,,
Subject: [PATCH] dmaengine: pxa_dma: Prefer struct_size over open coded arithmetic
Date: Sat, 18 Sep 2021 12:40:55 +0200	[thread overview]
Message-ID: <> (raw)

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.


Signed-off-by: Len Baker <>
 drivers/dma/pxa_dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index 4a2a796e348c..52d04641e361 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -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),
 	if (!sw_desc)
 		return NULL;

             reply	other threads:[~2021-09-18 10:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-18 10:40 Len Baker [this message]
2021-09-21  0:00 ` Gustavo A. R. Silva
2021-10-20 23:32   ` Gustavo A. R. Silva

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