From: Greg Kroah-Hartman Date: Mon, 26 Feb 2024 18:00:12 +0000 (+0100) Subject: 6.6-stable patches X-Git-Tag: v4.19.308~36 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d09c6a196712ed63d2e20c97423f9ecd7ddadcfc;p=thirdparty%2Fkernel%2Fstable-queue.git 6.6-stable patches added patches: bpf-derive-source-ip-addr-via-bpf_-_fib_lookup.patch --- diff --git a/queue-6.6/bpf-derive-source-ip-addr-via-bpf_-_fib_lookup.patch b/queue-6.6/bpf-derive-source-ip-addr-via-bpf_-_fib_lookup.patch new file mode 100644 index 00000000000..486774a7bad --- /dev/null +++ b/queue-6.6/bpf-derive-source-ip-addr-via-bpf_-_fib_lookup.patch @@ -0,0 +1,199 @@ +From dab4e1f06cabb6834de14264394ccab197007302 Mon Sep 17 00:00:00 2001 +From: Martynas Pumputis +Date: Sat, 7 Oct 2023 10:14:14 +0200 +Subject: bpf: Derive source IP addr via bpf_*_fib_lookup() + +From: Martynas Pumputis + +commit dab4e1f06cabb6834de14264394ccab197007302 upstream. + +Extend the bpf_fib_lookup() helper by making it to return the source +IPv4/IPv6 address if the BPF_FIB_LOOKUP_SRC flag is set. + +For example, the following snippet can be used to derive the desired +source IP address: + + struct bpf_fib_lookup p = { .ipv4_dst = ip4->daddr }; + + ret = bpf_skb_fib_lookup(skb, p, sizeof(p), + BPF_FIB_LOOKUP_SRC | BPF_FIB_LOOKUP_SKIP_NEIGH); + if (ret != BPF_FIB_LKUP_RET_SUCCESS) + return TC_ACT_SHOT; + + /* the p.ipv4_src now contains the source address */ + +The inability to derive the proper source address may cause malfunctions +in BPF-based dataplanes for hosts containing netdevs with more than one +routable IP address or for multi-homed hosts. + +For example, Cilium implements packet masquerading in BPF. If an +egressing netdev to which the Cilium's BPF prog is attached has +multiple IP addresses, then only one [hardcoded] IP address can be used for +masquerading. This breaks connectivity if any other IP address should have +been selected instead, for example, when a public and private addresses +are attached to the same egress interface. + +The change was tested with Cilium [1]. + +Nikolay Aleksandrov helped to figure out the IPv6 addr selection. + +[1]: https://github.com/cilium/cilium/pull/28283 + +Signed-off-by: Martynas Pumputis +Link: https://lore.kernel.org/r/20231007081415.33502-2-m@lambda.lt +Signed-off-by: Martin KaFai Lau +Cc: Daniel Borkmann +Signed-off-by: Greg Kroah-Hartman +--- + include/net/ipv6_stubs.h | 5 +++++ + include/uapi/linux/bpf.h | 10 ++++++++++ + net/core/filter.c | 18 +++++++++++++++++- + net/ipv6/af_inet6.c | 1 + + tools/include/uapi/linux/bpf.h | 10 ++++++++++ + 5 files changed, 43 insertions(+), 1 deletion(-) + +--- a/include/net/ipv6_stubs.h ++++ b/include/net/ipv6_stubs.h +@@ -85,6 +85,11 @@ struct ipv6_bpf_stub { + sockptr_t optval, unsigned int optlen); + int (*ipv6_getsockopt)(struct sock *sk, int level, int optname, + sockptr_t optval, sockptr_t optlen); ++ int (*ipv6_dev_get_saddr)(struct net *net, ++ const struct net_device *dst_dev, ++ const struct in6_addr *daddr, ++ unsigned int prefs, ++ struct in6_addr *saddr); + }; + extern const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly; + +--- a/include/uapi/linux/bpf.h ++++ b/include/uapi/linux/bpf.h +@@ -3257,6 +3257,11 @@ union bpf_attr { + * and *params*->smac will not be set as output. A common + * use case is to call **bpf_redirect_neigh**\ () after + * doing **bpf_fib_lookup**\ (). ++ * **BPF_FIB_LOOKUP_SRC** ++ * Derive and set source IP addr in *params*->ipv{4,6}_src ++ * for the nexthop. If the src addr cannot be derived, ++ * **BPF_FIB_LKUP_RET_NO_SRC_ADDR** is returned. In this ++ * case, *params*->dmac and *params*->smac are not set either. + * + * *ctx* is either **struct xdp_md** for XDP programs or + * **struct sk_buff** tc cls_act programs. +@@ -6956,6 +6961,7 @@ enum { + BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), + BPF_FIB_LOOKUP_TBID = (1U << 3), ++ BPF_FIB_LOOKUP_SRC = (1U << 4), + }; + + enum { +@@ -6968,6 +6974,7 @@ enum { + BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */ + BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */ + BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */ ++ BPF_FIB_LKUP_RET_NO_SRC_ADDR, /* failed to derive IP src addr */ + }; + + struct bpf_fib_lookup { +@@ -7002,6 +7009,9 @@ struct bpf_fib_lookup { + __u32 rt_metric; + }; + ++ /* input: source address to consider for lookup ++ * output: source address result from lookup ++ */ + union { + __be32 ipv4_src; + __u32 ipv6_src[4]; /* in6_addr; network order */ +--- a/net/core/filter.c ++++ b/net/core/filter.c +@@ -5903,6 +5903,9 @@ static int bpf_ipv4_fib_lookup(struct ne + params->rt_metric = res.fi->fib_priority; + params->ifindex = dev->ifindex; + ++ if (flags & BPF_FIB_LOOKUP_SRC) ++ params->ipv4_src = fib_result_prefsrc(net, &res); ++ + /* xdp and cls_bpf programs are run in RCU-bh so + * rcu_read_lock_bh is not needed here + */ +@@ -6045,6 +6048,18 @@ static int bpf_ipv6_fib_lookup(struct ne + params->rt_metric = res.f6i->fib6_metric; + params->ifindex = dev->ifindex; + ++ if (flags & BPF_FIB_LOOKUP_SRC) { ++ if (res.f6i->fib6_prefsrc.plen) { ++ *src = res.f6i->fib6_prefsrc.addr; ++ } else { ++ err = ipv6_bpf_stub->ipv6_dev_get_saddr(net, dev, ++ &fl6.daddr, 0, ++ src); ++ if (err) ++ return BPF_FIB_LKUP_RET_NO_SRC_ADDR; ++ } ++ } ++ + if (flags & BPF_FIB_LOOKUP_SKIP_NEIGH) + goto set_fwd_params; + +@@ -6063,7 +6078,8 @@ set_fwd_params: + #endif + + #define BPF_FIB_LOOKUP_MASK (BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT | \ +- BPF_FIB_LOOKUP_SKIP_NEIGH | BPF_FIB_LOOKUP_TBID) ++ BPF_FIB_LOOKUP_SKIP_NEIGH | BPF_FIB_LOOKUP_TBID | \ ++ BPF_FIB_LOOKUP_SRC) + + BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx, + struct bpf_fib_lookup *, params, int, plen, u32, flags) +--- a/net/ipv6/af_inet6.c ++++ b/net/ipv6/af_inet6.c +@@ -1064,6 +1064,7 @@ static const struct ipv6_bpf_stub ipv6_b + .udp6_lib_lookup = __udp6_lib_lookup, + .ipv6_setsockopt = do_ipv6_setsockopt, + .ipv6_getsockopt = do_ipv6_getsockopt, ++ .ipv6_dev_get_saddr = ipv6_dev_get_saddr, + }; + + static int __init inet6_init(void) +--- a/tools/include/uapi/linux/bpf.h ++++ b/tools/include/uapi/linux/bpf.h +@@ -3257,6 +3257,11 @@ union bpf_attr { + * and *params*->smac will not be set as output. A common + * use case is to call **bpf_redirect_neigh**\ () after + * doing **bpf_fib_lookup**\ (). ++ * **BPF_FIB_LOOKUP_SRC** ++ * Derive and set source IP addr in *params*->ipv{4,6}_src ++ * for the nexthop. If the src addr cannot be derived, ++ * **BPF_FIB_LKUP_RET_NO_SRC_ADDR** is returned. In this ++ * case, *params*->dmac and *params*->smac are not set either. + * + * *ctx* is either **struct xdp_md** for XDP programs or + * **struct sk_buff** tc cls_act programs. +@@ -6956,6 +6961,7 @@ enum { + BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), + BPF_FIB_LOOKUP_TBID = (1U << 3), ++ BPF_FIB_LOOKUP_SRC = (1U << 4), + }; + + enum { +@@ -6968,6 +6974,7 @@ enum { + BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */ + BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */ + BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */ ++ BPF_FIB_LKUP_RET_NO_SRC_ADDR, /* failed to derive IP src addr */ + }; + + struct bpf_fib_lookup { +@@ -7002,6 +7009,9 @@ struct bpf_fib_lookup { + __u32 rt_metric; + }; + ++ /* input: source address to consider for lookup ++ * output: source address result from lookup ++ */ + union { + __be32 ipv4_src; + __u32 ipv6_src[4]; /* in6_addr; network order */ diff --git a/queue-6.6/series b/queue-6.6/series index 69218bf8612..4e6261b664d 100644 --- a/queue-6.6/series +++ b/queue-6.6/series @@ -207,3 +207,4 @@ drm-amd-display-avoid-enum-conversion-warning.patch drm-amd-display-fix-buffer-overflow-in-get_host_router_total_dp_tunnel_bw.patch revert-drm-amd-display-increased-min_dcfclk_mhz-and-min_fclk_mhz.patch xen-events-fix-error-code-in-xen_bind_pirq_msi_to_irq.patch +bpf-derive-source-ip-addr-via-bpf_-_fib_lookup.patch