Allocate stack buffers large enough for the maximum AT_IDENTITY length (1016 bytes)

diff --git a/src/modules/rlm_eap/lib/sim/crypto.c b/src/modules/rlm_eap/lib/sim/crypto.c
index c03f8dd7091048b1ad2721681e1ceb1e11741edc..579502935cd65cf06c30d02168f4890545c98171 100644 (file)
--- a/src/modules/rlm_eap/lib/sim/crypto.c
+++ b/src/modules/rlm_eap/lib/sim/crypto.c
@@ -404,20 +404,20 @@ int fr_sim_crypto_kdf_0_gsm(fr_sim_keys_t *keys)
        fr_sha1_ctx     context;
        uint8_t         fk[160];
 
-       uint8_t         buf[384];
+       uint8_t         buf[SIM_MAX_STRING_LENGTH + sizeof(keys->gsm.nonce_mt) + 2 + sizeof(keys->gsm.version_select)];
        uint8_t         *p;
 
-       size_t          need;
-
        if (!fr_cond_assert(keys->vector_type == SIM_VECTOR_GSM)) return -1;
 
-       need = keys->identity_len + (SIM_VECTOR_GSM_KC_SIZE * 3) + sizeof(keys->gsm.nonce_mt) +
-              keys->gsm.version_list_len + sizeof(keys->gsm.version_select);
-       if (need > sizeof(buf)) {
-               fr_strerror_printf("Identity too long. PRF input is %zu bytes, input buffer is %zu bytes",
-                                  need, sizeof(buf));
-               return -1;
-       }
+       /*
+        *      Our stack buffer should be large enough in
+        *      all cases.
+        */
+       if (!fr_cond_assert((keys->identity_len +
+                           (SIM_VECTOR_GSM_KC_SIZE * 3) +
+                           sizeof(keys->gsm.nonce_mt) +
+                           keys->gsm.version_list_len +
+                           sizeof(keys->gsm.version_select)) <= sizeof(buf))) return -1;
 
        p = buf;
        memcpy(p, keys->identity, keys->identity_len);
@@ -504,19 +504,19 @@ int fr_sim_crypto_kdf_0_umts(fr_sim_keys_t *keys)
 {
        fr_sha1_ctx     context;
        uint8_t         fk[160];
-       uint8_t         buf[384];
+       uint8_t         buf[SIM_MAX_STRING_LENGTH + sizeof(keys->umts.vector.ik) + sizeof(keys->umts.vector.ck)];
        uint8_t         *p;
-       uint8_t         blen;
-       size_t          need;
+       size_t          blen;
 
        if (!fr_cond_assert(keys->vector_type == SIM_VECTOR_UMTS)) return - 1;
 
-       need = keys->identity_len + sizeof(keys->umts.vector.ik) + sizeof(keys->umts.vector.ck);
-       if (need > sizeof(buf)) {
-               fr_strerror_printf("Identity too long. PRF input is %zu bytes, input buffer is %zu bytes",
-                                  need, sizeof(buf));
-               return -1;
-       }
+       /*
+        *      Our stack buffer should be large enough in
+        *      all cases.
+        */
+       if (!fr_cond_assert((keys->identity_len +
+                            sizeof(keys->umts.vector.ik) +
+                            sizeof(keys->umts.vector.ck)) <= sizeof(buf))) return -1;
 
        p = buf;
        memcpy(p, keys->identity, keys->identity_len);
@@ -755,13 +755,14 @@ static int sim_crypto_derive_ck_ik_prime(fr_sim_keys_t *keys)
        uint8_t         digest[sizeof(keys->ik_prime) + sizeof(keys->ck_prime)];
        size_t          len;
 
+       uint8_t         sqn_ak_buff[MILENAGE_SQN_SIZE];
+       uint16_t        l0, l1;
+
        uint8_t         k[sizeof(keys->umts.vector.ik) + sizeof(keys->umts.vector.ck)];
+       uint8_t         s[sizeof(uint8_t) + SIM_MAX_STRING_LENGTH + sizeof(l0) + SIM_SQN_AK_SIZE + sizeof(l1)];
 
-       uint8_t         s[384];
        uint8_t         *p = s;
 
-       uint8_t         sqn_ak_buff[MILENAGE_SQN_SIZE];
-       uint16_t        l0, l1;
        size_t          s_len;
        EVP_PKEY        *pkey;
        EVP_MD_CTX      *md_ctx = NULL;
@@ -770,12 +771,15 @@ static int sim_crypto_derive_ck_ik_prime(fr_sim_keys_t *keys)
 
        uint48_to_buff(sqn_ak_buff, keys->sqn ^ uint48_from_buff(keys->umts.vector.ak));
 
-       s_len = sizeof(uint8_t) + keys->network_len + sizeof(l0) + SIM_SQN_AK_SIZE + sizeof(l1);
-       if (s_len > sizeof(s)) {
-               fr_strerror_printf("Network too long. PRF input is %zu bytes, input buffer is %zu bytes",
-                                  s_len, sizeof(s));
-               return -1;
-       }
+       /*
+        *      Our stack buffer should be large enough in
+        *      all cases.
+        */
+       if (!fr_cond_assert((sizeof(uint8_t) +
+                            keys->network_len +
+                            sizeof(l0) +
+                            SIM_SQN_AK_SIZE +
+                            sizeof(l1)) <= sizeof(s))) return -1;
 
        FR_PROTO_HEX_DUMP("Network", keys->network, keys->network_len);
        FR_PROTO_HEX_DUMP("CK", keys->umts.vector.ck, sizeof(keys->umts.vector.ck));
@@ -798,6 +802,9 @@ static int sim_crypto_derive_ck_ik_prime(fr_sim_keys_t *keys)
 
        l1 = htons(SIM_SQN_AK_SIZE);
        memcpy(p, &l1, sizeof(l1));
+       p += sizeof(l1);
+
+       s_len = p - s;
 
        FR_PROTO_HEX_DUMP("FC || P0 || L0 || P1 || L1 || ... || Pn || Ln", s, s_len);
 
@@ -947,7 +954,8 @@ static int sim_crypto_aka_prime_prf(uint8_t *out, size_t outlen,
 int fr_sim_crypto_kdf_1_umts(fr_sim_keys_t *keys)
 {
        uint8_t k[sizeof(keys->ck_prime) + sizeof(keys->ik_prime)];
-       uint8_t s[384];
+#define KDF_1_S_STATIC "EAP-AKA'"
+       uint8_t s[(sizeof(KDF_1_S_STATIC) - 1) + SIM_MAX_STRING_LENGTH];
        uint8_t *p = s;
 
        uint8_t mk[208];
@@ -957,22 +965,18 @@ int fr_sim_crypto_kdf_1_umts(fr_sim_keys_t *keys)
 
        if (!fr_cond_assert(keys->vector_type == SIM_VECTOR_UMTS)) return -1;
 
-#define KDF_1_S_STATIC "EAP-AKA'"
-
        /*
         *      build s, a concatenation of EAP-AKA' and Identity
         */
-       s_len = (sizeof(KDF_1_S_STATIC) - 1) + keys->identity_len;
-       if (s_len > sizeof(s)) {
-               fr_strerror_printf("Identity too long. PRF input is %zu bytes, input buffer is %zu bytes",
-                                  s_len, sizeof(s));
-               return -1;
-       }
+       if (!fr_cond_assert((sizeof(KDF_1_S_STATIC) - 1) + keys->identity_len <= sizeof(s))) return -1;
 
        memcpy(p, KDF_1_S_STATIC, sizeof(KDF_1_S_STATIC) - 1);
        p += sizeof(KDF_1_S_STATIC) - 1;
 
        memcpy(p, keys->identity, keys->identity_len);
+       p += keys->identity_len;
+
+       s_len = p - s;
 
        /*
         *      build k, a concatenation of IK' and CK'

diff --git a/src/modules/rlm_eap/lib/sim/sim_proto.h b/src/modules/rlm_eap/lib/sim/sim_proto.h
index 3e3801ca3f13f65c04d36824362a777db9ae689f..61aa683dbbd8bd249ad2e8a448cefb7dfedcfc64 100644 (file)
--- a/src/modules/rlm_eap/lib/sim/sim_proto.h
+++ b/src/modules/rlm_eap/lib/sim/sim_proto.h
@@ -37,6 +37,7 @@ RCSIDH(sim_h, "$Id$")
 #include "eap_sim_common.h"
 #include "eap_aka_common.h"
 
+#define SIM_MAX_STRING_LENGTH          1016            //!< Maximum size of a SIM/AKA['] string ((4 * 255) - 4).
 #define SIM_IV_SIZE                    16              //!< Length of the IV used when processing AT_ENCR.
 #define SIM_MAC_DIGEST_SIZE            16              //!< Length of MAC used to prevent packet modification.
 #define SIM_MAC_SIZE                   20              //!< Length of MAC used to prevent packet modification.