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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: [PATCH v6 2/6] bpf: refactor masks for ADJ_ROOM flags and encap validation Date: Mon, 4 May 2026 11:17:55 +0100 Message-Id: <20260504101759.3319427-3-nhudson@akamai.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260504101759.3319427-1-nhudson@akamai.com> References: <20260504101759.3319427-1-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=2026-05-04_03,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 bulkscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2604200000 definitions=main-2605040108 X-Proofpoint-ORIG-GUID: sFZare3zQ0uy8-THtK2stweilqJAtw-j X-Authority-Analysis: v=2.4 cv=dovrzVg4 c=1 sm=1 tr=0 ts=69f8725f cx=c_pps a=StLZT/nZ0R8Xs+spdojYmg==:117 a=StLZT/nZ0R8Xs+spdojYmg==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Ifg-1AOnLHOf1gn6spyb:22 a=BYUV7c42er6_Rx9bq0XK:22 a=X7Ea-ya5AAAA:8 a=HNUbdPRRxlDDBVXTR2oA:9 X-Proofpoint-GUID: sFZare3zQ0uy8-THtK2stweilqJAtw-j X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTA0MDEwOSBTYWx0ZWRfX42rC6XHDdedp 2ha/ufZa24X1pLyZ7TWYFrBODV2rc9LMpo50aYWb9vQk8PZ1gQbMuAA8x0fEN+CUSgTSe8vePlo uUfGVphPU4SaKcjNAq8Oe7AbuASfMOAWOVzjWNnWjCg3Hd1q+2+5i3S4coQFxINDy1NAAAtrWjY nr6ni5DNX/4K2H0Et8EvCmkemmT0uHDIIE1SEkt5/mf4kOsNxLyd3QeqDnVim0iJAg9UWYNuJIQ JHQfz3g/SiWfvS7AGUeFJPJlQYDhYn0hqc/Xt+UEtEPNodj48JiZy8r9RFfpLkUC03nJ0PqSf45 aYWDq3r+IJCmZOI+JBA+jHNUWpxgjU0URb22e1jO5w08i7fYqr6JB1jzqRJZ2G551/A9E2/Xrw5 U8rP9Wy2xYPrNnJI7A3ek20ZeoTCLTa7lfP/WfRi1E3dPxiwNNYteCaHI/lemRqiN1tWW89prNK 7szx0kHPNrRYVM3VZKw== 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=2026-05-04_03,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 malwarescore=0 bulkscore=0 impostorscore=0 phishscore=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 clxscore=1015 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605040109 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 80a3b702a2d4..02d3947cca32 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3484,14 +3484,19 @@ 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) @@ -3614,8 +3619,8 @@ 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; @@ -3714,8 +3719,7 @@ 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; @@ -3734,20 +3738,20 @@ 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