[PATCH 5.15 07/33] bpf: Convert PTR_TO_MEM_OR_NULL to composable types.

Greg Kroah-Hartman
2022-04-29T10:46:56Z

From: Hao Luo <haoluo@google.com>

commit cf9f2f8d62eca810afbd1ee6cc0800202b000e57 upstream.

Remove PTR_TO_MEM_OR_NULL and replace it with PTR_TO_MEM combined with
flag PTR_MAYBE_NULL.

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211217003152.48334-7-haoluo@google.com
Cc: stable@vger.kernel.org # 5.15.x
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/bpf.h | 1 -
kernel/bpf/btf.c | 2 +-
kernel/bpf/verifier.c | 2 +-
3 files changed, 2 insertions(+), 3 deletions(-)

--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -502,7 +502,6 @@ enum bpf_reg_type {
PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | PTR_TO_BTF_ID,
- PTR_TO_MEM_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MEM,

/* This must be the last entry. Its purpose is to ensure the enum is
* wide enough to hold the higher bits reserved for bpf_type_flag.
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5719,7 +5719,7 @@ int btf_prepare_func_args(struct bpf_ver
return -EINVAL;
}

- reg->type = PTR_TO_MEM_OR_NULL;
+ reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
reg->id = ++env->id_gen;

continue;
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13135,7 +13135,7 @@ static int do_check_common(struct bpf_ve
mark_reg_known_zero(env, regs, i);
else if (regs[i].type == SCALAR_VALUE)
mark_reg_unknown(env, regs, i);
- else if (regs[i].type == PTR_TO_MEM_OR_NULL) {
+ else if (base_type(regs[i].type) == PTR_TO_MEM) {
const u32 mem_size = regs[i].mem_size;

mark_reg_known_zero(env, regs, i);