In the quest to remove all stack VLAs from the kernel[1], this switches the "status" stack buffer to use the existing small (8) upper bound on how many queues can be checked for DMA, and adds a sanity-check just to make sure it doesn't operate under pathological conditions.
[1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qpxydaacu1rq...@mail.gmail.com Signed-off-by: Kees Cook <keesc...@chromium.org> --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index b65e2d144698..19bdc23fa314 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2045,7 +2045,11 @@ static void stmmac_dma_interrupt(struct stmmac_priv *priv) tx_channel_count : rx_channel_count; u32 chan; bool poll_scheduled = false; - int status[channels_to_check]; + int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)]; + + /* Make sure we never check beyond our status buffer. */ + if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status))) + channels_to_check = ARRAY_SIZE(status); /* Each DMA channel can be used for rx and tx simultaneously, yet * napi_struct is embedded in struct stmmac_rx_queue rather than in a -- 2.7.4 -- Kees Cook Pixel Security
