diff options
author | Martin KaFai Lau <[email protected]> | 2023-05-19 17:45:47 -0700 |
---|---|---|
committer | Martin KaFai Lau <[email protected]> | 2023-05-19 22:44:28 -0700 |
commit | 18f558876ff0361e8ceb537cdf6fec8936ff6f72 (patch) | |
tree | 3ad42c66005ca05fd9774e0fb61e572754d4ca43 | |
parent | 9343184cb31fef673566ff37c41a9f418deb9de3 (diff) | |
parent | 1a8bc2299f4028e9bac36020ffaaec27a0dfb9c1 (diff) |
Merge branch 'bpf: Add socket destroy capability'
Aditi Ghag says:
====================
This patch set adds the capability to destroy sockets in BPF. We plan to
use the capability in Cilium to force client sockets to reconnect when
their remote load-balancing backends are deleted. The other use case is
on-the-fly policy enforcement where existing socket connections
prevented by policies need to be terminated.
The use cases, and more details around
the selected approach were presented at LPC 2022 -
https://lpc.events/event/16/contributions/1358/.
RFC discussion -
https://lore.kernel.org/netdev/CABG=zsBEh-P4NXk23eBJw7eajB5YJeRS7oPXnTAzs=yob4EMoQ@mail.gmail.com/T/#u.
v8 patch series -
https://lore.kernel.org/bpf/[email protected]/
v9 highlights:
Address review comments:
Martin:
- Rearranged the kfunc filter patch, and added the missing break
statement.
- Squashed the extended selftest/bpf patch.
Yonghong:
- Revised commit message for patch 1.
(Below notes are same as v8 patch series that are still relevant. Refer to
earlier patch series versions for other notes.)
- I hit a snag while writing the kfunc where verifier complained about the
`sock_common` type passed from TCP iterator. With kfuncs, there don't
seem to be any options available to pass BTF type hints to the verifier
(equivalent of `ARG_PTR_TO_BTF_ID_SOCK_COMMON`, as was the case with the
helper). As a result, I changed the argument type of the sock_destory
kfunc to `sock_common`.
====================
Signed-off-by: Martin KaFai Lau <[email protected]>
-rw-r--r-- | include/linux/btf.h | 18 | ||||
-rw-r--r-- | include/net/udp.h | 1 | ||||
-rw-r--r-- | kernel/bpf/btf.c | 65 | ||||
-rw-r--r-- | kernel/bpf/verifier.c | 7 | ||||
-rw-r--r-- | net/core/filter.c | 63 | ||||
-rw-r--r-- | net/ipv4/tcp.c | 9 | ||||
-rw-r--r-- | net/ipv4/tcp_ipv4.c | 7 | ||||
-rw-r--r-- | net/ipv4/udp.c | 291 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/network_helpers.c | 23 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/network_helpers.h | 1 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/prog_tests/sock_destroy.c | 221 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/sock_destroy_prog.c | 145 | ||||
-rw-r--r-- | tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c | 22 |
13 files changed, 794 insertions, 79 deletions
diff --git a/include/linux/btf.h b/include/linux/btf.h index 508199e38415..cac9f304e27a 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -98,10 +98,14 @@ struct btf_type; union bpf_attr; struct btf_show; struct btf_id_set; +struct bpf_prog; + +typedef int (*btf_kfunc_filter_t)(const struct bpf_prog *prog, u32 kfunc_id); struct btf_kfunc_id_set { struct module *owner; struct btf_id_set8 *set; + btf_kfunc_filter_t filter; }; struct btf_id_dtor_kfunc { @@ -479,7 +483,6 @@ static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id) return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func); } -struct bpf_prog; struct bpf_verifier_log; #ifdef CONFIG_BPF_SYSCALL @@ -487,10 +490,10 @@ const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id); const char *btf_name_by_offset(const struct btf *btf, u32 offset); struct btf *btf_parse_vmlinux(void); struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog); -u32 *btf_kfunc_id_set_contains(const struct btf *btf, - enum bpf_prog_type prog_type, - u32 kfunc_btf_id); -u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id); +u32 *btf_kfunc_id_set_contains(const struct btf *btf, u32 kfunc_btf_id, + const struct bpf_prog *prog); +u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id, + const struct bpf_prog *prog); int register_btf_kfunc_id_set(enum bpf_prog_type prog_type, const struct btf_kfunc_id_set *s); int register_btf_fmodret_id_set(const struct btf_kfunc_id_set *kset); @@ -517,8 +520,9 @@ static inline const char *btf_name_by_offset(const struct btf *btf, return NULL; } static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf, - enum bpf_prog_type prog_type, - u32 kfunc_btf_id) + u32 kfunc_btf_id, + struct bpf_prog *prog) + { return NULL; } diff --git a/include/net/udp.h b/include/net/udp.h index de4b528522bb..5cad44318d71 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -437,7 +437,6 @@ struct udp_seq_afinfo { struct udp_iter_state { struct seq_net_private p; int bucket; - struct udp_seq_afinfo *bpf_seq_afinfo; }; void *udp_seq_start(struct seq_file *seq, loff_t *pos); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 6b682b8e4b50..947f0b83bfad 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -222,10 +222,17 @@ enum btf_kfunc_hook { enum { BTF_KFUNC_SET_MAX_CNT = 256, BTF_DTOR_KFUNC_MAX_CNT = 256, + BTF_KFUNC_FILTER_MAX_CNT = 16, +}; + +struct btf_kfunc_hook_filter { + btf_kfunc_filter_t filters[BTF_KFUNC_FILTER_MAX_CNT]; + u32 nr_filters; }; struct btf_kfunc_set_tab { struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX]; + struct btf_kfunc_hook_filter hook_filters[BTF_KFUNC_HOOK_MAX]; }; struct btf_id_dtor_kfunc_tab { @@ -7669,9 +7676,12 @@ static int btf_check_kfunc_protos(struct btf *btf, u32 func_id, u32 func_flags) /* Kernel Function (kfunc) BTF ID set registration API */ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook, - struct btf_id_set8 *add_set) + const struct btf_kfunc_id_set *kset) { + struct btf_kfunc_hook_filter *hook_filter; + struct btf_id_set8 *add_set = kset->set; bool vmlinux_set = !btf_is_module(btf); + bool add_filter = !!kset->filter; struct btf_kfunc_set_tab *tab; struct btf_id_set8 *set; u32 set_cnt; @@ -7686,6 +7696,24 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook, return 0; tab = btf->kfunc_set_tab; + + if (tab && add_filter) { + u32 i; + + hook_filter = &tab->hook_filters[hook]; + for (i = 0; i < hook_filter->nr_filters; i++) { + if (hook_filter->filters[i] == kset->filter) { + add_filter = false; + break; + } + } + + if (add_filter && hook_filter->nr_filters == BTF_KFUNC_FILTER_MAX_CNT) { + ret = -E2BIG; + goto end; + } + } + if (!tab) { tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN); if (!tab) @@ -7708,7 +7736,7 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook, */ if (!vmlinux_set) { tab->sets[hook] = add_set; - return 0; + goto do_add_filter; } /* In case of vmlinux sets, there may be more than one set being @@ -7750,6 +7778,11 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook, sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL); +do_add_filter: + if (add_filter) { + hook_filter = &tab->hook_filters[hook]; + hook_filter->filters[hook_filter->nr_filters++] = kset->filter; + } return 0; end: btf_free_kfunc_set_tab(btf); @@ -7758,15 +7791,22 @@ end: static u32 *__btf_kfunc_id_set_contains(const struct btf *btf, enum btf_kfunc_hook hook, - u32 kfunc_btf_id) + u32 kfunc_btf_id, + const struct bpf_prog *prog) { + struct btf_kfunc_hook_filter *hook_filter; struct btf_id_set8 *set; - u32 *id; + u32 *id, i; if (hook >= BTF_KFUNC_HOOK_MAX) return NULL; if (!btf->kfunc_set_tab) return NULL; + hook_filter = &btf->kfunc_set_tab->hook_filters[hook]; + for (i = 0; i < hook_filter->nr_filters; i++) { + if (hook_filter->filters[i](prog, kfunc_btf_id)) + return NULL; + } set = btf->kfunc_set_tab->sets[hook]; if (!set) return NULL; @@ -7821,23 +7861,25 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) * protection for looking up a well-formed btf->kfunc_set_tab. */ u32 *btf_kfunc_id_set_contains(const struct btf *btf, - enum bpf_prog_type prog_type, - u32 kfunc_btf_id) + u32 kfunc_btf_id, + const struct bpf_prog *prog) { + enum bpf_prog_type prog_type = resolve_prog_type(prog); enum btf_kfunc_hook hook; u32 *kfunc_flags; - kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id); + kfunc_flags = __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_COMMON, kfunc_btf_id, prog); if (kfunc_flags) return kfunc_flags; hook = bpf_prog_type_to_kfunc_hook(prog_type); - return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id); + return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id, prog); } -u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id) +u32 *btf_kfunc_is_modify_return(const struct btf *btf, u32 kfunc_btf_id, + const struct bpf_prog *prog) { - return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id); + return __btf_kfunc_id_set_contains(btf, BTF_KFUNC_HOOK_FMODRET, kfunc_btf_id, prog); } static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, @@ -7868,7 +7910,8 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, goto err_out; } - ret = btf_populate_kfunc_set(btf, hook, kset->set); + ret = btf_populate_kfunc_set(btf, hook, kset); + err_out: btf_put(btf); return ret; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f597491259ab..af70dad655ab 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10939,7 +10939,7 @@ static int fetch_kfunc_meta(struct bpf_verifier_env *env, *kfunc_name = func_name; func_proto = btf_type_by_id(desc_btf, func->type); - kfunc_flags = btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), func_id); + kfunc_flags = btf_kfunc_id_set_contains(desc_btf, func_id, env->prog); if (!kfunc_flags) { return -EACCES; } @@ -19010,7 +19010,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, * in the fmodret id set with the KF_SLEEPABLE flag. */ else { - u32 *flags = btf_kfunc_is_modify_return(btf, btf_id); + u32 *flags = btf_kfunc_is_modify_return(btf, btf_id, + prog); if (flags && (*flags & KF_SLEEPABLE)) ret = 0; @@ -19038,7 +19039,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, return -EINVAL; } ret = -EINVAL; - if (btf_kfunc_is_modify_return(btf, btf_id) || + if (btf_kfunc_is_modify_return(btf, btf_id, prog) || !check_attach_modify_return(addr, tname)) ret = 0; if (ret) { diff --git a/net/core/filter.c b/net/core/filter.c index 451b0ec7f242..968139f4a1ac 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -11723,3 +11723,66 @@ static int __init bpf_kfunc_init(void) return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); } late_initcall(bpf_kfunc_init); + +/* Disables missing prototype warnings */ +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes", + "Global functions as their definitions will be in vmlinux BTF"); + +/* bpf_sock_destroy: Destroy the given socket with ECONNABORTED error code. + * + * The function expects a non-NULL pointer to a socket, and invokes the + * protocol specific socket destroy handlers. + * + * The helper can only be called from BPF contexts that have acquired the socket + * locks. + * + * Parameters: + * @sock: Pointer to socket to be destroyed + * + * Return: + * On error, may return EPROTONOSUPPORT, EINVAL. + * EPROTONOSUPPORT if protocol specific destroy handler is not supported. + * 0 otherwise + */ +__bpf_kfunc int bpf_sock_destroy(struct sock_common *sock) +{ + struct sock *sk = (struct sock *)sock; + + /* The locking semantics that allow for synchronous execution of the + * destroy handlers are only supported for TCP and UDP. + * Supporting protocols will need to acquire sock lock in the BPF context + * prior to invoking this kfunc. + */ + if (!sk->sk_prot->diag_destroy || (sk->sk_protocol != IPPROTO_TCP && + sk->sk_protocol != IPPROTO_UDP)) + return -EOPNOTSUPP; + + return sk->sk_prot->diag_destroy(sk, ECONNABORTED); +} + +__diag_pop() + +BTF_SET8_START(bpf_sk_iter_kfunc_ids) +BTF_ID_FLAGS(func, bpf_sock_destroy, KF_TRUSTED_ARGS) +BTF_SET8_END(bpf_sk_iter_kfunc_ids) + +static int tracing_iter_filter(const struct bpf_prog *prog, u32 kfunc_id) +{ + if (btf_id_set8_contains(&bpf_sk_iter_kfunc_ids, kfunc_id) && + prog->expected_attach_type != BPF_TRACE_ITER) + return -EACCES; + return 0; +} + +static const struct btf_kfunc_id_set bpf_sk_iter_kfunc_set = { + .owner = THIS_MODULE, + .set = &bpf_sk_iter_kfunc_ids, + .filter = tracing_iter_filter, +}; + +static int init_subsystem(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_sk_iter_kfunc_set); +} +late_initcall(init_subsystem); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 4d6392c16b7a..87a04c3d9425 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4682,8 +4682,10 @@ int tcp_abort(struct sock *sk, int err) return 0; } - /* Don't race with userspace socket closes such as tcp_close. */ - lock_sock(sk); + /* BPF context ensures sock locking. */ + if (!has_current_bpf_ctx()) + /* Don't race with userspace socket closes such as tcp_close. */ + lock_sock(sk); if (sk->sk_state == TCP_LISTEN) { tcp_set_state(sk, TCP_CLOSE); @@ -4707,7 +4709,8 @@ int tcp_abort(struct sock *sk, int err) bh_unlock_sock(sk); local_bh_enable(); tcp_write_queue_purge(sk); - release_sock(sk); + if (!has_current_bpf_ctx()) + release_sock(sk); return 0; } EXPORT_SYMBOL_GPL(tcp_abort); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index db24ed8f8509..6c2a5f1c63c4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2962,7 +2962,6 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) struct bpf_iter_meta meta; struct bpf_prog *prog; struct sock *sk = v; - bool slow; uid_t uid; int ret; @@ -2970,7 +2969,7 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) return 0; if (sk_fullsock(sk)) - slow = lock_sock_fast(sk); + lock_sock(sk); if (unlikely(sk_unhashed(sk))) { ret = SEQ_SKIP; @@ -2994,7 +2993,7 @@ static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) unlock: if (sk_fullsock(sk)) - unlock_sock_fast(sk, slow); + release_sock(sk); return ret; } @@ -3356,7 +3355,7 @@ static struct bpf_iter_reg tcp_reg_info = { .ctx_arg_info_size = 1, .ctx_arg_info = { { offsetof(struct bpf_iter__tcp, sk_common), - PTR_TO_BTF_ID_OR_NULL }, + PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, }, .get_func_proto = bpf_iter_tcp_get_func_proto, .seq_info = &tcp_seq_info, diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index aa32afd871ee..6893fb867529 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2930,7 +2930,8 @@ EXPORT_SYMBOL(udp_poll); int udp_abort(struct sock *sk, int err) { - lock_sock(sk); + if (!has_current_bpf_ctx()) + lock_sock(sk); /* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing * with close() @@ -2943,7 +2944,8 @@ int udp_abort(struct sock *sk, int err) __udp_disconnect(sk, 0); out: - release_sock(sk); + if (!has_current_bpf_ctx()) + release_sock(sk); return 0; } @@ -2988,9 +2990,30 @@ EXPORT_SYMBOL(udp_prot); /* ------------------------------------------------------------------------ */ #ifdef CONFIG_PROC_FS -static struct udp_table *udp_get_table_afinfo(struct udp_seq_afinfo *afinfo, - struct net *net) +static unsigned short seq_file_family(const struct seq_file *seq); +static bool seq_sk_match(struct seq_file *seq, const struct sock *sk) +{ + unsigned short family = seq_file_family(seq); + + /* AF_UNSPEC is used as a match all */ + return ((family == AF_UNSPEC || family == sk->sk_family) && + net_eq(sock_net(sk), seq_file_net(seq))); +} + +#ifdef CONFIG_BPF_SYSCALL +static const struct seq_operations bpf_iter_udp_seq_ops; +#endif +static struct udp_table *udp_get_table_seq(struct seq_file *seq, + struct net *net) { + const struct udp_seq_afinfo *afinfo; + +#ifdef CONFIG_BPF_SYSCALL + if (seq->op == &bpf_iter_udp_seq_ops) + return net->ipv4.udp_table; +#endif + + afinfo = pde_data(file_inode(seq->file)); return afinfo->udp_table ? : net->ipv4.udp_table; } @@ -2998,16 +3021,10 @@ static struct sock *udp_get_first(struct seq_file *seq, int start) { struct udp_iter_state *state = seq->private; struct net *net = seq_file_net(seq); - struct udp_seq_afinfo *afinfo; struct udp_table *udptable; struct sock *sk; - if (state->bpf_seq_afinfo) - afinfo = state->bpf_seq_afinfo; - else - afinfo = pde_data(file_inode(seq->file)); - - udptable = udp_get_table_afinfo(afinfo, net); + udptable = udp_get_table_seq(seq, net); for (state->bucket = start; state->bucket <= udptable->mask; ++state->bucket) { @@ -3018,10 +3035,7 @@ static struct sock *udp_get_first(struct seq_file *seq, int start) spin_lock_bh(&hslot->lock); sk_for_each(sk, &hslot->head) { - if (!net_eq(sock_net(sk), net)) - continue; - if (afinfo->family == AF_UNSPEC || - sk->sk_family == afinfo->family) + if (seq_sk_match(seq, sk)) goto found; } spin_unlock_bh(&hslot->lock); @@ -3035,22 +3049,14 @@ static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk) { struct udp_iter_state *state = seq->private; struct net *net = seq_file_net(seq); - struct udp_seq_afinfo *afinfo; struct udp_table *udptable; - if (state->bpf_seq_afinfo) - afinfo = state->bpf_seq_afinfo; - else - afinfo = pde_data(file_inode(seq->file)); - do { sk = sk_next(sk); - } while (sk && (!net_eq(sock_net(sk), net) || - (afinfo->family != AF_UNSPEC && - sk->sk_family != afinfo->family))); + } while (sk && !seq_sk_match(seq, sk)); if (!sk) { - udptable = udp_get_table_afinfo(afinfo, net); + udptable = udp_get_table_seq(seq, net); if (state->bucket <= udptable->mask) spin_unlock_bh(&udptable->hash[state->bucket].lock); @@ -3096,15 +3102,9 @@ EXPORT_SYMBOL(udp_seq_next); void udp_seq_stop(struct seq_file *seq, void *v) { struct udp_iter_state *state = seq->private; - struct udp_seq_afinfo *afinfo; struct udp_table *udptable; - if (state->bpf_seq_afinfo) - afinfo = state->bpf_seq_afinfo; - else - afinfo = pde_data(file_inode(seq->file)); - - udptable = udp_get_table_afinfo(afinfo, seq_file_net(seq)); + udptable = udp_get_table_seq(seq, seq_file_net(seq)); if (state->bucket <= udptable->mask) spin_unlock_bh(&udptable->hash[state->bucket].lock); @@ -3157,6 +3157,143 @@ struct bpf_iter__udp { int bucket __aligned(8); }; +struct bpf_udp_iter_state { + struct udp_iter_state state; + unsigned int cur_sk; + unsigned int end_sk; + unsigned int max_sk; + int offset; + struct sock **batch; + bool st_bucket_done; +}; + +static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter, + unsigned int new_batch_sz); +static struct sock *bpf_iter_udp_batch(struct seq_file *seq) +{ + struct bpf_udp_iter_state *iter = seq->private; + struct udp_iter_state *state = &iter->state; + struct net *net = seq_file_net(seq); + struct udp_table *udptable; + unsigned int batch_sks = 0; + bool resized = false; + struct sock *sk; + + /* The current batch is done, so advance the bucket. */ + if (iter->st_bucket_done) { + state->bucket++; + iter->offset = 0; + } + + udptable = udp_get_table_seq(seq, net); + +again: + /* New batch for the next bucket. + * Iterate over the hash table to find a bucket with sockets matching + * the iterator attributes, and return the first matching socket from + * the bucket. The remaining matched sockets from the bucket are batched + * before releasing the bucket lock. This allows BPF programs that are + * called in seq_show to acquire the bucket lock if needed. + */ + iter->cur_sk = 0; + iter->end_sk = 0; + iter->st_bucket_done = false; + batch_sks = 0; + + for (; state->bucket <= udptable->mask; state->bucket++) { + struct udp_hslot *hslot2 = &udptable->hash2[state->bucket]; + + if (hlist_empty(&hslot2->head)) { + iter->offset = 0; + continue; + } + + spin_lock_bh(&hslot2->lock); + udp_portaddr_for_each_entry(sk, &hslot2->head) { + if (seq_sk_match(seq, sk)) { + /* Resume from the last iterated socket at the + * offset in the bucket before iterator was stopped. + */ + if (iter->offset) { + --iter->offset; + continue; + } + if (iter->end_sk < iter->max_sk) { + sock_hold(sk); + iter->batch[iter->end_sk++] = sk; + } + batch_sks++; + } + } + spin_unlock_bh(&hslot2->lock); + + if (iter->end_sk) + break; + + /* Reset the current bucket's offset before moving to the next bucket. */ + iter->offset = 0; + } + + /* All done: no batch made. */ + if (!iter->end_sk) + return NULL; + + if (iter->end_sk == batch_sks) { + /* Batching is done for the current bucket; return the first + * socket to be iterated from the batch. + */ + iter->st_bucket_done = true; + goto done; + } + if (!resized && !bpf_iter_udp_realloc_batch(iter, batch_sks * 3 / 2)) { + resized = true; + /* After allocating a larger batch, retry one more time to grab + * the whole bucket. + */ + state->bucket--; + goto again; + } +done: + return iter->batch[0]; +} + +static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct bpf_udp_iter_state *iter = seq->private; + struct sock *sk; + + /* Whenever seq_next() is called, the iter->cur_sk is + * done with seq_show(), so unref the iter->cur_sk. + */ + if (iter->cur_sk < iter->end_sk) { + sock_put(iter->batch[iter->cur_sk++]); + ++iter->offset; + } + + /* After updating iter->cur_sk, check if there are more sockets + * available in the current bucket batch. + */ + if (iter->cur_sk < iter->end_sk) + sk = iter->batch[iter->cur_sk]; + else + /* Prepare a new batch. */ + sk = bpf_iter_udp_batch(seq); + + ++*pos; + return sk; +} + +static void *bpf_iter_udp_seq_start(struct seq_file *seq, loff_t *pos) +{ + /* bpf iter does not support lseek, so it always + * continue from where it was stop()-ped. + */ + if (*pos) + return bpf_iter_udp_batch(seq); + + return SEQ_START_TOKEN; +} + static int udp_prog_seq_show(struct bpf_prog *prog, struct bpf_iter_meta *meta, struct udp_sock *udp_sk, uid_t uid, int bucket) { @@ -3177,18 +3314,37 @@ static int bpf_iter_udp_seq_show(struct seq_file *seq, void *v) struct bpf_prog *prog; struct sock *sk = v; uid_t uid; + int ret; if (v == SEQ_START_TOKEN) return 0; + lock_sock(sk); + + if (unlikely(sk_unhashed(sk))) { + ret = SEQ_SKIP; + goto unlock; + } + uid = from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)); meta.seq = seq; prog = bpf_iter_get_info(&meta, false); - return udp_prog_seq_show(prog, &meta, v, uid, state->bucket); + ret = udp_prog_seq_show(prog, &meta, v, uid, state->bucket); + +unlock: + release_sock(sk); + return ret; +} + +static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter) +{ + while (iter->cur_sk < iter->end_sk) + sock_put(iter->batch[iter->cur_sk++]); } static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v) { + struct bpf_udp_iter_state *iter = seq->private; struct bpf_iter_meta meta; struct bpf_prog *prog; @@ -3199,17 +3355,35 @@ static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v) (void)udp_prog_seq_show(prog, &meta, v, 0, 0); } - udp_seq_stop(seq, v); + if (iter->cur_sk < iter->end_sk) { + bpf_iter_udp_put_batch(iter); + iter->st_bucket_done = false; + } } static const struct seq_operations bpf_iter_udp_seq_ops = { - .start = udp_seq_start, - .next = udp_seq_next, + .start = bpf_iter_udp_seq_start, + .next = bpf_iter_udp_seq_next, .stop = bpf_iter_udp_seq_stop, .show = bpf_iter_udp_seq_show, }; #endif +static unsigned short seq_file_family(const struct seq_file *seq) +{ + const struct udp_seq_afinfo *afinfo; + +#ifdef CONFIG_BPF_SYSCALL + /* BPF iterator: bpf programs to filter sockets. */ + if (seq->op == &bpf_iter_udp_seq_ops) + return AF_UNSPEC; +#endif + + /* Proc fs iterator */ + afinfo = pde_data(file_inode(seq->file)); + return afinfo->family; +} + const struct seq_operations udp_seq_ops = { .start = udp_seq_start, .next = udp_seq_next, @@ -3418,38 +3592,55 @@ static struct pernet_operations __net_initdata udp_sysctl_ops = { DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta, struct udp_sock *udp_sk, uid_t uid, int bucket) -static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux) +static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter, + unsigned int new_batch_sz) { - struct udp_iter_state *st = priv_data; - struct udp_seq_afinfo *afinfo; - int ret; + struct sock **new_batch; - afinfo = kmalloc(sizeof(*afinfo), GFP_USER | __GFP_NOWARN); - if (!afinfo) + new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch), + GFP_USER | __GFP_NOWARN); + if (!new_batch) return -ENOMEM; - afinfo->family = AF_UNSPEC; - afinfo->udp_table = NULL; - st->bpf_seq_afinfo = afinfo; + bpf_iter_udp_put_batch(iter); + kvfree(iter->batch); + iter->batch = new_batch; + iter->max_sk = new_batch_sz; + + return 0; +} + +#define INIT_BATCH_SZ 16 + +static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux) +{ + struct bpf_udp_iter_state *iter = priv_data; + int ret; + ret = bpf_iter_init_seq_net(priv_data, aux); if (ret) - kfree(afinfo); + return ret; + + ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ); + if (ret) + bpf_iter_fini_seq_net(priv_data); + return ret; } static void bpf_iter_fini_udp(void *priv_data) { - struct udp_iter_state *st = priv_data; + struct bpf_udp_iter_state *iter = priv_data; - kfree(st->bpf_seq_afinfo); bpf_iter_fini_seq_net(priv_data); + kvfree(iter->batch); } static const struct bpf_iter_seq_info udp_seq_info = { .seq_ops = &bpf_iter_udp_seq_ops, .init_seq_private = bpf_iter_init_udp, .fini_seq_private = bpf_iter_fini_udp, - .seq_priv_size = sizeof(struct udp_iter_state), + .seq_priv_size = sizeof(struct bpf_udp_iter_state), }; static struct bpf_iter_reg udp_reg_info = { @@ -3457,7 +3648,7 @@ static struct bpf_iter_reg udp_reg_info = { .ctx_arg_info_size = 1, .ctx_arg_info = { { offsetof(struct bpf_iter__udp, udp_sk), - PTR_TO_BTF_ID_OR_NULL }, + PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED }, }, .seq_info = &udp_seq_info, }; diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 596caa176582..a105c0cd008a 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -427,3 +427,26 @@ void close_netns(struct nstoken *token) close(token->orig_netns_fd); free(token); } + +int get_socket_local_port(int sock_fd) +{ + struct sockaddr_storage addr; + socklen_t addrlen = sizeof(addr); + int err; + + err = getsockname(sock_fd, (struct sockaddr *)&addr, &addrlen); + if (err < 0) + return err; + + if (addr.ss_family == AF_INET) { + struct sockaddr_in *sin = (struct sockaddr_in *)&addr; + + return sin->sin_port; + } else if (addr.ss_family == AF_INET6) { + struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&addr; + + return sin->sin6_port; + } + + return -1; +} diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h index f882c691b790..694185644da6 100644 --- a/tools/testing/selftests/bpf/network_helpers.h +++ b/tools/testing/selftests/bpf/network_helpers.h @@ -56,6 +56,7 @@ int fastopen_connect(int server_fd, const char *data, unsigned int data_len, int make_sockaddr(int family, const char *addr_str, __u16 port, struct sockaddr_storage *addr, socklen_t *len); char *ping_command(int family); +int get_socket_local_port(int sock_fd); struct nstoken; /** diff --git a/tools/testing/selftests/bpf/prog_tests/sock_destroy.c b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c new file mode 100644 index 000000000000..b0583309a94e --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> +#include <bpf/bpf_endian.h> + +#include "sock_destroy_prog.skel.h" +#include "sock_destroy_prog_fail.skel.h" +#include "network_helpers.h" + +#define TEST_NS "sock_destroy_netns" + +static void start_iter_sockets(struct bpf_program *prog) +{ + struct bpf_link *link; + char buf[50] = {}; + int iter_fd, len; + + link = bpf_program__attach_iter(prog, NULL); + if (!ASSERT_OK_PTR(link, "attach_iter")) + return; + + iter_fd = bpf_iter_create(bpf_link__fd(link)); + if (!ASSERT_GE(iter_fd, 0, "create_iter")) + goto free_link; + + while ((len = read(iter_fd, buf, sizeof(buf))) > 0) + ; + ASSERT_GE(len, 0, "read"); + + close(iter_fd); + +free_link: + bpf_link__destroy(link); +} + +static void test_tcp_client(struct sock_destroy_prog *skel) +{ + int serv = -1, clien = -1, accept_serv = -1, n; + + serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0); + if (!ASSERT_GE(serv, 0, "start_server")) + goto cleanup; + + clien = connect_to_fd(serv, 0); + if (!ASSERT_GE(clien, 0, "connect_to_fd")) + goto cleanup; + + accept_serv = accept(serv, NULL, NULL); + if (!ASSERT_GE(accept_serv, 0, "serv accept")) + goto cleanup; + + n = send(clien, "t", 1, 0); + if (!ASSERT_EQ(n, 1, "client send")) + goto cleanup; + + /* Run iterator program that destroys connected client sockets. */ + start_iter_sockets(skel->progs.iter_tcp6_client); + + n = send(clien, "t", 1, 0); + if (!ASSERT_LT(n, 0, "client_send on destroyed socket")) + goto cleanup; + ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket"); + +cleanup: + if (clien != -1) + close(clien); + if (accept_serv != -1) + close(accept_serv); + if (serv != -1) + close(serv); +} + +static void test_tcp_server(struct sock_destroy_prog *skel) +{ + int serv = -1, clien = -1, accept_serv = -1, n, serv_port; + + serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0); + if (!ASSERT_GE(serv, 0, "start_server")) + goto cleanup; + serv_port = get_socket_local_port(serv); + if (!ASSERT_GE(serv_port, 0, "get_sock_local_port")) + goto cleanup; + skel->bss->serv_port = (__be16) serv_port; + + clien = connect_to_fd(serv, 0); + if (!ASSERT_GE(clien, 0, "connect_to_fd")) + goto cleanup; + + accept_serv = accept(serv, NULL, NULL); + if (!ASSERT_GE(accept_serv, 0, "serv accept")) + goto cleanup; + + n = send(clien, "t", 1, 0); + if (!ASSERT_EQ(n, 1, "client send")) + goto cleanup; + + /* Run iterator program that destroys server sockets. */ + start_iter_sockets(skel->progs.iter_tcp6_server); + + n = send(clien, "t", 1, 0); + if (!ASSERT_LT(n, 0, "client_send on destroyed socket")) + goto cleanup; + ASSERT_EQ(errno, ECONNRESET, "error code on destroyed socket"); + +cleanup: + if (clien != -1) + close(clien); + if (accept_serv != -1) + close(accept_serv); + if (serv != -1) + close(serv); +} + +static void test_udp_client(struct sock_destroy_prog *skel) +{ + int serv = -1, clien = -1, n = 0; + + serv = start_server(AF_INET6, SOCK_DGRAM, NULL, 0, 0); + if (!ASSERT_GE(serv, 0, "start_server")) + goto cleanup; + + clien = connect_to_fd(serv, 0); + if (!ASSERT_GE(clien, 0, "connect_to_fd")) + goto cleanup; + + n = send(clien, "t", 1, 0); + if (!ASSERT_EQ(n, 1, "client send")) + goto cleanup; + + /* Run iterator program that destroys sockets. */ + start_iter_sockets(skel->progs.iter_udp6_client); + + n = send(clien, "t", 1, 0); + if (!ASSERT_LT(n, 0, "client_send on destroyed socket")) + goto cleanup; + /* UDP sockets have an overriding error code after they are disconnected, + * so we don't check for ECONNABORTED error code. + */ + +cleanup: + if (clien != -1) + close(clien); + if (serv != -1) + close(serv); +} + +static void test_udp_server(struct sock_destroy_prog *skel) +{ + int *listen_fds = NULL, n, i, serv_port; + unsigned int num_listens = 5; + char buf[1]; + + /* Start reuseport servers. */ + listen_fds = start_reuseport_server(AF_INET6, SOCK_DGRAM, + "::1", 0, 0, num_listens); + if (!ASSERT_OK_PTR(listen_fds, "start_reuseport_server")) + goto cleanup; + serv_port = get_socket_local_port(listen_fds[0]); + if (!ASSERT_GE(serv_port, 0, "get_sock_local_port")) + goto cleanup; + skel->bss->serv_port = (__be16) serv_port; + + /* Run iterator program that destroys server sockets. */ + start_iter_sockets(skel->progs.iter_udp6_server); + + for (i = 0; i < num_listens; ++i) { + n = read(listen_fds[i], buf, sizeof(buf)); + if (!ASSERT_EQ(n, -1, "read") || + !ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket")) + break; + } + ASSERT_EQ(i, num_listens, "server socket"); + +cleanup: + free_fds(listen_fds, num_listens); +} + +void test_sock_destroy(void) +{ + struct sock_destroy_prog *skel; + struct nstoken *nstoken = NULL; + int cgroup_fd; + + skel = sock_destroy_prog__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + cgroup_fd = test__join_cgroup("/sock_destroy"); + if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup")) + goto cleanup; + + skel->links.sock_connect = bpf_program__attach_cgroup( + skel->progs.sock_connect, cgroup_fd); + if (!ASSERT_OK_PTR(skel->links.sock_connect, "prog_attach")) + goto cleanup; + + SYS(cleanup, "ip netns add %s", TEST_NS); + SYS(cleanup, "ip -net %s link set dev lo up", TEST_NS); + + nstoken = open_netns(TEST_NS); + if (!ASSERT_OK_PTR(nstoken, "open_netns")) + goto cleanup; + + if (test__start_subtest("tcp_client")) + test_tcp_client(skel); + if (test__start_subtest("tcp_server")) + test_tcp_server(skel); + if (test__start_subtest("udp_client")) + test_udp_client(skel); + if (test__start_subtest("udp_server")) + test_udp_server(skel); + + RUN_TESTS(sock_destroy_prog_fail); + +cleanup: + if (nstoken) + close_netns(nstoken); + SYS_NOFAIL("ip netns del " TEST_NS " &> /dev/null"); + if (cgroup_fd >= 0) + close(cgroup_fd); + sock_destroy_prog__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/sock_destroy_prog.c b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c new file mode 100644 index 000000000000..9e0bf7a54cec --- /dev/null +++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_endian.h> + +#include "bpf_tracing_net.h" + +__be16 serv_port = 0; + +int bpf_sock_destroy(struct sock_common *sk) __ksym; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u64); +} tcp_conn_sockets SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u64); +} udp_conn_sockets SEC(".maps"); + +SEC("cgroup/connect6") +int sock_connect(struct bpf_sock_addr *ctx) +{ + __u64 sock_cookie = 0; + int key = 0; + __u32 keyc = 0; + + if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6) + return 1; + + sock_cookie = bpf_get_socket_cookie(ctx); + if (ctx->protocol == IPPROTO_TCP) + bpf_map_update_elem(&tcp_conn_sockets, &key, &sock_cookie, 0); + else if (ctx->protocol == IPPROTO_UDP) + bpf_map_update_elem(&udp_conn_sockets, &keyc, &sock_cookie, 0); + else + return 1; + + return 1; +} + +SEC("iter/tcp") +int iter_tcp6_client(struct bpf_iter__tcp *ctx) +{ + struct sock_common *sk_common = ctx->sk_common; + __u64 sock_cookie = 0; + __u64 *val; + int key = 0; + + if (!sk_common) + return 0; + + if (sk_common->skc_family != AF_INET6) + return 0; + + sock_cookie = bpf_get_socket_cookie(sk_common); + val = bpf_map_lookup_elem(&tcp_conn_sockets, &key); + if (!val) + return 0; + /* Destroy connected client sockets. */ + if (sock_cookie == *val) + bpf_sock_destroy(sk_common); + + return 0; +} + +SEC("iter/tcp") +int iter_tcp6_server(struct bpf_iter__tcp *ctx) +{ + struct sock_common *sk_common = ctx->sk_common; + const struct inet_connection_sock *icsk; + const struct inet_sock *inet; + struct tcp6_sock *tcp_sk; + __be16 srcp; + + if (!sk_common) + return 0; + + if (sk_common->skc_family != AF_INET6) + return 0; + + tcp_sk = bpf_skc_to_tcp6_sock(sk_common); + if (!tcp_sk) + return 0; + + icsk = &tcp_sk->tcp.inet_conn; + inet = &icsk->icsk_inet; + srcp = inet->inet_sport; + + /* Destroy server sockets. */ + if (srcp == serv_port) + bpf_sock_destroy(sk_common); + + return 0; +} + + +SEC("iter/udp") +int iter_udp6_client(struct bpf_iter__udp *ctx) +{ + struct udp_sock *udp_sk = ctx->udp_sk; + struct sock *sk = (struct sock *) udp_sk; + __u64 sock_cookie = 0, *val; + int key = 0; + + if (!sk) + return 0; + + sock_cookie = bpf_get_socket_cookie(sk); + val = bpf_map_lookup_elem(&udp_conn_sockets, &key); + if (!val) + return 0; + /* Destroy connected client sockets. */ + if (sock_cookie == *val) + bpf_sock_destroy((struct sock_common *)sk); + + return 0; +} + +SEC("iter/udp") +int iter_udp6_server(struct bpf_iter__udp *ctx) +{ + struct udp_sock *udp_sk = ctx->udp_sk; + struct sock *sk = (struct sock *) udp_sk; + struct inet_sock *inet; + __be16 srcp; + + if (!sk) + return 0; + + inet = &udp_sk->inet; + srcp = inet->inet_sport; + if (srcp == serv_port) + bpf_sock_destroy((struct sock_common *)sk); + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c b/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c new file mode 100644 index 000000000000..dd6850b58e25 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog_fail.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h> + +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +int bpf_sock_destroy(struct sock_common *sk) __ksym; + +SEC("tp_btf/tcp_destroy_sock") +__failure __msg("calling kernel function bpf_sock_destroy is not allowed") +int BPF_PROG(trace_tcp_destroy_sock, struct sock *sk) +{ + /* should not load */ + bpf_sock_destroy((struct sock_common *)sk); + + return 0; +} + |