From 10d274e880eb208ec6a76261a9f8f8155020f771 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 22 Aug 2019 22:52:12 -0700 Subject: [PATCH] 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 Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- include/linux/bpf_verifier.h | 1 + include/uapi/linux/bpf.h | 3 +++ kernel/bpf/syscall.c | 1 + kernel/bpf/verifier.c | 5 ++++- 4 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 5fe99f322b1c..26a6d58ca78c 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -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; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index b5889257cc33..5d2fb183ee2d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -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: * diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c0f62fd67c6b..ca60eafa6922 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -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; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 10c0ff93f52b..f340cfe53c6e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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;