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Commit 4d716e10 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'pkt-access-fixes' 



Daniel Borkmann says:

====================
Several fixes to get direct packet access in order from verifier
side. Also test suite fix to run cg_skb as unpriv and an improvement
to make direct packet write less error prone in future.
====================

Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 4a6998af b09928b9

kernel/bpf/helpers.c

+0 −2
Original line number Diff line number Diff line
@@ -99,7 +99,6 @@ BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value) 
const struct bpf_func_proto bpf_map_pop_elem_proto = {

	.func		= bpf_map_pop_elem,

	.gpl_only	= false,

	.pkt_access	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_CONST_MAP_PTR,

	.arg2_type	= ARG_PTR_TO_UNINIT_MAP_VALUE,
@@ -113,7 +112,6 @@ BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value) 
const struct bpf_func_proto bpf_map_peek_elem_proto = {

	.func		= bpf_map_pop_elem,

	.gpl_only	= false,

	.pkt_access	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_CONST_MAP_PTR,

	.arg2_type	= ARG_PTR_TO_UNINIT_MAP_VALUE,

kernel/bpf/queue_stack_maps.c

+2 −0
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ static int __queue_map_get(struct bpf_map *map, void *value, bool delete) 
	raw_spin_lock_irqsave(&qs->lock, flags);



	if (queue_stack_map_is_empty(qs)) {

		memset(value, 0, qs->map.value_size);

		err = -ENOENT;

		goto out;

	}
@@ -151,6 +152,7 @@ static int __stack_map_get(struct bpf_map *map, void *value, bool delete) 
	raw_spin_lock_irqsave(&qs->lock, flags);



	if (queue_stack_map_is_empty(qs)) {

		memset(value, 0, qs->map.value_size);

		err = -ENOENT;

		goto out;

	}

kernel/bpf/verifier.c

+10 −3
Original line number Diff line number Diff line
@@ -1387,21 +1387,24 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, 
				       enum bpf_access_type t)

{

	switch (env->prog->type) {

	/* Program types only with direct read access go here! */

	case BPF_PROG_TYPE_LWT_IN:

	case BPF_PROG_TYPE_LWT_OUT:

	case BPF_PROG_TYPE_LWT_SEG6LOCAL:

	case BPF_PROG_TYPE_SK_REUSEPORT:

		/* dst_input() and dst_output() can't write for now */

	case BPF_PROG_TYPE_FLOW_DISSECTOR:

	case BPF_PROG_TYPE_CGROUP_SKB:

		if (t == BPF_WRITE)

			return false;

		/* fallthrough */



	/* Program types with direct read + write access go here! */

	case BPF_PROG_TYPE_SCHED_CLS:

	case BPF_PROG_TYPE_SCHED_ACT:

	case BPF_PROG_TYPE_XDP:

	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;
@@ -5706,7 +5709,11 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) 
	bool is_narrower_load;

	u32 target_size;



	if (ops->gen_prologue) {

	if (ops->gen_prologue || env->seen_direct_write) {

		if (!ops->gen_prologue) {

			verbose(env, "bpf verifier is misconfigured\n");

			return -EINVAL;

		}

		cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,

					env->prog);

		if (cnt >= ARRAY_SIZE(insn_buf)) {

net/core/filter.c

+17 −0
Original line number Diff line number Diff line
@@ -5496,7 +5496,13 @@ static bool cg_skb_is_valid_access(int off, int size, 
	case bpf_ctx_range(struct __sk_buff, data_meta):

	case bpf_ctx_range(struct __sk_buff, flow_keys):

		return false;

	case bpf_ctx_range(struct __sk_buff, data):

	case bpf_ctx_range(struct __sk_buff, data_end):

		if (!capable(CAP_SYS_ADMIN))

			return false;

		break;

	}



	if (type == BPF_WRITE) {

		switch (off) {

		case bpf_ctx_range(struct __sk_buff, mark):
@@ -5638,6 +5644,15 @@ static bool sock_filter_is_valid_access(int off, int size, 
					       prog->expected_attach_type);

}



static int bpf_noop_prologue(struct bpf_insn *insn_buf, bool direct_write,

			     const struct bpf_prog *prog)

{

	/* Neither direct read nor direct write requires any preliminary

	 * action.

	 */

	return 0;

}



static int bpf_unclone_prologue(struct bpf_insn *insn_buf, bool direct_write,

				const struct bpf_prog *prog, int drop_verdict)

{
@@ -7204,6 +7219,7 @@ const struct bpf_verifier_ops xdp_verifier_ops = { 
	.get_func_proto		= xdp_func_proto,

	.is_valid_access	= xdp_is_valid_access,

	.convert_ctx_access	= xdp_convert_ctx_access,

	.gen_prologue		= bpf_noop_prologue,

};



const struct bpf_prog_ops xdp_prog_ops = {
@@ -7302,6 +7318,7 @@ const struct bpf_verifier_ops sk_msg_verifier_ops = { 
	.get_func_proto		= sk_msg_func_proto,

	.is_valid_access	= sk_msg_is_valid_access,

	.convert_ctx_access	= sk_msg_convert_ctx_access,

	.gen_prologue		= bpf_noop_prologue,

};



const struct bpf_prog_ops sk_msg_prog_ops = {

tools/testing/selftests/bpf/test_verifier.c

+13 −2
Original line number Diff line number Diff line
@@ -4891,6 +4891,8 @@ static struct bpf_test tests[] = { 
			BPF_EXIT_INSN(),

		},

		.result = ACCEPT,

		.result_unpriv = REJECT,

		.errstr_unpriv = "invalid bpf_context access off=76 size=4",

		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,

	},

	{
@@ -5146,6 +5148,7 @@ static struct bpf_test tests[] = { 
		.fixup_cgroup_storage = { 1 },

		.result = REJECT,

		.errstr = "get_local_storage() doesn't support non-zero flags",

		.errstr_unpriv = "R2 leaks addr into helper function",

		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,

	},

	{
@@ -5261,6 +5264,7 @@ static struct bpf_test tests[] = { 
		.fixup_percpu_cgroup_storage = { 1 },

		.result = REJECT,

		.errstr = "get_local_storage() doesn't support non-zero flags",

		.errstr_unpriv = "R2 leaks addr into helper function",

		.prog_type = BPF_PROG_TYPE_CGROUP_SKB,

	},

	{
@@ -14050,6 +14054,13 @@ static void get_unpriv_disabled() 
	fclose(fd);

}



static bool test_as_unpriv(struct bpf_test *test)

{

	return !test->prog_type ||

	       test->prog_type == BPF_PROG_TYPE_SOCKET_FILTER ||

	       test->prog_type == BPF_PROG_TYPE_CGROUP_SKB;

}



static int do_test(bool unpriv, unsigned int from, unsigned int to)

{

	int i, passes = 0, errors = 0, skips = 0;
@@ -14060,10 +14071,10 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to) 
		/* Program types that are not supported by non-root we

		 * skip right away.

		 */

		if (!test->prog_type && unpriv_disabled) {

		if (test_as_unpriv(test) && unpriv_disabled) {

			printf("#%d/u %s SKIP\n", i, test->descr);

			skips++;

		} else if (!test->prog_type) {

		} else if (test_as_unpriv(test)) {

			if (!unpriv)

				set_admin(false);

			printf("#%d/u %s ", i, test->descr);