[PATCH] spi: Fix possible ZERO_SIZE_PTR pointer dereferencing error.

[PATCH] spi: Fix possible ZERO_SIZE_PTR pointer dereferencing error.

[Xiubo Li]

Since we cannot make sure the 'n' will always be none zero here, and
then if either equal to zero, the kzalloc() will return ZERO_SIZE_PTR,
which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling
kzalloc().

Signed-off-by: Xiubo Li <Li.Xiubo-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
---
 drivers/spi/spi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 95cfe3b..e19512f 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -552,6 +552,9 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 	struct boardinfo *bi;
 	int i;
 
+	if (!n)
+		return -EINVAL;
+
 	bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 	if (!bi)
 		return -ENOMEM;
-- 
2.1.0.27.g96db324

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Re: [PATCH] spi: Fix possible ZERO_SIZE_PTR pointer dereferencing error.

[Mark Brown]

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On Wed, Sep 24, 2014 at 02:30:29PM +0800, Xiubo Li wrote:
> Since we cannot make sure the 'n' will always be none zero here, and
> then if either equal to zero, the kzalloc() will return ZERO_SIZE_PTR,
> which equals to ((void *)16).

Applied, thanks.

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