提交 8726679a 编写于 作者: A Alexei Starovoitov 提交者: David S. Miller

bpf: teach verifier to track stack depth

teach verifier to track bpf program stack depth
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 f696b8f4
......@@ -171,6 +171,7 @@ struct bpf_prog_aux {
atomic_t refcnt;
u32 used_map_cnt;
u32 max_ctx_offset;
u32 stack_depth;
struct latch_tree_node ksym_tnode;
struct list_head ksym_lnode;
const struct bpf_verifier_ops *ops;
......
......@@ -926,6 +926,10 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off,
verbose("invalid stack off=%d size=%d\n", off, size);
return -EACCES;
}
if (env->prog->aux->stack_depth < -off)
env->prog->aux->stack_depth = -off;
if (t == BPF_WRITE) {
if (!env->allow_ptr_leaks &&
state->stack_slot_type[MAX_BPF_STACK + off] == STACK_SPILL &&
......@@ -1032,6 +1036,9 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
return -EACCES;
}
if (env->prog->aux->stack_depth < -off)
env->prog->aux->stack_depth = -off;
if (meta && meta->raw_mode) {
meta->access_size = access_size;
meta->regno = regno;
......@@ -3167,7 +3174,8 @@ static int do_check(struct bpf_verifier_env *env)
insn_idx++;
}
verbose("processed %d insns\n", insn_processed);
verbose("processed %d insns, stack depth %d\n",
insn_processed, env->prog->aux->stack_depth);
return 0;
}
......
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