[LTP] [PATCH v2 25/33] keyctl32: Test KEYCTL_PKEY_SIGN and VERIFY

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

Test public key signature creation and verification with
KEYCTL_PKEY_SIGN and KEYCTL_PKEY_VERIFY: sign a 32-byte digest
using an RSA-2048 PKCS#8 private key with enc=pkcs1, verify
the 256-byte signature with the matching X.509 public key,
and verify that a mismatched digest fails with EKEYREJECTED.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 runtest/syscalls                            |   1 +
 testcases/kernel/syscalls/keyctl/.gitignore |   1 +
 testcases/kernel/syscalls/keyctl/keyctl32.c | 121 ++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+)

diff --git a/runtest/syscalls b/runtest/syscalls
index e43dd02ab..d4007f7a6 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -749,6 +749,7 @@ keyctl28 keyctl28
 keyctl29 keyctl29
 keyctl30 keyctl30
 keyctl31 keyctl31
+keyctl32 keyctl32
 
 kcmp01 kcmp01
 kcmp02 kcmp02
diff --git a/testcases/kernel/syscalls/keyctl/.gitignore b/testcases/kernel/syscalls/keyctl/.gitignore
index 025dc27fc..8b1627bee 100644
--- a/testcases/kernel/syscalls/keyctl/.gitignore
+++ b/testcases/kernel/syscalls/keyctl/.gitignore
@@ -29,3 +29,4 @@
 /keyctl29
 /keyctl30
 /keyctl31
+/keyctl32
diff --git a/testcases/kernel/syscalls/keyctl/keyctl32.c b/testcases/kernel/syscalls/keyctl/keyctl32.c
new file mode 100644
index 000000000..4a00225f6
--- /dev/null
+++ b/testcases/kernel/syscalls/keyctl/keyctl32.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2026 Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * Test ``KEYCTL_PKEY_SIGN`` and ``KEYCTL_PKEY_VERIFY`` of :manpage:`keyctl(2)`.
+ *
+ * ``KEYCTL_PKEY_SIGN`` signs a digest using an asymmetric private key and
+ * ``KEYCTL_PKEY_VERIFY`` verifies the signature using the matching public key.
+ *
+ * Requires root (CAP_SYS_MODULE) to load the ``x509_key_parser`` and
+ * ``pkcs8_key_parser`` modules.
+ *
+ * [Algorithm]
+ *
+ * - sign a 32-byte digest using an RSA-2048 PKCS#8 private key with
+ *   ``enc=pkcs1 hash=sha256``
+ * - verify the 256-byte signature using the matching X.509 public key
+ * - verify a mismatched digest fails verification with ``EKEYREJECTED``
+ */
+
+#include "keyctl_common.h"
+#include "keyctl_pkey_data.h"
+#include "tst_module.h"
+
+#define DIGEST_SIZE	32
+#define SIG_SIZE	256
+
+static const unsigned char digest[DIGEST_SIZE] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+	0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+};
+
+static unsigned char sig[SIG_SIZE];
+static unsigned char wrong_digest[DIGEST_SIZE];
+
+static key_serial_t cert_key, priv_key;
+static struct keyctl_pkey_params *sign_params;
+static struct keyctl_pkey_params *verify_params;
+
+static void setup(void)
+{
+	SAFE_KEYCTL(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
+
+	tst_modprobe("x509_key_parser", NULL);
+	tst_modprobe("pkcs8_key_parser", NULL);
+
+	cert_key = add_asymmetric_key_or_tconf("cert", rsa2048_cert,
+					       sizeof(rsa2048_cert),
+					       "CONFIG_X509_CERTIFICATE_PARSER");
+	priv_key = add_asymmetric_key_or_tconf("priv", rsa2048_pkcs8,
+					       sizeof(rsa2048_pkcs8),
+					       "CONFIG_PKCS8_PRIVATE_KEY_PARSER");
+}
+
+static void run(void)
+{
+	memset(sig, 0, sizeof(sig));
+
+	memset(sign_params, 0, sizeof(*sign_params));
+	sign_params->key_id = priv_key;
+	sign_params->in_len = DIGEST_SIZE;
+	sign_params->out_len = SIG_SIZE;
+
+	TST_EXP_EQ_LI_SILENT(keyctl(KEYCTL_PKEY_SIGN, (unsigned long)sign_params,
+				    (unsigned long)"enc=pkcs1 hash=sha256",
+				    (unsigned long)digest,
+				    (unsigned long)sig),
+			     SIG_SIZE);
+	if (!TST_PASS)
+		return;
+
+	memset(verify_params, 0, sizeof(*verify_params));
+	verify_params->key_id = cert_key;
+	verify_params->in_len = DIGEST_SIZE;
+	verify_params->in2_len = SIG_SIZE;
+
+	TST_EXP_EQ_LI_SILENT(keyctl(KEYCTL_PKEY_VERIFY, (unsigned long)verify_params,
+				    (unsigned long)"enc=pkcs1 hash=sha256",
+				    (unsigned long)digest,
+				    (unsigned long)sig),
+			     0);
+	if (!TST_PASS)
+		return;
+
+	tst_res(TPASS, "KEYCTL_PKEY_SIGN and KEYCTL_PKEY_VERIFY roundtrip succeeded");
+
+	memcpy(wrong_digest, digest, sizeof(wrong_digest));
+	wrong_digest[0] ^= 0xff;
+
+	TST_EXP_FAIL(keyctl(KEYCTL_PKEY_VERIFY, (unsigned long)verify_params,
+			    (unsigned long)"enc=pkcs1 hash=sha256",
+			    (unsigned long)wrong_digest,
+			    (unsigned long)sig),
+		     EKEYREJECTED,
+		     "KEYCTL_PKEY_VERIFY with mismatched digest");
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.test_all = run,
+	.min_kver = "4.20",
+	.needs_root = 1,
+	.needs_kconfigs = (const char *[]) {
+		"CONFIG_KEYS=y",
+		"CONFIG_ASYMMETRIC_KEY_TYPE=y",
+		"CONFIG_X509_CERTIFICATE_PARSER",
+		"CONFIG_PKCS8_PRIVATE_KEY_PARSER",
+		"CONFIG_CRYPTO_RSA",
+		"CONFIG_CRYPTO_SHA256",
+		NULL
+	},
+	.bufs = (struct tst_buffers []) {
+		{&sign_params, .size = sizeof(*sign_params)},
+		{&verify_params, .size = sizeof(*verify_params)},
+		{},
+	},
+};

-- 
2.51.0