diff options
| -rw-r--r-- | include/linux/bpf.h | 1 | ||||
| -rw-r--r-- | include/linux/bpf_types.h | 1 | ||||
| -rw-r--r-- | include/linux/skbuff.h | 7 | ||||
| -rw-r--r-- | include/net/net_namespace.h | 3 | ||||
| -rw-r--r-- | include/net/sch_generic.h | 12 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 26 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 8 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 32 | ||||
| -rw-r--r-- | net/core/filter.c | 70 | ||||
| -rw-r--r-- | net/core/flow_dissector.c | 134 |
10 files changed, 291 insertions, 3 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 523481a3471b..988a00797bcd 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -212,6 +212,7 @@ enum bpf_reg_type { PTR_TO_PACKET_META, /* skb->data - meta_len */ PTR_TO_PACKET, /* reg points to skb->data */ PTR_TO_PACKET_END, /* skb->data + headlen */ + PTR_TO_FLOW_KEYS, /* reg points to bpf_flow_keys */ }; /* The information passed from prog-specific *_is_valid_access diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index cd26c090e7c0..22083712dd18 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -32,6 +32,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2) #ifdef CONFIG_INET BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport) #endif +BPF_PROG_TYPE(BPF_PROG_TYPE_FLOW_DISSECTOR, flow_dissector) BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 17a13e4785fc..ce0e863f02a2 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -243,6 +243,8 @@ struct scatterlist; struct pipe_inode_info; struct iov_iter; struct napi_struct; +struct bpf_prog; +union bpf_attr; #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) struct nf_conntrack { @@ -1192,6 +1194,11 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector, const struct flow_dissector_key *key, unsigned int key_count); +int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, + struct bpf_prog *prog); + +int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr); + bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector *flow_dissector, void *target_container, diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 9b5fdc50519a..99d4148e0f90 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -43,6 +43,7 @@ struct ctl_table_header; struct net_generic; struct uevent_sock; struct netns_ipvs; +struct bpf_prog; #define NETDEV_HASHBITS 8 @@ -145,6 +146,8 @@ struct net { #endif struct net_generic __rcu *gen; + struct bpf_prog __rcu *flow_dissector_prog; + /* Note : following structs are cache line aligned */ #ifdef CONFIG_XFRM struct netns_xfrm xfrm; diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index a6d00093f35e..1b81ba85fd2d 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -19,6 +19,7 @@ struct Qdisc_ops; struct qdisc_walker; struct tcf_walker; struct module; +struct bpf_flow_keys; typedef int tc_setup_cb_t(enum tc_setup_type type, void *type_data, void *cb_priv); @@ -307,9 +308,14 @@ struct tcf_proto { }; struct qdisc_skb_cb { - unsigned int pkt_len; - u16 slave_dev_queue_mapping; - u16 tc_classid; + union { + struct { + unsigned int pkt_len; + u16 slave_dev_queue_mapping; + u16 tc_classid; + }; + struct bpf_flow_keys *flow_keys; + }; #define QDISC_CB_PRIV_LEN 20 unsigned char data[QDISC_CB_PRIV_LEN]; }; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 66917a4eba27..aa5ccd2385ed 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -152,6 +152,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_LWT_SEG6LOCAL, BPF_PROG_TYPE_LIRC_MODE2, BPF_PROG_TYPE_SK_REUSEPORT, + BPF_PROG_TYPE_FLOW_DISSECTOR, }; enum bpf_attach_type { @@ -172,6 +173,7 @@ enum bpf_attach_type { BPF_CGROUP_UDP4_SENDMSG, BPF_CGROUP_UDP6_SENDMSG, BPF_LIRC_MODE2, + BPF_FLOW_DISSECTOR, __MAX_BPF_ATTACH_TYPE }; @@ -2333,6 +2335,7 @@ struct __sk_buff { /* ... here. */ __u32 data_meta; + struct bpf_flow_keys *flow_keys; }; struct bpf_tunnel_key { @@ -2778,4 +2781,27 @@ enum bpf_task_fd_type { BPF_FD_TYPE_URETPROBE, /* filename + offset */ }; +struct bpf_flow_keys { + __u16 nhoff; + __u16 thoff; + __u16 addr_proto; /* ETH_P_* of valid addrs */ + __u8 is_frag; + __u8 is_first_frag; + __u8 is_encap; + __u8 ip_proto; + __be16 n_proto; + __be16 sport; + __be16 dport; + union { + struct { + __be32 ipv4_src; + __be32 ipv4_dst; + }; + struct { + __u32 ipv6_src[4]; /* in6_addr; network order */ + __u32 ipv6_dst[4]; /* in6_addr; network order */ + }; + }; +}; + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 3c9636f03bb2..b3c2d09bcf7a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1615,6 +1615,9 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_LIRC_MODE2: ptype = BPF_PROG_TYPE_LIRC_MODE2; break; + case BPF_FLOW_DISSECTOR: + ptype = BPF_PROG_TYPE_FLOW_DISSECTOR; + break; default: return -EINVAL; } @@ -1636,6 +1639,9 @@ static int bpf_prog_attach(const union bpf_attr *attr) case BPF_PROG_TYPE_LIRC_MODE2: ret = lirc_prog_attach(attr, prog); break; + case BPF_PROG_TYPE_FLOW_DISSECTOR: + ret = skb_flow_dissector_bpf_prog_attach(attr, prog); + break; default: ret = cgroup_bpf_prog_attach(attr, ptype, prog); } @@ -1688,6 +1694,8 @@ static int bpf_prog_detach(const union bpf_attr *attr) return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, NULL); case BPF_LIRC_MODE2: return lirc_prog_detach(attr); + case BPF_FLOW_DISSECTOR: + return skb_flow_dissector_bpf_prog_detach(attr); default: return -EINVAL; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6ff1bac1795d..8ccbff4fff93 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -261,6 +261,7 @@ static const char * const reg_type_str[] = { [PTR_TO_PACKET] = "pkt", [PTR_TO_PACKET_META] = "pkt_meta", [PTR_TO_PACKET_END] = "pkt_end", + [PTR_TO_FLOW_KEYS] = "flow_keys", }; static char slot_type_char[] = { @@ -965,6 +966,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type) case PTR_TO_PACKET: case PTR_TO_PACKET_META: case PTR_TO_PACKET_END: + case PTR_TO_FLOW_KEYS: case CONST_PTR_TO_MAP: return true; default: @@ -1238,6 +1240,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, case BPF_PROG_TYPE_LWT_XMIT: case BPF_PROG_TYPE_SK_SKB: case BPF_PROG_TYPE_SK_MSG: + case BPF_PROG_TYPE_FLOW_DISSECTOR: if (meta) return meta->pkt_access; @@ -1321,6 +1324,18 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, return -EACCES; } +static int check_flow_keys_access(struct bpf_verifier_env *env, int off, + int size) +{ + if (size < 0 || off < 0 || + (u64)off + size > sizeof(struct bpf_flow_keys)) { + verbose(env, "invalid access to flow keys off=%d size=%d\n", + off, size); + return -EACCES; + } + return 0; +} + static bool __is_pointer_value(bool allow_ptr_leaks, const struct bpf_reg_state *reg) { @@ -1422,6 +1437,9 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, * right in front, treat it the very same way. */ return check_pkt_ptr_alignment(env, reg, off, size, strict); + case PTR_TO_FLOW_KEYS: + pointer_desc = "flow keys "; + break; case PTR_TO_MAP_VALUE: pointer_desc = "value "; break; @@ -1692,6 +1710,17 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn err = check_packet_access(env, regno, off, size, false); if (!err && t == BPF_READ && value_regno >= 0) mark_reg_unknown(env, regs, value_regno); + } else if (reg->type == PTR_TO_FLOW_KEYS) { + if (t == BPF_WRITE && value_regno >= 0 && + is_pointer_value(env, value_regno)) { + verbose(env, "R%d leaks addr into flow keys\n", + value_regno); + return -EACCES; + } + + err = check_flow_keys_access(env, off, size); + if (!err && t == BPF_READ && value_regno >= 0) + mark_reg_unknown(env, regs, value_regno); } else { verbose(env, "R%d invalid mem access '%s'\n", regno, reg_type_str[reg->type]); @@ -1839,6 +1868,8 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, case PTR_TO_PACKET_META: return check_packet_access(env, regno, reg->off, access_size, zero_size_allowed); + case PTR_TO_FLOW_KEYS: + return check_flow_keys_access(env, reg->off, access_size); case PTR_TO_MAP_VALUE: return check_map_access(env, regno, reg->off, access_size, zero_size_allowed); @@ -4366,6 +4397,7 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, case PTR_TO_CTX: case CONST_PTR_TO_MAP: case PTR_TO_PACKET_END: + case PTR_TO_FLOW_KEYS: /* Only valid matches are exact, which memcmp() above * would have accepted */ diff --git a/net/core/filter.c b/net/core/filter.c index bf5b6efd369a..9cc76f134ddb 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5124,6 +5124,17 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) } static const struct bpf_func_proto * +flow_dissector_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_skb_load_bytes: + return &bpf_skb_load_bytes_proto; + default: + return bpf_base_func_proto(func_id); + } +} + +static const struct bpf_func_proto * lwt_out_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { @@ -5241,6 +5252,10 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type if (size != size_default) return false; break; + case bpf_ctx_range(struct __sk_buff, flow_keys): + if (size != sizeof(struct bpf_flow_keys *)) + return false; + break; default: /* Only narrow read access allowed for now. */ if (type == BPF_WRITE) { @@ -5266,6 +5281,7 @@ static bool sk_filter_is_valid_access(int off, int size, case bpf_ctx_range(struct __sk_buff, data): case bpf_ctx_range(struct __sk_buff, data_meta): case bpf_ctx_range(struct __sk_buff, data_end): + case bpf_ctx_range(struct __sk_buff, flow_keys): case bpf_ctx_range_till(struct __sk_buff, family, local_port): return false; } @@ -5291,6 +5307,7 @@ static bool lwt_is_valid_access(int off, int size, case bpf_ctx_range(struct __sk_buff, tc_classid): case bpf_ctx_range_till(struct __sk_buff, family, local_port): case bpf_ctx_range(struct __sk_buff, data_meta): + case bpf_ctx_range(struct __sk_buff, flow_keys): return false; } @@ -5501,6 +5518,7 @@ static bool tc_cls_act_is_valid_access(int off, int size, case bpf_ctx_range(struct __sk_buff, data_end): info->reg_type = PTR_TO_PACKET_END; break; + case bpf_ctx_range(struct __sk_buff, flow_keys): case bpf_ctx_range_till(struct __sk_buff, family, local_port): return false; } @@ -5702,6 +5720,7 @@ static bool sk_skb_is_valid_access(int off, int size, switch (off) { case bpf_ctx_range(struct __sk_buff, tc_classid): case bpf_ctx_range(struct __sk_buff, data_meta): + case bpf_ctx_range(struct __sk_buff, flow_keys): return false; } @@ -5761,6 +5780,39 @@ static bool sk_msg_is_valid_access(int off, int size, return true; } +static bool flow_dissector_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + if (type == BPF_WRITE) { + switch (off) { + case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]): + break; + default: + return false; + } + } + + switch (off) { + case bpf_ctx_range(struct __sk_buff, data): + info->reg_type = PTR_TO_PACKET; + break; + case bpf_ctx_range(struct __sk_buff, data_end): + info->reg_type = PTR_TO_PACKET_END; + break; + case bpf_ctx_range(struct __sk_buff, flow_keys): + info->reg_type = PTR_TO_FLOW_KEYS; + break; + case bpf_ctx_range(struct __sk_buff, tc_classid): + case bpf_ctx_range(struct __sk_buff, data_meta): + case bpf_ctx_range_till(struct __sk_buff, family, local_port): + return false; + } + + return bpf_skb_is_valid_access(off, size, type, prog, info); +} + static u32 bpf_convert_ctx_access(enum bpf_access_type type, const struct bpf_insn *si, struct bpf_insn *insn_buf, @@ -6055,6 +6107,15 @@ static u32 bpf_convert_ctx_access(enum bpf_access_type type, bpf_target_off(struct sock_common, skc_num, 2, target_size)); break; + + case offsetof(struct __sk_buff, flow_keys): + off = si->off; + off -= offsetof(struct __sk_buff, flow_keys); + off += offsetof(struct sk_buff, cb); + off += offsetof(struct qdisc_skb_cb, flow_keys); + *insn++ = BPF_LDX_MEM(BPF_SIZEOF(void *), si->dst_reg, + si->src_reg, off); + break; } return insn - insn_buf; @@ -7018,6 +7079,15 @@ const struct bpf_verifier_ops sk_msg_verifier_ops = { const struct bpf_prog_ops sk_msg_prog_ops = { }; +const struct bpf_verifier_ops flow_dissector_verifier_ops = { + .get_func_proto = flow_dissector_func_proto, + .is_valid_access = flow_dissector_is_valid_access, + .convert_ctx_access = bpf_convert_ctx_access, +}; + +const struct bpf_prog_ops flow_dissector_prog_ops = { +}; + int sk_detach_filter(struct sock *sk) { int ret = -ENOENT; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index ce9eeeb7c024..5c5dd74b5b3b 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -25,6 +25,9 @@ #include <net/flow_dissector.h> #include <scsi/fc/fc_fcoe.h> #include <uapi/linux/batadv_packet.h> +#include <linux/bpf.h> + +static DEFINE_MUTEX(flow_dissector_mutex); static void dissector_set_key(struct flow_dissector *flow_dissector, enum flow_dissector_key_id key_id) @@ -62,6 +65,44 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector, } EXPORT_SYMBOL(skb_flow_dissector_init); +int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, + struct bpf_prog *prog) +{ + struct bpf_prog *attached; + struct net *net; + + net = current->nsproxy->net_ns; + mutex_lock(&flow_dissector_mutex); + attached = rcu_dereference_protected(net->flow_dissector_prog, + lockdep_is_held(&flow_dissector_mutex)); + if (attached) { + /* Only one BPF program can be attached at a time */ + mutex_unlock(&flow_dissector_mutex); + return -EEXIST; + } + rcu_assign_pointer(net->flow_dissector_prog, prog); + mutex_unlock(&flow_dissector_mutex); + return 0; +} + +int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr) +{ + struct bpf_prog *attached; + struct net *net; + + net = current->nsproxy->net_ns; + mutex_lock(&flow_dissector_mutex); + attached = rcu_dereference_protected(net->flow_dissector_prog, + lockdep_is_held(&flow_dissector_mutex)); + if (!attached) { + mutex_unlock(&flow_dissector_mutex); + return -ENOENT; + } + bpf_prog_put(attached); + RCU_INIT_POINTER(net->flow_dissector_prog, NULL); + mutex_unlock(&flow_dissector_mutex); + return 0; +} /** * skb_flow_get_be16 - extract be16 entity * @skb: sk_buff to extract from @@ -588,6 +629,60 @@ static bool skb_flow_dissect_allowed(int *num_hdrs) return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS); } +static void __skb_flow_bpf_to_target(const struct bpf_flow_keys *flow_keys, + struct flow_dissector *flow_dissector, + void *target_container) +{ + struct flow_dissector_key_control *key_control; + struct flow_dissector_key_basic *key_basic; + struct flow_dissector_key_addrs *key_addrs; + struct flow_dissector_key_ports *key_ports; + + key_control = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_CONTROL, + target_container); + key_control->thoff = flow_keys->thoff; + if (flow_keys->is_frag) + key_control->flags |= FLOW_DIS_IS_FRAGMENT; + if (flow_keys->is_first_frag) + key_control->flags |= FLOW_DIS_FIRST_FRAG; + if (flow_keys->is_encap) + key_control->flags |= FLOW_DIS_ENCAPSULATION; + + key_basic = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_BASIC, + target_container); + key_basic->n_proto = flow_keys->n_proto; + key_basic->ip_proto = flow_keys->ip_proto; + + if (flow_keys->addr_proto == ETH_P_IP && + dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IPV4_ADDRS)) { + key_addrs = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_IPV4_ADDRS, + target_container); + key_addrs->v4addrs.src = flow_keys->ipv4_src; + key_addrs->v4addrs.dst = flow_keys->ipv4_dst; + key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; + } else if (flow_keys->addr_proto == ETH_P_IPV6 && + dissector_uses_key(flow_dissector, + FLOW_DISSECTOR_KEY_IPV6_ADDRS)) { + key_addrs = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_IPV6_ADDRS, + target_container); + memcpy(&key_addrs->v6addrs, &flow_keys->ipv6_src, + sizeof(key_addrs->v6addrs)); + key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; + } + + if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS)) { + key_ports = skb_flow_dissector_target(flow_dissector, + FLOW_DISSECTOR_KEY_PORTS, + target_container); + key_ports->src = flow_keys->sport; + key_ports->dst = flow_keys->dport; + } +} + /** * __skb_flow_dissect - extract the flow_keys struct and return it * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified @@ -619,6 +714,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_dissector_key_vlan *key_vlan; enum flow_dissect_ret fdret; enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX; + struct bpf_prog *attached; int num_hdrs = 0; u8 ip_proto = 0; bool ret; @@ -658,6 +754,44 @@ bool __skb_flow_dissect(const struct sk_buff *skb, FLOW_DISSECTOR_KEY_BASIC, target_container); + rcu_read_lock(); + attached = skb ? rcu_dereference(dev_net(skb->dev)->flow_dissector_prog) + : NULL; + if (attached) { + /* Note that even though the const qualifier is discarded + * throughout the execution of the BPF program, all changes(the + * control block) are reverted after the BPF program returns. + * Therefore, __skb_flow_dissect does not alter the skb. + */ + struct bpf_flow_keys flow_keys = {}; + struct bpf_skb_data_end cb_saved; + struct bpf_skb_data_end *cb; + u32 result; + + cb = (struct bpf_skb_data_end *)skb->cb; + + /* Save Control Block */ + memcpy(&cb_saved, cb, sizeof(cb_saved)); + memset(cb, 0, sizeof(cb_saved)); + + /* Pass parameters to the BPF program */ + cb->qdisc_cb.flow_keys = &flow_keys; + flow_keys.nhoff = nhoff; + + bpf_compute_data_pointers((struct sk_buff *)skb); + result = BPF_PROG_RUN(attached, skb); + + /* Restore state */ + memcpy(cb, &cb_saved, sizeof(cb_saved)); + + __skb_flow_bpf_to_target(&flow_keys, flow_dissector, + target_container); + key_control->thoff = min_t(u16, key_control->thoff, skb->len); + rcu_read_unlock(); + return result == BPF_OK; + } + rcu_read_unlock(); + if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ETH_ADDRS)) { struct ethhdr *eth = eth_hdr(skb); |