[PATCH] IB/ocrdma: fix out of bounds access to local buffer

[PATCH] IB/ocrdma: fix out of bounds access to local buffer

[Michael Mera]

In write to debugfs file 'resource_stats' the local buffer 'tmp_str' is
written at index 'count-1' where 'count' is the size of the write, so
potentially 0.

This patch filters odd values for the write size/position to avoid this
type of problem.

Signed-off-by: Michael Mera <dev-5Y08+B5RRAgbhb6IIWwbbQ@public.gmane.org>
---
 drivers/infiniband/hw/ocrdma/ocrdma_stats.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
index f8e4b0a6486f..66056f9a9700 100644
--- a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
+++ b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
@@ -643,7 +643,7 @@ static ssize_t ocrdma_dbgfs_ops_write(struct file *filp,
 	struct ocrdma_stats *pstats = filp->private_data;
 	struct ocrdma_dev *dev = pstats->dev;
 
-	if (count > 32)
+	if (*ppos != 0 || count == 0 || count > sizeof(tmp_str))
 		goto err;
 
 	if (copy_from_user(tmp_str, buffer, count))
-- 
2.9.3

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Re: [PATCH] IB/ocrdma: fix out of bounds access to local buffer

[Leon Romanovsky]

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On Mon, May 01, 2017 at 03:41:16PM +0900, Michael Mera wrote:
> In write to debugfs file 'resource_stats' the local buffer 'tmp_str' is
> written at index 'count-1' where 'count' is the size of the write, so
> potentially 0.
>
> This patch filters odd values for the write size/position to avoid this
> type of problem.
>
> Signed-off-by: Michael Mera <dev-5Y08+B5RRAgbhb6IIWwbbQ@public.gmane.org>
> ---
>  drivers/infiniband/hw/ocrdma/ocrdma_stats.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Thanks,
Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

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Re: [PATCH] IB/ocrdma: fix out of bounds access to local buffer

[Doug Ledford]

On Mon, 2017-05-01 at 11:57 +0300, Leon Romanovsky wrote:
> On Mon, May 01, 2017 at 03:41:16PM +0900, Michael Mera wrote:
> > 
> > In write to debugfs file 'resource_stats' the local buffer
> > 'tmp_str' is
> > written at index 'count-1' where 'count' is the size of the write,
> > so
> > potentially 0.
> > 
> > This patch filters odd values for the write size/position to avoid
> > this
> > type of problem.
> > 
> > Signed-off-by: Michael Mera <dev-5Y08+B5RRAgbhb6IIWwbbQ@public.gmane.org>
> > ---
> >  drivers/infiniband/hw/ocrdma/ocrdma_stats.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> 
> Thanks,
> Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

Thanks, applied.

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