[PATCH v2 bpf-next 1/3] bpf: bump jmp sequence limit
From: Alexei Starovoitov <ast@kernel.org>
Date: 2019-05-22 03:14:30
Also in:
bpf
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
The limit of 1024 subsequent jumps was causing otherwise valid programs to be rejected. Bump it to 8192 and make the error more verbose. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <redacted> --- kernel/bpf/verifier.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 082f6eefb1c4..4113e829616d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c@@ -176,7 +176,7 @@ struct bpf_verifier_stack_elem { struct bpf_verifier_stack_elem *next; }; -#define BPF_COMPLEXITY_LIMIT_STACK 1024 +#define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192 #define BPF_COMPLEXITY_LIMIT_STATES 64 #define BPF_MAP_PTR_UNPRIV 1UL
@@ -782,8 +782,9 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, if (err) goto err; elem->st.speculative |= speculative; - if (env->stack_size > BPF_COMPLEXITY_LIMIT_STACK) { - verbose(env, "BPF program is too complex\n"); + if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) { + verbose(env, "The sequence of %d jumps is too complex.\n", + env->stack_size); goto err; } return &elem->st;
--
2.20.0