One time test at startup to ensure either kernel version v4.9 or later,
*or* that required AES-CCM support has been back-ported. If support not
there, daemon will run without providing D-Bus service or attaching to
controllers (prevents systemd thrashing).
---
mesh/crypto.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
mesh/crypto.h | 1 +
mesh/main.c | 7 +++++++
3 files changed, 62 insertions(+)
diff --git a/mesh/crypto.c b/mesh/crypto.c
index a6dc7ffe2..cebdffe45 100644
--- a/mesh/crypto.c
+++ b/mesh/crypto.c
@@ -1130,3 +1130,57 @@ bool mesh_crypto_check_fcs(const uint8_t *packet, uint8_t packet_len,
return fcs == 0xcf;
}
+
+/* This function performs a quick-check of ELL and Kernel AEAD encryption.
+ * Some kernel versions before v4.9 have a known AEAD bug. If the system
+ * running this test is using a v4.8 or earlier kernel, a failure here is
+ * likely unless AEAD encryption has been backported.
+ */
+static const uint8_t crypto_test_result[] = {
+ 0x75, 0x03, 0x7e, 0xe2, 0x89, 0x81, 0xbe, 0x59,
+ 0xbc, 0xe6, 0xdd, 0x23, 0x63, 0x5b, 0x16, 0x61,
+ 0xb7, 0x23, 0x92, 0xd4, 0x86, 0xee, 0x84, 0x29,
+ 0x9a, 0x2a, 0xbf, 0x96
+};
+
+bool mesh_crypto_check_avail()
+{
+ void *cipher;
+ bool result;
+ uint8_t i;
+ union {
+ struct {
+ uint8_t key[16];
+ uint8_t aad[16];
+ uint8_t nonce[13];
+ uint8_t data[20];
+ uint8_t mic[8];
+ } crypto;
+ uint8_t bytes[0];
+ } u;
+ uint8_t out_msg[sizeof(u.crypto.data) + sizeof(u.crypto.mic)];
+
+ l_debug("Testing Crypto");
+ for (i = 0; i < sizeof(u); i++) {
+ u.bytes[i] = 0x60 + i;
+ }
+
+ cipher = l_aead_cipher_new(L_AEAD_CIPHER_AES_CCM, u.crypto.key,
+ sizeof(u.crypto.key), sizeof(u.crypto.mic));
+
+ if (!cipher)
+ return false;
+
+ result = l_aead_cipher_encrypt(cipher,
+ u.crypto.data, sizeof(u.crypto.data),
+ u.crypto.aad, sizeof(u.crypto.aad),
+ u.crypto.nonce, sizeof(u.crypto.nonce),
+ out_msg, sizeof(out_msg));
+
+ if (result)
+ result = !memcmp(out_msg, crypto_test_result, sizeof(out_msg));
+
+ l_aead_cipher_free(cipher);
+
+ return result;
+}
diff --git a/mesh/crypto.h b/mesh/crypto.h
index 1a73bcaa3..e5ce840b4 100644
--- a/mesh/crypto.h
+++ b/mesh/crypto.h
@@ -161,3 +161,4 @@ bool mesh_crypto_check_fcs(const uint8_t *packet, uint8_t packet_len,
uint8_t received_fcs);
bool mesh_crypto_aes_cmac(const uint8_t key[16], const uint8_t *msg,
size_t msg_len, uint8_t res[16]);
+bool mesh_crypto_check_avail(void);
diff --git a/mesh/main.c b/mesh/main.c
index 262e3da48..273651f97 100644
--- a/mesh/main.c
+++ b/mesh/main.c
@@ -34,6 +34,7 @@
#include "lib/mgmt.h"
#include "mesh/mesh.h"
+#include "mesh/crypto.h"
#include "mesh/dbus.h"
#include "mesh/mesh-io.h"
@@ -121,6 +122,12 @@ int main(int argc, char *argv[])
l_log_set_stderr();
+ if (!mesh_crypto_check_avail()) {
+ l_error("Mesh Crypto functions unavailable");
+ status = l_main_run_with_signal(signal_handler, NULL);
+ goto done;
+ }
+
for (;;) {
int opt;
const char *str;
--
2.21.0
