From: Alexei Starovoitov <ast@kernel.org>
Date: Thu, 22 Aug 2019 22:52:12 -0700
Subject: bpf: introduce verifier internal test flag
Patch-mainline: v5.4-rc1
Git-commit: 10d274e880eb208ec6a76261a9f8f8155020f771
References: bsc#1154353
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
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(-)
--- 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;
--- 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:
*
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1629,6 +1629,7 @@ static int bpf_prog_load(union bpf_attr
if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT |
BPF_F_ANY_ALIGNMENT |
+ BPF_F_TEST_STATE_FREQ |
BPF_F_TEST_RND_HI32))
return -EINVAL;
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7228,7 +7228,7 @@ static int is_state_visited(struct bpf_v
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)
@@ -9268,6 +9268,9 @@ int bpf_check(struct bpf_prog **prog, un
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;