From: Michael Mera <dev@xxxxxxxxxxxxxxx> commit 062d0f22a30c39840ea49b72cfcfc1aa4cc538fa upstream. 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@xxxxxxxxxxxxxxx> Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx> Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx> --- Please cherry-pick it on 4.4.y as well. Not applicable for 3.18.y 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 265943069b35..84349d976162 100644 --- a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c +++ b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c @@ -645,7 +645,7 @@ 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)) -- 2.7.4
