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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v4 2/6] bpf: refactor masks for ADJ_ROOM flags and encap validation Date: Thu, 16 Apr 2026 08:55:10 +0100 Message-Id: <20260416075514.927101-3-nhudson@akamai.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260416075514.927101-1-nhudson@akamai.com> References: <20260416075514.927101-1-nhudson@akamai.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-16_02,2026-04-13_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 spamscore=0 mlxlogscore=999 lowpriorityscore=0 adultscore=0 suspectscore=0 malwarescore=0 bulkscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2604070000 definitions=main-2604160071 X-Authority-Analysis: v=2.4 cv=fKsJG5ae c=1 sm=1 tr=0 ts=69e095ea cx=c_pps a=NpDlK6FjLPvvy7XAFEyJFw==:117 a=NpDlK6FjLPvvy7XAFEyJFw==:17 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Ifg-1AOnLHOf1gn6spyb:22 a=5uIk5skAYop0meUMGpPt:22 a=X7Ea-ya5AAAA:8 a=XTcGtYan5i681LpXN6wA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDE2MDA3MyBTYWx0ZWRfX14lAy8Tgui15 //DhoIprac7ic6PBlgY5Q0eO/BxonUXKzpHbNXQBe1Kb63XTKeg/uJ6B9ZciHeXm5eTa/Q8m+9k KFKKUijdw2SM4Tr8RX1l7XmEpCIh0PYW1sP7E/SLzQeKmIJsqPGEKB2P5G/8owRGgFbS+8dQfTF kTvO94szxl8G4yU3KuGjQturbjLj2fcPjoEnUmixbAChrkQYNC9MkJXkPkEAIOnbFPb19qWYLXT umlU6QeFYPETsmO17ihmm0Yc6FzP9ximVSJSTWlUHGu0k3+wBgaW0gWbvy5EDak/DmQU5+HKTMp hPg7ojQ9wTc1ptbrHfMBpn61n1qPxtCnGwK+5GpCc+LbjPJH/42iiR91z2ChQl5lK+yOY70fILu RBexWDHu1k+MYfpFi2mSK5/sFJmDtmQVAcIYaghmk97ehKyP/M7IH1YCE+YoU0HeMARPTCEIjMe 8kOXbiDRsbBJMf9uFGw== X-Proofpoint-GUID: R7xemJ62Bu0xBVX9NJQuJ-tdP3JHa9L9 X-Proofpoint-ORIG-GUID: R7xemJ62Bu0xBVX9NJQuJ-tdP3JHa9L9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-16_02,2026-04-13_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 clxscore=1015 suspectscore=0 malwarescore=0 impostorscore=0 bulkscore=0 lowpriorityscore=0 spamscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604070000 definitions=main-2604160073 Refactor the helper masks for bpf_skb_adjust_room() flags to simplify validation logic and introduce: - BPF_F_ADJ_ROOM_ENCAP_MASK - BPF_F_ADJ_ROOM_DECAP_MASK Refactor existing validation checks in bpf_skb_net_shrink() and bpf_skb_adjust_room() to use the new masks (no behavior change). This is in preparation for supporting the new decap flags. Co-developed-by: Max Tottenham Signed-off-by: Max Tottenham Co-developed-by: Anna Glasgall Signed-off-by: Anna Glasgall Signed-off-by: Nick Hudson --- --- net/core/filter.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 78b548158fb0..4e860da4381d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3490,14 +3490,19 @@ static u32 bpf_skb_net_base_len(const struct sk_buff *skb) #define BPF_F_ADJ_ROOM_DECAP_L3_MASK (BPF_F_ADJ_ROOM_DECAP_L3_IPV4 | \ BPF_F_ADJ_ROOM_DECAP_L3_IPV6) -#define BPF_F_ADJ_ROOM_MASK (BPF_F_ADJ_ROOM_FIXED_GSO | \ - BPF_F_ADJ_ROOM_ENCAP_L3_MASK | \ +#define BPF_F_ADJ_ROOM_ENCAP_MASK (BPF_F_ADJ_ROOM_ENCAP_L3_MASK | \ BPF_F_ADJ_ROOM_ENCAP_L4_GRE | \ BPF_F_ADJ_ROOM_ENCAP_L4_UDP | \ BPF_F_ADJ_ROOM_ENCAP_L2_ETH | \ BPF_F_ADJ_ROOM_ENCAP_L2( \ - BPF_ADJ_ROOM_ENCAP_L2_MASK) | \ - BPF_F_ADJ_ROOM_DECAP_L3_MASK) + BPF_ADJ_ROOM_ENCAP_L2_MASK)) + +#define BPF_F_ADJ_ROOM_DECAP_MASK (BPF_F_ADJ_ROOM_DECAP_L3_MASK) + +#define BPF_F_ADJ_ROOM_MASK (BPF_F_ADJ_ROOM_FIXED_GSO | \ + BPF_F_ADJ_ROOM_ENCAP_MASK | \ + BPF_F_ADJ_ROOM_DECAP_MASK | \ + BPF_F_ADJ_ROOM_NO_CSUM_RESET) static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff, u64 flags) @@ -3618,8 +3623,8 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, { int ret; - if (unlikely(flags & ~(BPF_F_ADJ_ROOM_FIXED_GSO | - BPF_F_ADJ_ROOM_DECAP_L3_MASK | + if (unlikely(flags & ~(BPF_F_ADJ_ROOM_DECAP_MASK | + BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_NO_CSUM_RESET))) return -EINVAL; @@ -3715,8 +3720,7 @@ BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff, u32 off; int ret; - if (unlikely(flags & ~(BPF_F_ADJ_ROOM_MASK | - BPF_F_ADJ_ROOM_NO_CSUM_RESET))) + if (unlikely(flags & ~BPF_F_ADJ_ROOM_MASK)) return -EINVAL; if (unlikely(len_diff_abs > 0xfffU)) return -EFAULT; @@ -3735,20 +3739,20 @@ BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff, return -ENOTSUPP; } - if (flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK) { + if (flags & BPF_F_ADJ_ROOM_DECAP_MASK) { if (!shrink) return -EINVAL; - switch (flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK) { - case BPF_F_ADJ_ROOM_DECAP_L3_IPV4: + /* Reject mutually exclusive decap flag pairs. */ + if ((flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK) == + BPF_F_ADJ_ROOM_DECAP_L3_MASK) + return -EINVAL; + + if (flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV4) len_min = sizeof(struct iphdr); - break; - case BPF_F_ADJ_ROOM_DECAP_L3_IPV6: + + if (flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV6) len_min = sizeof(struct ipv6hdr); - break; - default: - return -EINVAL; - } } len_cur = skb->len - skb_network_offset(skb); -- 2.34.1