Check arguments to fr_sim_crypto_sign_packet

...and add helful debugging output for developers.

eapol_test provides similar debugging output, so when something's not working it makes it very easy to see which cryptographic input/output was incorrect.

diff --git a/src/modules/rlm_eap/lib/sim/crypto.c b/src/modules/rlm_eap/lib/sim/crypto.c
index d74b1ec5ff1a84e9a00b9ffb53b360b29c31e26e..60ca5939080b1f8181bea78cba83e8d440e82710 100644 (file)
--- a/src/modules/rlm_eap/lib/sim/crypto.c
+++ b/src/modules/rlm_eap/lib/sim/crypto.c
@@ -236,6 +236,22 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
        eap_packet_raw_t        eap_hdr;
        uint16_t                packet_len;
 
+       if (unlikely(!eap_packet)) {
+               fr_strerror_printf("Invalid argument: eap_packet is NULL");
+               return -1;
+       }
+
+       if (unlikely(!md)) {
+               fr_strerror_printf("Invalid argument: md is NULL");
+               return -1;
+       }
+
+       if (unlikely(!key) || (key_len == 0)) {
+               fr_strerror_printf("Invalid argument: key is NULL");
+               return -1;
+       }
+
+       FR_PROTO_HEX_DUMP("MAC key", key, key_len);
        pkey = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, key, key_len);
        if (!pkey) {
                tls_strerror_printf(true, "Failed creating HMAC signing key");
@@ -267,7 +283,7 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
        memcpy(&eap_hdr.length, &packet_len, sizeof(packet_len));
        eap_hdr.data[0] = eap_packet->type.num;
 
-       FR_PROTO_HEX_DUMP("hmac input eap_hdr", (uint8_t *)&eap_hdr, sizeof(eap_hdr));
+       FR_PROTO_HEX_DUMP("MAC digest input (eap header)", (uint8_t *)&eap_hdr, sizeof(eap_hdr));
        if (EVP_DigestSignUpdate(md_ctx, &eap_hdr, sizeof(eap_hdr)) != 1) {
                tls_strerror_printf(true, "Failed digesting EAP data");
                goto error;
@@ -283,6 +299,9 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
                {
                        uint8_t zero[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+
+                       FR_PROTO_HEX_DUMP("MAC digest input", p, mac - p);
+
                        /*
                         *      Digest everything up to the hash
                         *      part of the AT_MAC, including
@@ -294,6 +313,8 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
                        }
                        p += mac - p;
 
+
+                       FR_PROTO_HEX_DUMP("MAC digest input", zero, sizeof(zero));
                        /*
                         *      Feed in 16 bytes of zeroes to
                         *      simulated the zeroed out Mac.
@@ -315,12 +336,17 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
                }
        }
 
-       /*
-        *      Digest the rest of the packet.
-        */
-       if (EVP_DigestSignUpdate(md_ctx, p, end - p) != 1) {
-               tls_strerror_printf(true, "Failed digesting packet data");
-               goto error;
+
+       if (p < end) {
+               FR_PROTO_HEX_DUMP("MAC digest input", p, (end - p));
+
+               /*
+                *      Digest the rest of the packet.
+                */
+               if (EVP_DigestSignUpdate(md_ctx, p, end - p) != 1) {
+                       tls_strerror_printf(true, "Failed digesting packet data");
+                       goto error;
+               }
        }
 
        /*
@@ -330,7 +356,7 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
         *      a concatenation of packet data, and something extra...
         */
        if (hmac_extra) {
-               FR_PROTO_HEX_DUMP("hmac input hmac_extra", hmac_extra, hmac_extra_len);
+               FR_PROTO_HEX_DUMP("MAC digest input (extra)", hmac_extra, hmac_extra_len);
                if (EVP_DigestSignUpdate(md_ctx, hmac_extra, hmac_extra_len) != 1) {
                        tls_strerror_printf(true, "Failed digesting HMAC extra data");
                        goto error;
@@ -342,9 +368,7 @@ ssize_t fr_sim_crypto_sign_packet(uint8_t out[16], eap_packet_t *eap_packet, boo
                goto error;
        }
 
-       if (!fr_cond_assert(digest_len >= sizeof(digest))) goto error;
-
-       FR_PROTO_HEX_DUMP("hmac output", digest, digest_len);
+       FR_PROTO_HEX_DUMP("MAC", digest, digest_len);
 
        /*
         *      Truncate by four bytes.
@@ -662,7 +686,7 @@ static int fr_sim_crypto_aka_prime_prf(uint8_t *out, size_t outlen,
                if ((p != out) && EVP_DigestSignUpdate(md_ctx, digest, sizeof(digest)) != 1) goto error;/* Ingest last round */
                if (EVP_DigestSignUpdate(md_ctx, in, in_len) != 1) goto error;                          /* Ingest s */
                if (EVP_DigestSignUpdate(md_ctx, &c, sizeof(c)) != 1) goto error;                       /* Ingest round number */
-               if (EVP_DigestSignFinal(md_ctx, digest, &len) != 1) goto error;                                 /* Output T(i) */
+               if (EVP_DigestSignFinal(md_ctx, digest, &len) != 1) goto error;                         /* Output T(i) */
 
                copy = p - end;
                if (copy > SHA256_DIGEST_LENGTH) copy = SHA256_DIGEST_LENGTH;