From: Gal Pressman Date: Mon, 6 Jul 2026 05:50:17 +0000 (+0300) Subject: ethtool: rss: Fix hfunc and input_xfrm parsing on big endian X-Git-Tag: v7.2-rc3~29^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b62869a81a7ce388d1fbb0fac5fa8300ea614d81;p=thirdparty%2Fkernel%2Flinux.git ethtool: rss: Fix hfunc and input_xfrm parsing on big endian ETHTOOL_A_RSS_HFUNC and ETHTOOL_A_RSS_INPUT_XFRM are NLA_U32 attributes, but ethnl_rss_set() and ethnl_rss_create_doit() parse them with ethnl_update_u8(), which reads a single byte. On little endian this happens to read the least significant byte and works as long as the value fits in a byte. On big endian it reads the most significant byte, so the requested value is parsed incorrectly. The destination fields in struct ethtool_rxfh_param are u8, so the attribute can't be read directly with ethnl_update_u32(). Cap the hfunc policy at U8_MAX so an out of range value is rejected instead of being silently truncated into the u8 field, and add ethnl_update_u8_u32() to read the full u32 and narrow it into the u8 destination. Fixes: 82ae67cbc423 ("ethtool: rss: support setting hfunc via Netlink") Fixes: d3e2c7bab124 ("ethtool: rss: support setting input-xfrm via Netlink") Fixes: a166ab7816c5 ("ethtool: rss: support creating contexts via Netlink") Reviewed-by: Dragos Tatulea Reviewed-by: Nimrod Oren Signed-off-by: Gal Pressman Link: https://patch.msgid.link/20260706055017.3355806-1-gal@nvidia.com Signed-off-by: Paolo Abeni --- diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h index 4ca2eca2e94b..3e969a070f9f 100644 --- a/net/ethtool/netlink.h +++ b/net/ethtool/netlink.h @@ -114,6 +114,34 @@ static inline void ethnl_update_u8(u8 *dst, const struct nlattr *attr, *mod = true; } +/** + * ethnl_update_u8_u32() - update u8 value from an NLA_U32 attribute + * @dst: value to update + * @attr: netlink attribute with new value or null + * @mod: pointer to bool for modification tracking + * + * Some attributes are NLA_U32 on the wire but are stored in a u8. Read the + * full 32-bit value from NLA_U32 netlink attribute @attr and narrow it into + * the u8 pointed to by @dst; do nothing if @attr is null. + * Bool pointed to by @mod is set to true if this function changed the value + * of *dst, otherwise it is left as is. + */ +static inline void ethnl_update_u8_u32(u8 *dst, const struct nlattr *attr, + bool *mod) +{ + u32 val; + + if (!attr) + return; + val = nla_get_u32(attr); + DEBUG_NET_WARN_ON_ONCE(val > U8_MAX); + if (*dst == val) + return; + + *dst = val; + *mod = true; +} + /** * ethnl_update_bool32() - update u32 used as bool from NLA_U8 attribute * @dst: value to update diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c index d8adc78e3775..d4a1a4724b67 100644 --- a/net/ethtool/rss.c +++ b/net/ethtool/rss.c @@ -570,7 +570,7 @@ static const struct nla_policy ethnl_rss_flows_policy[] = { const struct nla_policy ethnl_rss_set_policy[ETHTOOL_A_RSS_FLOW_HASH + 1] = { [ETHTOOL_A_RSS_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy), [ETHTOOL_A_RSS_CONTEXT] = { .type = NLA_U32, }, - [ETHTOOL_A_RSS_HFUNC] = NLA_POLICY_MIN(NLA_U32, 1), + [ETHTOOL_A_RSS_HFUNC] = NLA_POLICY_RANGE(NLA_U32, 1, U8_MAX), [ETHTOOL_A_RSS_INDIR] = { .type = NLA_BINARY, }, [ETHTOOL_A_RSS_HKEY] = NLA_POLICY_MIN(NLA_BINARY, 1), [ETHTOOL_A_RSS_INPUT_XFRM] = @@ -851,7 +851,7 @@ ethnl_rss_set(struct ethnl_req_info *req_info, struct genl_info *info) indir_mod = !!tb[ETHTOOL_A_RSS_INDIR]; rxfh.hfunc = data.hfunc; - ethnl_update_u8(&rxfh.hfunc, tb[ETHTOOL_A_RSS_HFUNC], &mod); + ethnl_update_u8_u32(&rxfh.hfunc, tb[ETHTOOL_A_RSS_HFUNC], &mod); if (rxfh.hfunc == data.hfunc) rxfh.hfunc = ETH_RSS_HASH_NO_CHANGE; @@ -860,7 +860,8 @@ ethnl_rss_set(struct ethnl_req_info *req_info, struct genl_info *info) goto exit_free_indir; rxfh.input_xfrm = data.input_xfrm; - ethnl_update_u8(&rxfh.input_xfrm, tb[ETHTOOL_A_RSS_INPUT_XFRM], &mod); + ethnl_update_u8_u32(&rxfh.input_xfrm, tb[ETHTOOL_A_RSS_INPUT_XFRM], + &mod); xfrm_sym = rxfh.input_xfrm || data.input_xfrm; if (rxfh.input_xfrm == data.input_xfrm) rxfh.input_xfrm = RXH_XFRM_NO_CHANGE; @@ -934,7 +935,7 @@ const struct ethnl_request_ops ethnl_rss_request_ops = { const struct nla_policy ethnl_rss_create_policy[ETHTOOL_A_RSS_INPUT_XFRM + 1] = { [ETHTOOL_A_RSS_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy), [ETHTOOL_A_RSS_CONTEXT] = NLA_POLICY_MIN(NLA_U32, 1), - [ETHTOOL_A_RSS_HFUNC] = NLA_POLICY_MIN(NLA_U32, 1), + [ETHTOOL_A_RSS_HFUNC] = NLA_POLICY_RANGE(NLA_U32, 1, U8_MAX), [ETHTOOL_A_RSS_INDIR] = NLA_POLICY_MIN(NLA_BINARY, 1), [ETHTOOL_A_RSS_HKEY] = NLA_POLICY_MIN(NLA_BINARY, 1), [ETHTOOL_A_RSS_INPUT_XFRM] = @@ -1048,14 +1049,15 @@ int ethnl_rss_create_doit(struct sk_buff *skb, struct genl_info *info) goto exit_clean_data; indir_user_size = ret; - ethnl_update_u8(&rxfh.hfunc, tb[ETHTOOL_A_RSS_HFUNC], &mod); + ethnl_update_u8_u32(&rxfh.hfunc, tb[ETHTOOL_A_RSS_HFUNC], &mod); ret = rss_set_prep_hkey(dev, info, &data, &rxfh, &mod); if (ret) goto exit_free_indir; rxfh.input_xfrm = RXH_XFRM_NO_CHANGE; - ethnl_update_u8(&rxfh.input_xfrm, tb[ETHTOOL_A_RSS_INPUT_XFRM], &mod); + ethnl_update_u8_u32(&rxfh.input_xfrm, tb[ETHTOOL_A_RSS_INPUT_XFRM], + &mod); ctx = ethtool_rxfh_ctx_alloc(ops, data.indir_size, data.hkey_size); if (!ctx) {