6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit cdb719f4b8596d9ccee2d56d204c2c4dce982f46 ] bcm_sf2_cfp_rule_get_all() walks the whole cfp.unique bitmap into rule_locs[] without consulting nfc->rule_cnt, which is how many entries the caller had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN and the ioctl sizes the buffer from the rule_cnt userspace passes in, so once an admin has installed CFP rules any user can ask for fewer slots than there are rules and run off the end of the allocation. A rule_cnt of 0 leaves the buffer pointer NULL and the walk dereferences it. Fixes: 7318166cacad ("net: dsa: bcm_sf2: Add support for ethtool::rxnfc") Reviewed-by: Jonas Gorski Reviewed-by: Florian Fainelli Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260903032611.3000029-2-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/dsa/bcm_sf2_cfp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/dsa/bcm_sf2_cfp.c b/drivers/net/dsa/bcm_sf2_cfp.c index c4010b7bf0899..f48ac7b021f37 100644 --- a/drivers/net/dsa/bcm_sf2_cfp.c +++ b/drivers/net/dsa/bcm_sf2_cfp.c @@ -1088,6 +1088,8 @@ static int bcm_sf2_cfp_rule_get_all(struct bcm_sf2_priv *priv, unsigned int index = 1, rules_cnt = 0; for_each_set_bit_from(index, priv->cfp.unique, priv->num_cfp_rules) { + if (rules_cnt == nfc->rule_cnt) + return -EMSGSIZE; rule_locs[rules_cnt] = index; rules_cnt++; } -- 2.53.0