On 4/25/23 10:35 AM, Roberto Sassu wrote:
From: Roberto Sassu roberto.sassu@huawei.com
Introduce the bpf_verify_umd_signature() kfunc, to verify UMD-parsed signatures. The parameters and usage are the same as for bpf_verify_pkcs7_signature().
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com
kernel/trace/bpf_trace.c | 69 ++++++++++++++++++++++++++++++++-------- 1 file changed, 55 insertions(+), 14 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e8da032bb6f..c9cae337596 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1271,7 +1271,7 @@ __bpf_kfunc struct bpf_key *bpf_lookup_user_key(u32 serial, u64 flags)
- The key pointer is marked as invalid, to prevent bpf_key_put() from
- attempting to decrement the key reference count on that pointer. The key
- pointer set in such way is currently understood only by
- verify_pkcs7_signature().
- verify_pkcs7_signature() and verify_umd_signature().
- Set *id* to one of the values defined in include/linux/verification.h:
- 0 for the primary keyring (immutable keyring of system keys);
@@ -1317,6 +1317,27 @@ __bpf_kfunc void bpf_key_put(struct bpf_key *bkey) } #ifdef CONFIG_SYSTEM_DATA_VERIFICATION +static int validate_key(struct bpf_key *trusted_keyring) +{
- int ret = 0;
- if (trusted_keyring->has_ref) {
/** Do the permission check deferred in bpf_lookup_user_key().* See bpf_lookup_user_key() for more details.** A call to key_task_permission() here would be redundant, as* it is already done by keyring_search() called by* find_asymmetric_key().*/ret = key_validate(trusted_keyring->key);if (ret < 0)return ret;
The above if (ret < 0) return ret; can be removed.
- }
- return ret;
+}
- /**
- bpf_verify_pkcs7_signature - verify a PKCS#7 signature
- @data_ptr: data to verify
@@ -1334,19 +1355,9 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, { int ret;
- if (trusted_keyring->has_ref) {
/** Do the permission check deferred in bpf_lookup_user_key().* See bpf_lookup_user_key() for more details.** A call to key_task_permission() here would be redundant, as* it is already done by keyring_search() called by* find_asymmetric_key().*/ret = key_validate(trusted_keyring->key);if (ret < 0)return ret;- }
- ret = validate_key(trusted_keyring);
- if (ret < 0)
return ret;return verify_pkcs7_signature(data_ptr->data, bpf_dynptr_get_size(data_ptr), @@ -1356,6 +1367,35 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr, VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL); }
+/**
- bpf_verify_umd_signature - Verify a UMD-parsed signature
- @data_ptr: Data to verify
- @sig_ptr: Signature of the data
- @trusted_keyring: Keyring with keys trusted for signature verification
- Verify the UMD-parsed signature *sig_ptr* against the supplied *data_ptr*
- with keys in a keyring referenced by *trusted_keyring*.
- Return: 0 on success, a negative value on error.
- */
+__bpf_kfunc int bpf_verify_umd_signature(struct bpf_dynptr_kern *data_ptr,
struct bpf_dynptr_kern *sig_ptr,struct bpf_key *trusted_keyring)+{
- int ret;
- ret = validate_key(trusted_keyring);
- if (ret < 0)
return ret;- return verify_umd_signature(data_ptr->data,
bpf_dynptr_get_size(data_ptr),sig_ptr->data, bpf_dynptr_get_size(sig_ptr),trusted_keyring->key,VERIFYING_UNSPECIFIED_SIGNATURE, NULL,NULL);+} #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ __diag_pop(); @@ -1366,6 +1406,7 @@ BTF_ID_FLAGS(func, bpf_lookup_system_key, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE) #ifdef CONFIG_SYSTEM_DATA_VERIFICATION BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_verify_umd_signature, KF_SLEEPABLE) #endif BTF_SET8_END(key_sig_kfunc_set)