The driver obtains sw_attr.num_ifs from firmware via dpsw_get_attributes() but never validates it against DPSW_MAX_IF (64). This value controls iteration in dpaa2_switch_fdb_get_flood_cfg(), which writes port indices into the fixed-size cfg->if_id[DPSW_MAX_IF] array. When firmware reports num_ifs >= 64, the loop can write past the array bounds. Add a bound check for num_ifs in dpaa2_switch_init(). dpaa2_switch_fdb_get_flood_cfg() appends the control interface (port num_ifs) after all matched ports. When num_ifs == DPSW_MAX_IF and all ports match the flood filter, the loop fills all 64 slots and the control interface write overflows by one entry. The check uses >= because num_ifs == DPSW_MAX_IF is also functionally broken. build_if_id_bitmap() silently drops any ID >= 64: if (id[i] < DPSW_MAX_IF) bmap[id[i] / 64] |= ... Fixes: 539dda3c5d19 ("staging: dpaa2-switch: properly setup switching domains") Signed-off-by: Junrui Luo --- Changes in v2: - Drop self-referential Reported-by tags - Update Fixes tag to reference 539dda3c5d19 - Expand the commit description - Link to v1: https://lore.kernel.org/all/SYBPR01MB788110DFE66BA1A5CE7E594FAF6DA@SYBPR01MB7881.ausprd01.prod.outlook.com/ --- drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c index 66240c340492..78e21b46a5ba 100644 --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c @@ -3034,6 +3034,13 @@ static int dpaa2_switch_init(struct fsl_mc_device *sw_dev) goto err_close; } + if (ethsw->sw_attr.num_ifs >= DPSW_MAX_IF) { + dev_err(dev, "DPSW num_ifs %u exceeds max %u\n", + ethsw->sw_attr.num_ifs, DPSW_MAX_IF); + err = -EINVAL; + goto err_close; + } + err = dpsw_get_api_version(ethsw->mc_io, 0, ðsw->major, ðsw->minor); --- base-commit: 9702969978695d9a699a1f34771580cdbb153b33 change-id: 20260224-fixes-a33979dd5060 Best regards, -- Junrui Luo