[PATCH v3 2/3] net: stmmac: fix l3l4 filter rejecting unsupported offload requests
From: <hidden>
Date: 2026-06-30 11:56:34
Also in:
lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Nazim Amirul <redacted>
The basic flow parser in tc_add_basic_flow() does not validate match
keys before proceeding. Unsupported offload configurations such as
partial protocol masks, non-IPv4 network proto, or non-TCP/UDP transport
proto are silently accepted instead of returning -EOPNOTSUPP.
Add validation to return -EOPNOTSUPP early for:
- No network or transport proto present in the key
- Partial protocol mask (only full mask supported)
- Network proto is not IPv4
- Transport proto is not TCP or UDP
Each rejection includes an extack message so the user knows which part
of the match is unsupported.
Also propagate -EOPNOTSUPP from tc_add_basic_flow() in tc_add_flow()
by returning it directly rather than using break. The break was silently
discarding the error for FLOW_CLS_REPLACE operations where entry->in_use
is already true, causing tc_add_flow() to return 0 (success) for
unsupported replace requests.
Fixes: 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower")
Signed-off-by: Rohan G Thomas <redacted>
Signed-off-by: Nazim Amirul <redacted>
---
Changes in v3:
- Add extack messages to each -EOPNOTSUPP return so users know which
part of the match is unsupported (Jakub Kicinski)
- Return -EOPNOTSUPP directly instead of break to avoid silently
reporting success on unsupported FLOW_CLS_REPLACE (Sashiko review)
- Patches 1/3 and 3/3 are unchanged from v2
Changes in v2:
- No changes
---
.../net/ethernet/stmicro/stmmac/stmmac_tc.c | 34 +++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index d78652718599..14cabe76e53e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c@@ -446,6 +446,7 @@ static int tc_parse_flow_actions(struct stmmac_priv *priv, } #define ETHER_TYPE_FULL_MASK cpu_to_be16(~0) +#define IP_PROTO_FULL_MASK 0xFF static int tc_add_basic_flow(struct stmmac_priv *priv, struct flow_cls_offload *cls,
@@ -461,6 +462,33 @@ static int tc_add_basic_flow(struct stmmac_priv *priv, flow_rule_match_basic(rule, &match); + /* Both network proto and transport proto not present in the key */ + if (!match.mask || !(match.mask->n_proto || match.mask->ip_proto)) { + NL_SET_ERR_MSG_MOD(cls->common.extack, + "filter must specify network or transport protocol"); + return -EOPNOTSUPP; + } + + /* If the proto is present in the key and is not full mask */ + if ((match.mask->n_proto && match.mask->n_proto != ETHER_TYPE_FULL_MASK) || + (match.mask->ip_proto && match.mask->ip_proto != IP_PROTO_FULL_MASK)) { + NL_SET_ERR_MSG_MOD(cls->common.extack, + "only full protocol mask is supported"); + return -EOPNOTSUPP; + } + + /* Network proto is present in the key and is not IPv4 */ + if (match.mask->n_proto && match.key->n_proto != cpu_to_be16(ETH_P_IP)) { + NL_SET_ERR_MSG_MOD(cls->common.extack, + "only IPv4 network protocol is supported"); + return -EOPNOTSUPP; + } + + /* Transport proto is present in the key and is not TCP or UDP */ + if (match.mask->ip_proto && + match.key->ip_proto != IPPROTO_TCP && + match.key->ip_proto != IPPROTO_UDP) { + NL_SET_ERR_MSG_MOD(cls->common.extack, + "only TCP and UDP transport protocols are supported"); + return -EOPNOTSUPP; + } + entry->ip_proto = match.key->ip_proto; return 0; }
@@ -598,11 +626,7 @@ static int tc_add_flow(struct stmmac_priv *priv, ret = tc_flow_parsers[i].fn(priv, cls, entry); if (!ret) entry->in_use = true; - else if (ret == -EOPNOTSUPP) - /* The basic flow parser will return EOPNOTSUPP, if a - * requested offload not fully supported by the hw. And - * in that case fail early. - */ - break; + else if (ret == -EOPNOTSUPP) + return ret; } if (!entry->in_use)
--
2.43.7