From: Amery Hung <ameryhung@gmail.com>
To: bpf@vger.kernel.org
Cc: alexei.starovoitov@gmail.com, andrii@kernel.org,
daniel@iogearbox.net, eddyz87@gmail.com, memxor@gmail.com,
ameryhung@gmail.com, kernel-team@meta.com
Subject: [PATCH bpf-next v3 04/18] bpf: Pass kfunc meta to mem and mem_size check
Date: Sat, 1 Aug 2026 00:46:19 -0700 [thread overview]
Message-ID: <20260801074633.1595644-5-ameryhung@gmail.com> (raw)
In-Reply-To: <20260801074633.1595644-1-ameryhung@gmail.com>
kfunc now shares the same bpf_call_arg_meta with helpers. Pass kfunc's
own meta to check_mem_reg() and check_kfunc_mem_size() instead of NULL
or a temporary meta on the stack.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
kernel/bpf/verifier.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 15422e8d7e23..d10b2dc2d628 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6924,7 +6924,7 @@ static int check_mem_size_reg(struct bpf_verifier_env *env,
}
static int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
- argno_t argno, u32 mem_size)
+ argno_t argno, u32 mem_size, struct bpf_call_arg_meta *meta)
{
bool may_be_null = type_may_be_null(reg->type);
struct bpf_reg_state saved_reg;
@@ -6950,8 +6950,8 @@ static int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg
int size = base_type(reg->type) == PTR_TO_STACK ? -(int)mem_size : mem_size;
- err = check_helper_mem_access(env, reg, argno, size, BPF_READ, true, NULL);
- err = err ?: check_helper_mem_access(env, reg, argno, size, BPF_WRITE, true, NULL);
+ err = check_helper_mem_access(env, reg, argno, size, BPF_READ, true, meta);
+ err = err ?: check_helper_mem_access(env, reg, argno, size, BPF_WRITE, true, meta);
if (may_be_null)
*reg = saved_reg;
@@ -6994,22 +6994,20 @@ static int process_const_alloc_mem_size(struct bpf_verifier_env *env, struct bpf
}
static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *mem_reg,
- struct bpf_reg_state *size_reg, argno_t mem_argno, argno_t size_argno)
+ struct bpf_reg_state *size_reg, argno_t mem_argno,
+ argno_t size_argno, struct bpf_call_arg_meta *meta)
{
bool may_be_null = type_may_be_null(mem_reg->type);
struct bpf_reg_state saved_reg;
- struct bpf_call_arg_meta meta;
int err;
- memset(&meta, 0, sizeof(meta));
-
if (may_be_null) {
saved_reg = *mem_reg;
mark_ptr_not_null_reg(mem_reg);
}
- err = check_mem_size_reg(env, mem_reg, size_reg, mem_argno, size_argno, BPF_READ, true, &meta);
- err = err ?: check_mem_size_reg(env, mem_reg, size_reg, mem_argno, size_argno, BPF_WRITE, true, &meta);
+ err = check_mem_size_reg(env, mem_reg, size_reg, mem_argno, size_argno, BPF_READ, true, meta);
+ err = err ?: check_mem_size_reg(env, mem_reg, size_reg, mem_argno, size_argno, BPF_WRITE, true, meta);
if (may_be_null)
*mem_reg = saved_reg;
@@ -9258,7 +9256,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog,
ret = check_func_arg_reg_off(env, reg, argno, ARG_DONTCARE);
if (ret < 0)
return ret;
- if (check_mem_reg(env, reg, argno, arg->mem_size))
+ if (check_mem_reg(env, reg, argno, arg->mem_size, NULL))
return -EINVAL;
if (!(arg->arg_type & PTR_MAYBE_NULL) &&
(type_may_be_null(reg->type) || bpf_register_is_null(reg))) {
@@ -12405,7 +12403,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_call_arg_me
ref_tname, PTR_ERR(resolve_ret));
return -EINVAL;
}
- ret = check_mem_reg(env, reg, argno, type_size);
+ ret = check_mem_reg(env, reg, argno, type_size, meta);
if (ret < 0)
return ret;
break;
@@ -12419,7 +12417,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_call_arg_me
if (!bpf_register_is_null(buff_reg) || !is_kfunc_arg_nullable(meta->btf, buff_arg)) {
ret = check_kfunc_mem_size_reg(env, buff_reg, size_reg,
- argno, next_argno);
+ argno, next_argno, meta);
if (ret < 0) {
verbose(env, "%s and ", reg_arg_name(env, argno));
verbose(env, "%s memory, len pair leads to invalid memory access\n",
--
2.52.0
next prev parent reply other threads:[~2026-08-01 7:46 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-01 7:46 [PATCH bpf-next v3 00/18] Generate bpf_func_proto for kfunc Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 01/18] bpf: Drop process_timer_func wrappers Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 02/18] bpf: Unify const map ptr argument checking for helpers and kfuncs Amery Hung
2026-08-01 8:03 ` sashiko-bot
2026-08-01 7:46 ` [PATCH bpf-next v3 03/18] bpf: Split kfunc map argument into __const_map and __map Amery Hung
2026-08-01 7:46 ` Amery Hung [this message]
2026-08-01 7:46 ` [PATCH bpf-next v3 05/18] bpf: Resolve map lookup result type at lookup time Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 06/18] bpf: Check helper and kfunc mem+size arguments identically Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 07/18] selftests/bpf: Test map lookup result refinement Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 08/18] bpf: Check fixed-size mem args of helpers and kfuncs the same way Amery Hung
2026-08-01 8:17 ` sashiko-bot
2026-08-01 7:46 ` [PATCH bpf-next v3 09/18] bpf: Rename ARG_CONST_SIZE{,_OR_ZERO} to ARG_MEM_SIZE{,_OR_ZERO} Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 10/18] bpf: Fold __szk const size handling into the scalar arg path Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 11/18] selftests/bpf: Test __szk precision with a NULL nullable buffer Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 12/18] bpf: Classify kfunc mem_size args from BTF without register state Amery Hung
2026-08-01 8:09 ` sashiko-bot
2026-08-01 7:46 ` [PATCH bpf-next v3 13/18] bpf: Handle NULL kfunc pointer args without a KF_ARG_PTR_TO_NULL type Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 14/18] bpf: Distinguish fixed- and variable-size kfunc mem args with MEM_FIXED_SIZE Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 15/18] bpf: Classify kfunc pointer arguments from BTF, resolve type against the register Amery Hung
2026-08-01 8:22 ` sashiko-bot
2026-08-01 7:46 ` [PATCH bpf-next v3 16/18] bpf: Tag nullable kfunc pointer args with PTR_MAYBE_NULL Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 17/18] bpf: Classify scalar kfunc arguments from BTF Amery Hung
2026-08-01 7:46 ` [PATCH bpf-next v3 18/18] bpf: Generate kfunc argument prototype at add-call time Amery Hung
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