Commit 5c894879 authored by Russell King (Oracle)'s avatar Russell King (Oracle) Committed by Jakub Kicinski
Browse files

net: stmmac: ptp: limit n_per_out 



ptp_clock_ops.n_per_out sets the number of PPS outputs, which the PTP
subsystem uses to validate userspace input, such as the index number
used in a PTP_CLK_REQ_PEROUT request.

stmmac_enable() uses this to index the priv->pps array, which is an
array of size STMMAC_PPS_MAX. ptp_clock_ops.n_per_out is initialised
using priv->dma_cap.pps_out_num, which is a three bit field read from
hardware.

Documentation that I've checked suggests that values >= 5 are reserved,
but that doesn't mean such values won't appear, and if they do, we
can overrun the priv->pps array in stmmac_enable().

stmmac_ptp_register() has protection against this in its loop, but it
doesn't act to limit ptp_clock_ops.n_per_out.

Fix this by introducing a local variable, pps_out_num which is limited
to STMMAC_PPS_MAX, and use that when initialising the array and setting
priv->ptp_clock_ops.n_per_out. Print a warning when we limit the number
of outputs.

Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vvBhn-0000000ArCg-4C4u@rmk-PC.armlinux.org.uk


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 0314e382

drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

+11 −6
Original line number Diff line number Diff line
@@ -334,14 +334,19 @@ const struct ptp_clock_info dwmac1000_ptp_clock_ops = { 
 */

void stmmac_ptp_register(struct stmmac_priv *priv)

{

	unsigned int pps_out_num = priv->dma_cap.pps_out_num;

	int i;



	for (i = 0; i < priv->dma_cap.pps_out_num; i++) {

		if (i >= STMMAC_PPS_MAX)

			break;

		priv->pps[i].available = true;

	if (pps_out_num > STMMAC_PPS_MAX) {

		dev_warn(priv->device,

			 "pps outputs (%u) exceeds driver maximum, limiting to %u\n",

			 pps_out_num, STMMAC_PPS_MAX);

		pps_out_num = STMMAC_PPS_MAX;

	}



	for (i = 0; i < pps_out_num; i++)

		priv->pps[i].available = true;



	/* Calculate the clock domain crossing (CDC) error if necessary */

	priv->plat->cdc_error_adj = 0;

	if (priv->plat->core_type == DWMAC_CORE_GMAC4)
@@ -350,8 +355,8 @@ void stmmac_ptp_register(struct stmmac_priv *priv) 
	/* Update the ptp clock parameters based on feature discovery, when

	 * available

	 */

	if (priv->dma_cap.pps_out_num)

		priv->ptp_clock_ops.n_per_out = priv->dma_cap.pps_out_num;

	if (pps_out_num)

		priv->ptp_clock_ops.n_per_out = pps_out_num;



	if (priv->dma_cap.aux_snapshot_n)

		priv->ptp_clock_ops.n_ext_ts = priv->dma_cap.aux_snapshot_n;