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bpf: introduce verifier internal test flag 

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

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
alistair/sunxi64-5.4-dsi
Alexei Starovoitov 2019-08-22 22:52:12 -07:00 committed by Daniel Borkmann
parent 0bb52b0dfc
commit 10d274e880
4 changed files with 9 additions and 1 deletions
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1
include/linux/bpf_verifier.h
View File

@ -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;

3
include/uapi/linux/bpf.h
View File

@ -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:
*

1
kernel/bpf/syscall.c
View File

@ -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;

5
kernel/bpf/verifier.c
View File

@ -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;