From 44e9a741cad824f45112b79c21d88c201d5aec13 Mon Sep 17 00:00:00 2001 From: Shung-Hsi Yu Date: Mon, 7 Mar 2022 13:29:18 +0800 Subject: [PATCH] bpf: Determine buf_info inside check_buffer_access() Instead of determining buf_info string in the caller of check_buffer_access(), we can determine whether the register type is read-only through type_is_rdonly_mem() helper inside check_buffer_access() and construct buf_info, making the code slightly cleaner. Signed-off-by: Shung-Hsi Yu Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/YiWYLnAkEZXBP/gH@syu-laptop --- kernel/bpf/verifier.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ec3a7b6c9515..e34264200e09 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4062,9 +4062,9 @@ static int check_buffer_access(struct bpf_verifier_env *env, const struct bpf_reg_state *reg, int regno, int off, int size, bool zero_size_allowed, - const char *buf_info, u32 *max_access) { + const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr"; int err; err = __check_buffer_access(env, buf_info, reg, regno, off, size); @@ -4576,7 +4576,6 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn value_regno); } else if (base_type(reg->type) == PTR_TO_BUF) { bool rdonly_mem = type_is_rdonly_mem(reg->type); - const char *buf_info; u32 *max_access; if (rdonly_mem) { @@ -4585,15 +4584,13 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn regno, reg_type_str(env, reg->type)); return -EACCES; } - buf_info = "rdonly"; max_access = &env->prog->aux->max_rdonly_access; } else { - buf_info = "rdwr"; max_access = &env->prog->aux->max_rdwr_access; } err = check_buffer_access(env, reg, regno, off, size, false, - buf_info, max_access); + max_access); if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ)) mark_reg_unknown(env, regs, value_regno); @@ -4856,7 +4853,6 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, struct bpf_call_arg_meta *meta) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; - const char *buf_info; u32 *max_access; switch (base_type(reg->type)) { @@ -4883,15 +4879,13 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, if (meta && meta->raw_mode) return -EACCES; - buf_info = "rdonly"; max_access = &env->prog->aux->max_rdonly_access; } else { - buf_info = "rdwr"; max_access = &env->prog->aux->max_rdwr_access; } return check_buffer_access(env, reg, regno, reg->off, access_size, zero_size_allowed, - buf_info, max_access); + max_access); case PTR_TO_STACK: return check_stack_range_initialized( env, -- 2.39.5