[Drbd-dev] [PATCH] drivers:block:drbd:drbd_state:fix null-pointer dereference
lars.ellenberg at linbit.com
Tue Apr 25 09:06:02 CEST 2017
On Mon, Apr 24, 2017 at 11:35:18PM -0700, Heloise wrote:
> Signed-off-by: Heloise <os at iscas.ac.cn>
> In is_valid_state(), there is NULL validation for the variable nc
> "if (nc)". However,the code will continue to execute when nc is NULL.
> nc->verify_alg is used in subsequent code, which may cause
> null-pointer dereference, fix it.
> drivers/block/drbd/drbd_state.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
> index eea0c4a..1963b83 100644
> --- a/drivers/block/drbd/drbd_state.c
> +++ b/drivers/block/drbd/drbd_state.c
> @@ -845,7 +845,7 @@ is_valid_state(struct drbd_device *device, union drbd_state ns)
> rv = SS_CONNECTED_OUTDATES;
> else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
> - (nc->verify_alg == 0))
> + (nc != NULL && nc->verify_alg == 0))
What the static checker cannot know:
ns.conn != C_STANDALONE implies nc != NULL.
But if you feel like it, the additional check won't hurt.
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