From: Joanne Koong joannelkoong@gmail.com
[ Upstream commit 8ab4cdcf03d0b060fbf73f76460f199bbd759ff7 ]
This patch does two things:
1. For matching against the arg type, the match should be against the base type of the arg type, since the arg type can have different bpf_type_flags set on it.
2. Uses switch casing to improve readability + efficiency.
Signed-off-by: Joanne Koong joannelkoong@gmail.com Acked-by: Hao Luo haoluo@google.com Link: https://lore.kernel.org/r/20220712210603.123791-1-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/verifier.c | 66 +++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 28 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f0dd73bf69ddf..20df58c351abf 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5533,17 +5533,6 @@ static bool arg_type_is_mem_size(enum bpf_arg_type type) type == ARG_CONST_SIZE_OR_ZERO; }
-static bool arg_type_is_alloc_size(enum bpf_arg_type type) -{ - return type == ARG_CONST_ALLOC_SIZE_OR_ZERO; -} - -static bool arg_type_is_int_ptr(enum bpf_arg_type type) -{ - return type == ARG_PTR_TO_INT || - type == ARG_PTR_TO_LONG; -} - static bool arg_type_is_release(enum bpf_arg_type type) { return type & OBJ_RELEASE; @@ -5929,7 +5918,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, meta->ref_obj_id = reg->ref_obj_id; }
- if (arg_type == ARG_CONST_MAP_PTR) { + switch (base_type(arg_type)) { + case ARG_CONST_MAP_PTR: /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ if (meta->map_ptr) { /* Use map_uid (which is unique id of inner map) to reject: @@ -5954,7 +5944,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, } meta->map_ptr = reg->map_ptr; meta->map_uid = reg->map_uid; - } else if (arg_type == ARG_PTR_TO_MAP_KEY) { + break; + case ARG_PTR_TO_MAP_KEY: /* bpf_map_xxx(..., map_ptr, ..., key) call: * check that [key, key + map->key_size) are within * stack limits and initialized @@ -5971,7 +5962,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, err = check_helper_mem_access(env, regno, meta->map_ptr->key_size, false, NULL); - } else if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) { + break; + case ARG_PTR_TO_MAP_VALUE: if (type_may_be_null(arg_type) && register_is_null(reg)) return 0;
@@ -5987,14 +5979,16 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, err = check_helper_mem_access(env, regno, meta->map_ptr->value_size, false, meta); - } else if (arg_type == ARG_PTR_TO_PERCPU_BTF_ID) { + break; + case ARG_PTR_TO_PERCPU_BTF_ID: if (!reg->btf_id) { verbose(env, "Helper has invalid btf_id in R%d\n", regno); return -EACCES; } meta->ret_btf = reg->btf; meta->ret_btf_id = reg->btf_id; - } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { + break; + case ARG_PTR_TO_SPIN_LOCK: if (meta->func_id == BPF_FUNC_spin_lock) { if (process_spin_lock(env, regno, true)) return -EACCES; @@ -6005,12 +5999,15 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, verbose(env, "verifier internal error\n"); return -EFAULT; } - } else if (arg_type == ARG_PTR_TO_TIMER) { + break; + case ARG_PTR_TO_TIMER: if (process_timer_func(env, regno, meta)) return -EACCES; - } else if (arg_type == ARG_PTR_TO_FUNC) { + break; + case ARG_PTR_TO_FUNC: meta->subprogno = reg->subprogno; - } else if (base_type(arg_type) == ARG_PTR_TO_MEM) { + break; + case ARG_PTR_TO_MEM: /* The access to this pointer is only checked when we hit the * next is_mem_size argument below. */ @@ -6020,11 +6017,14 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, fn->arg_size[arg], false, meta); } - } else if (arg_type_is_mem_size(arg_type)) { - bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); - - err = check_mem_size_reg(env, reg, regno, zero_size_allowed, meta); - } else if (arg_type_is_dynptr(arg_type)) { + break; + case ARG_CONST_SIZE: + err = check_mem_size_reg(env, reg, regno, false, meta); + break; + case ARG_CONST_SIZE_OR_ZERO: + err = check_mem_size_reg(env, reg, regno, true, meta); + break; + case ARG_PTR_TO_DYNPTR: if (arg_type & MEM_UNINIT) { if (!is_dynptr_reg_valid_uninit(env, reg)) { verbose(env, "Dynptr has to be an uninitialized dynptr\n"); @@ -6058,21 +6058,28 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, err_extra, arg + 1); return -EINVAL; } - } else if (arg_type_is_alloc_size(arg_type)) { + break; + case ARG_CONST_ALLOC_SIZE_OR_ZERO: if (!tnum_is_const(reg->var_off)) { verbose(env, "R%d is not a known constant'\n", regno); return -EACCES; } meta->mem_size = reg->var_off.value; - } else if (arg_type_is_int_ptr(arg_type)) { + break; + case ARG_PTR_TO_INT: + case ARG_PTR_TO_LONG: + { int size = int_ptr_type_to_size(arg_type);
err = check_helper_mem_access(env, regno, size, false, meta); if (err) return err; err = check_ptr_alignment(env, reg, 0, size, true); - } else if (arg_type == ARG_PTR_TO_CONST_STR) { + break; + } + case ARG_PTR_TO_CONST_STR: + { struct bpf_map *map = reg->map_ptr; int map_off; u64 map_addr; @@ -6111,9 +6118,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, verbose(env, "string is not zero-terminated\n"); return -EINVAL; } - } else if (arg_type == ARG_PTR_TO_KPTR) { + break; + } + case ARG_PTR_TO_KPTR: if (process_kptr_func(env, regno, meta)) return -EACCES; + break; }
return err;