Commit 10d274e8 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

bpf: introduce verifier internal test flag 



Introduce BPF_F_TEST_STATE_FREQ flag to stress test parentage chain
and state pruning.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 0bb52b0d

include/linux/bpf_verifier.h

+1 −0
Original line number Diff line number Diff line
@@ -355,6 +355,7 @@ struct bpf_verifier_env { 
	struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */

	int stack_size;			/* number of states to be processed */

	bool strict_alignment;		/* perform strict pointer alignment checks */

	bool test_state_freq;		/* test verifier with different pruning frequency */

	struct bpf_verifier_state *cur_state; /* current verifier state */

	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */

	struct bpf_verifier_state_list *free_list;

include/uapi/linux/bpf.h

+3 −0
Original line number Diff line number Diff line
@@ -285,6 +285,9 @@ enum bpf_attach_type { 
 */

#define BPF_F_TEST_RND_HI32	(1U << 2)



/* The verifier internal test flag. Behavior is undefined */

#define BPF_F_TEST_STATE_FREQ	(1U << 3)



/* When BPF ldimm64's insn[0].src_reg != 0 then this can have

 * two extensions:

 *

kernel/bpf/syscall.c

+1 −0
Original line number Diff line number Diff line
@@ -1629,6 +1629,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) 


	if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT |

				 BPF_F_ANY_ALIGNMENT |

				 BPF_F_TEST_STATE_FREQ |

				 BPF_F_TEST_RND_HI32))

		return -EINVAL;

kernel/bpf/verifier.c

+4 −1
Original line number Diff line number Diff line
@@ -7222,7 +7222,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) 
	struct bpf_verifier_state_list *sl, **pprev;

	struct bpf_verifier_state *cur = env->cur_state, *new;

	int i, j, err, states_cnt = 0;

	bool add_new_state = false;

	bool add_new_state = env->test_state_freq ? true : false;



	cur->last_insn_idx = env->prev_insn_idx;

	if (!env->insn_aux_data[insn_idx].prune_point)
@@ -9262,6 +9262,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, 


	env->allow_ptr_leaks = is_priv;



	if (is_priv)

		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;



	ret = replace_map_fd_with_map_ptr(env);

	if (ret < 0)

		goto skip_full_check;