From: Roberto Sassu <roberto.sassu@huawei.com>
To: <ast@kernel.org>, <daniel@iogearbox.net>, <andrii@kernel.org>,
<martin.lau@linux.dev>, <song@kernel.org>, <yhs@fb.com>,
<john.fastabend@gmail.com>, <kpsingh@kernel.org>,
<sdf@google.com>, <haoluo@google.com>, <jolsa@kernel.org>,
<mykolal@fb.com>, <corbet@lwn.net>, <dhowells@redhat.com>,
<jarkko@kernel.org>, <rostedt@goodmis.org>, <mingo@redhat.com>,
<paul@paul-moore.com>, <jmorris@namei.org>, <serge@hallyn.com>,
<shuah@kernel.org>
Cc: <bpf@vger.kernel.org>, <linux-doc@vger.kernel.org>,
<keyrings@vger.kernel.org>,
<linux-security-module@vger.kernel.org>,
<linux-kselftest@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Roberto Sassu <roberto.sassu@huawei.com>,
Joanne Koong <joannelkoong@gmail.com>
Subject: [PATCH v11 2/9] btf: Handle dynamic pointer parameter in kfuncs
Date: Fri, 12 Aug 2022 12:18:55 +0200 [thread overview]
Message-ID: <20220812101902.2846182-3-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20220812101902.2846182-1-roberto.sassu@huawei.com>
Allow the bpf_dynptr_kern parameter to be specified in kfuncs. Also, ensure
that the dynamic pointer is valid and initialized.
Cc: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
include/linux/bpf_verifier.h | 3 +++
kernel/bpf/btf.c | 22 ++++++++++++++++++++++
kernel/bpf/verifier.c | 4 ++--
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 2e3bad8640dc..55876fbdbae2 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -560,6 +560,9 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state
u32 regno);
int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
u32 regno, u32 mem_size);
+bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ enum bpf_arg_type arg_type);
/* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index e49b3b6d48ad..86e63f2ee5da 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -195,6 +195,10 @@
i < btf_type_vlen(struct_type); \
i++, member++)
+#define stringify_struct(x) \
+ ({ BUILD_BUG_ON(sizeof(struct x) < 0); \
+ __stringify(x); })
+
DEFINE_IDR(btf_idr);
DEFINE_SPINLOCK(btf_idr_lock);
@@ -6362,15 +6366,20 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
if (is_kfunc) {
bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]);
+ bool arg_dynptr = btf_type_is_struct(ref_t) &&
+ !strcmp(ref_tname,
+ stringify_struct(bpf_dynptr_kern));
/* Permit pointer to mem, but only when argument
* type is pointer to scalar, or struct composed
* (recursively) of scalars.
* When arg_mem_size is true, the pointer can be
* void *.
+ * Also permit initialized dynamic pointers.
*/
if (!btf_type_is_scalar(ref_t) &&
!__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
+ !arg_dynptr &&
(arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
bpf_log(log,
"arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
@@ -6378,6 +6387,19 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
return -EINVAL;
}
+ if (arg_dynptr) {
+ if (!is_dynptr_reg_valid_init(env, reg,
+ ARG_PTR_TO_DYNPTR)) {
+ bpf_log(log,
+ "arg#%d pointer type %s %s must be initialized\n",
+ i, btf_type_str(ref_t),
+ ref_tname);
+ return -EINVAL;
+ }
+
+ continue;
+ }
+
/* Check for mem, len pair */
if (arg_mem_size) {
if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2c1f8069f7b7..aa834e7bb296 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -779,8 +779,8 @@ static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_
return true;
}
-static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
- enum bpf_arg_type arg_type)
+bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ enum bpf_arg_type arg_type)
{
struct bpf_func_state *state = func(env, reg);
int spi = get_spi(reg->off);
--
2.25.1
next prev parent reply other threads:[~2022-08-12 10:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-12 10:18 [PATCH v11 0/9] bpf: Add kfuncs for PKCS#7 signature verification Roberto Sassu
2022-08-12 10:18 ` [PATCH v11 1/9] bpf: Allow kfuncs to be used in LSM programs Roberto Sassu
2022-08-12 10:18 ` Roberto Sassu [this message]
2022-08-15 16:45 ` [PATCH v11 2/9] btf: Handle dynamic pointer parameter in kfuncs Daniel Borkmann
2022-08-12 10:18 ` [PATCH v11 3/9] bpf: Export bpf_dynptr_get_size() Roberto Sassu
2022-08-12 10:18 ` [PATCH v11 4/9] KEYS: Move KEY_LOOKUP_ to include/linux/key.h Roberto Sassu
2022-08-12 10:18 ` [PATCH v11 5/9] bpf: Add bpf_lookup_*_key() and bpf_key_put() kfuncs Roberto Sassu
2022-08-12 10:18 ` [PATCH v11 6/9] bpf: Add bpf_verify_pkcs7_signature() kfunc Roberto Sassu
2022-08-12 10:19 ` [PATCH v11 7/9] selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put() Roberto Sassu
2022-08-12 10:19 ` [PATCH v11 8/9] selftests/bpf: Add additional tests for bpf_lookup_*_key() Roberto Sassu
2022-08-12 10:19 ` [PATCH v11 9/9] selftests/bpf: Add test for bpf_verify_pkcs7_signature() kfunc Roberto Sassu
2022-08-15 16:10 ` [PATCH v11 0/9] bpf: Add kfuncs for PKCS#7 signature verification Daniel Borkmann
2022-08-16 7:12 ` Roberto Sassu
2022-08-16 10:05 ` Daniel Borkmann
2022-08-16 12:15 ` Roberto Sassu
2022-08-16 16:39 ` Alexei Starovoitov
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