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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v7 2/6] bpf: refactor masks for ADJ_ROOM flags and encap validation Date: Wed, 12 Aug 2026 09:31:11 +0100 Message-Id: <20260812083115.73100-3-nhudson@akamai.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260812083115.73100-1-nhudson@akamai.com> References: <20260812083115.73100-1-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:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-12_02,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 spamscore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2606160000 definitions=main-2608120066 X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDA2NyBTYWx0ZWRfX4wVlaJScV0Kv KFjDjqtqqVWeXGJMglwA8kc0dobGeBNpX2VxG2WYR6yR0Vtm3unyK4ouQLWp2md3h4QAojekt1R xYc3eLduImX4GZ8X3GxdXQ5Io1dgb1k= X-Proofpoint-GUID: tMckkw9m_tsG1Z0PzR5PYbVxy2TtHS12 X-Authority-Analysis: v=2.4 cv=Cf84Irrl c=1 sm=1 tr=0 ts=6a7c2f5f cx=c_pps a=StLZT/nZ0R8Xs+spdojYmg==:117 a=StLZT/nZ0R8Xs+spdojYmg==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Ifg-1AOnLHOf1gn6spyb:22 a=KDzEjHMMTas96-nIEKpj:22 a=X7Ea-ya5AAAA:8 a=1XWaLZrsAAAA:8 a=F30QDbW3dBX7F3vXnksA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDA2NyBTYWx0ZWRfX7WXsLjxvfVGh orKA2Pg/wGMUFnIpeK8hHVd2GnaIxkMGUQ+0Jp62evHCdQ0kDwuQ6rj3D9NjmZuM5CBAkALNc9b bKKM/b3NmKBd1/rg+6DLjZHZrpbwd4qgUXUSUKQLQTW96XCQRhxc/th+qyRgRvqTHA/72icyTe+ MnRqvfw8wl0PEQLPWvtDSBnzEhRY2/TuGHYQnjQXkw28RZctvtZcD19Q5Hq0pt+J1lcLA12xFIr RMZ92QBHEXozEq0ZjRnLdOMHQBqitxrfb/D+BLO6Oc6DueXu0UldOR1bvtLuvOsk6/CTUtOvBia /GvdvScB1Yss2V0K6reXekCBOzeDzlR3jsFbLz9/Dvp1Bohd/lXZx3Yss/EmpbhTiu91dU+vJ0B oxbbelO2JrajRtik+XxnFEGvObu7kZJ7uj/z18g1m44RUA4w5IBdnAXueGWrdHzhprnju0ivO6i Yv8XmS9IcEQItjwngnA== X-Proofpoint-ORIG-GUID: tMckkw9m_tsG1Z0PzR5PYbVxy2TtHS12 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-12_02,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 clxscore=1011 malwarescore=0 adultscore=0 suspectscore=0 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606160001 definitions=main-2608120067 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 Reviewed-by: Willem de Bruijn --- 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 3423734124a5..89e516049c85 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3572,14 +3572,19 @@ 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) @@ -3702,8 +3707,8 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, bool decap = flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK; 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; @@ -3802,8 +3807,7 @@ 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; @@ -3822,20 +3826,20 @@ 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