lib: Make crypt.c independent source file

The cryptography functions were in a C source that was directly
imported into dev.c, enabling ECDHE+AES256 symmetric key encryption on
flows. Now crypt.c is an independent source file with associated
crypt.h header, to prepare for security management and configuration
in the IRMd.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

4 files changed, 68 insertions, 54 deletions

diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index b75fd0e0..514d60d4 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -253,6 +253,7 @@ set(SOURCE_FILES_COMMON
   bitmap.c
   btree.c
   crc32.c
+  crypt.c
   hash.c
   list.c
   lockfile.c
diff --git a/src/lib/crypt.c b/src/lib/crypt.c
index 600ff3d1..c5d6101a 100644
--- a/src/lib/crypt.c
+++ b/src/lib/crypt.c
@@ -20,9 +20,19 @@
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., http://www.fsf.org/about/contact/.
  */
+#include <config.h>
+
+#include <ouroboros/crypt.h>
+#include <ouroboros/errno.h>
+
+#include <assert.h>
+#include <string.h>
 
 #ifdef HAVE_OPENSSL
 
+#include <ouroboros/hash.h>
+#include <ouroboros/random.h>
+
 #include <openssl/evp.h>
 #include <openssl/ec.h>
 #include <openssl/pem.h>
@@ -202,7 +212,8 @@ static int openssl_ecdh_derive(void *    pkp,
  * encryption context for each packet.
  */
 
-static int openssl_encrypt(struct flow *        f,
+static int openssl_encrypt(void *               ctx,
+                           uint8_t *            key,
                            struct shm_du_buff * sdb)
 {
         uint8_t * out;
@@ -226,24 +237,24 @@ static int openssl_encrypt(struct flow *        f,
         if (out == NULL)
                 goto fail_iv;
 
-        EVP_CIPHER_CTX_reset(f->ctx);
+        EVP_CIPHER_CTX_reset(ctx);
 
-        ret = EVP_EncryptInit_ex(f->ctx, EVP_aes_256_cbc(), NULL, f->key, iv);
+        ret = EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv);
         if (ret != 1)
                 goto fail_encrypt_init;
 
-        ret = EVP_EncryptUpdate(f->ctx, out, &tmp_sz, in, in_sz);
+        ret = EVP_EncryptUpdate(ctx, out, &tmp_sz, in, in_sz);
         if (ret != 1)
                 goto fail_encrypt;
 
         out_sz = tmp_sz;
-        ret =  EVP_EncryptFinal_ex(f->ctx, out + tmp_sz, &tmp_sz);
+        ret =  EVP_EncryptFinal_ex(ctx, out + tmp_sz, &tmp_sz);
         if (ret != 1)
                 goto fail_encrypt;
 
         out_sz += tmp_sz;
 
-        EVP_CIPHER_CTX_cleanup(f->ctx);
+        EVP_CIPHER_CTX_cleanup(ctx);
 
         assert(out_sz >= in_sz);
 
@@ -264,14 +275,15 @@ static int openssl_encrypt(struct flow *        f,
  fail_tail_alloc:
         shm_du_buff_head_release(sdb, IVSZ);
  fail_encrypt:
-        EVP_CIPHER_CTX_cleanup(f->ctx);
+        EVP_CIPHER_CTX_cleanup(ctx);
  fail_encrypt_init:
         free(out);
  fail_iv:
         return -ECRYPT;
 }
 
-static int openssl_decrypt(struct flow *        f,
+static int openssl_decrypt(void *               ctx,
+                           uint8_t *            key,
                            struct shm_du_buff * sdb)
 {
         uint8_t * in;
@@ -297,19 +309,19 @@ static int openssl_decrypt(struct flow *        f,
         if (out == NULL)
                 goto fail_malloc;
 
-        EVP_CIPHER_CTX_reset(f->ctx);
+        EVP_CIPHER_CTX_reset(ctx);
 
-        ret = EVP_DecryptInit_ex(f->ctx, EVP_aes_256_cbc(), NULL, f->key, iv);
+        ret = EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv);
         if (ret != 1)
                 goto fail_decrypt_init;
 
-        ret = EVP_DecryptUpdate(f->ctx, out, &tmp_sz, in, in_sz);
+        ret = EVP_DecryptUpdate(ctx, out, &tmp_sz, in, in_sz);
         if (ret != 1)
                 goto fail_decrypt;
 
         out_sz = tmp_sz;
 
-        ret = EVP_DecryptFinal_ex(f->ctx, out + tmp_sz, &tmp_sz);
+        ret = EVP_DecryptFinal_ex(ctx, out + tmp_sz, &tmp_sz);
         if (ret != 1)
                 goto fail_decrypt;
 
@@ -326,7 +338,7 @@ static int openssl_decrypt(struct flow *        f,
         return 0;
 
  fail_decrypt:
-        EVP_CIPHER_CTX_cleanup(f->ctx);
+        EVP_CIPHER_CTX_cleanup(ctx);
  fail_decrypt_init:
         free(out);
  fail_malloc:
@@ -350,8 +362,8 @@ static void openssl_crypt_fini(void * ctx)
 
 #endif /* HAVE_OPENSSL */
 
-static int crypt_dh_pkp_create(void **   pkp,
-                               uint8_t * pk)
+int crypt_dh_pkp_create(void **   pkp,
+                        uint8_t * pk)
 {
 #ifdef HAVE_OPENSSL
         assert(pkp != NULL);
@@ -361,14 +373,13 @@ static int crypt_dh_pkp_create(void **   pkp,
         (void) pkp;
         (void) pk;
 
-        memset(pk, 0, MSGBUFSZ);
         *pkp = NULL;
 
         return 0;
 #endif
 }
 
-static void crypt_dh_pkp_destroy(void * pkp)
+void crypt_dh_pkp_destroy(void * pkp)
 {
 #ifdef HAVE_OPENSSL
         openssl_ecdh_pkp_destroy(pkp);
@@ -378,10 +389,10 @@ static void crypt_dh_pkp_destroy(void * pkp)
 #endif
 }
 
-static int crypt_dh_derive(void *    pkp,
-                           uint8_t * pk,
-                           size_t    len,
-                           uint8_t * s)
+int crypt_dh_derive(void *    pkp,
+                    uint8_t * pk,
+                    size_t    len,
+                    uint8_t * s)
 {
 #ifdef HAVE_OPENSSL
         return openssl_ecdh_derive(pkp, pk, len, s);
@@ -396,50 +407,52 @@ static int crypt_dh_derive(void *    pkp,
 #endif
 }
 
-static int crypt_encrypt(struct flow *        f,
-                         struct shm_du_buff * sdb)
+int crypt_encrypt(struct crypt_info *  info,
+                  struct shm_du_buff * sdb)
 {
+        if (info->flags == 0)
+                return 0;
+
 #ifdef HAVE_OPENSSL
-        return openssl_encrypt(f, sdb);
+        return openssl_encrypt(info->ctx, info->key, sdb);
 #else
-        (void) f;
         (void) sdb;
 
         return 0;
 #endif
 }
 
-static int crypt_decrypt(struct flow *        f,
-                         struct shm_du_buff * sdb)
+int crypt_decrypt(struct crypt_info *  info,
+                  struct shm_du_buff * sdb)
 {
+        if (info->flags == 0)
+                return 0;
+
 #ifdef HAVE_OPENSSL
-        return openssl_decrypt(f, sdb);
+        return openssl_decrypt(info->ctx, info->key, sdb);
 #else
-        (void) f;
         (void) sdb;
 
         return -ECRYPT;
 #endif
 }
 
-static int crypt_init(void ** ctx)
+int crypt_init(struct crypt_info * info)
 {
 #ifdef HAVE_OPENSSL
-        return openssl_crypt_init(ctx);
+        return openssl_crypt_init(&info->ctx);
 #else
-        assert(ctx != NULL);
-        *ctx = NULL;
-
+        info->ctx = NULL;
         return 0;
 #endif
 }
 
-static void crypt_fini(void * ctx)
+void crypt_fini(struct crypt_info * info)
 {
 #ifdef HAVE_OPENSSL
-        openssl_crypt_fini(ctx);
+        openssl_crypt_fini(info->ctx);
 #else
-        assert(ctx == NULL);
-        (void) ctx;
+        (void) info;
+        assert(info->ctx == NULL);
 #endif
 }
diff --git a/src/lib/dev.c b/src/lib/dev.c
index ef909e1a..02f9d3f9 100644
--- a/src/lib/dev.c
+++ b/src/lib/dev.c
@@ -30,6 +30,7 @@
 
 #include <ouroboros/hash.h>
 #include <ouroboros/cacep.h>
+#include <ouroboros/crypt.h>
 #include <ouroboros/errno.h>
 #include <ouroboros/dev.h>
 #include <ouroboros/ipcp-dev.h>
@@ -71,7 +72,6 @@
 
 #define CRCLEN    (sizeof(uint32_t))
 #define SECMEMSZ  16384
-#define SYMMKEYSZ 32
 #define MSGBUFSZ  2048
 
 enum flow_state {
@@ -102,8 +102,7 @@ struct flow {
         qosspec_t             qs;
         ssize_t               part_idx;
 
-        void *                ctx;
-        uint8_t               key[SYMMKEYSZ];
+        struct crypt_info     crypt;
 
         pid_t                 pid;
 
@@ -256,7 +255,6 @@ static int proc_announce(char * prog)
         return ret;
 }
 
-#include "crypt.c"
 #include "frct.c"
 
 void * flow_tx(void * o)
@@ -429,8 +427,7 @@ static void flow_fini(int fd)
                 shm_flow_set_close(ai.flows[fd].set);
         }
 
-        if (ai.flows[fd].ctx != NULL)
-                crypt_fini(ai.flows[fd].ctx);
+        crypt_fini(&ai.flows[fd].crypt);
 
         list_del(&ai.flows[fd].next);
 
@@ -480,12 +477,15 @@ static int flow_init(int       flow_id,
         flow->snd_act  = now;
         flow->rcv_act  = now;
 
-        if (qs.cypher_s > 0) {
-                if (crypt_init(&flow->ctx) < 0)
-                        goto fail_ctx;
+        flow->crypt.flags = qs.cypher_s; /* TODO: remove cypher_s from qos */
 
-                memcpy(flow->key, s, SYMMKEYSZ);
-        }
+        if (flow->crypt.flags > 0)
+                memcpy(flow->crypt.key, s ,SYMMKEYSZ);
+        else
+                memset(flow->crypt.key, 0, SYMMKEYSZ);
+
+        if (crypt_init(&flow->crypt) < 0)
+                goto fail_crypt;
 
         assert(flow->frcti == NULL);
 
@@ -518,8 +518,8 @@ static int flow_init(int       flow_id,
  fail_flow_set_add:
         frcti_destroy(flow->frcti);
  fail_frcti:
-        crypt_fini(flow->ctx);
- fail_ctx:
+        crypt_fini(&flow->crypt);
+ fail_crypt:
         shm_flow_set_close(flow->set);
  fail_set:
         shm_rbuff_close(flow->tx_rb);
@@ -1299,7 +1299,7 @@ static int flow_tx_sdb(struct flow *        flow,
                 if (frcti_snd(flow->frcti, sdb) < 0)
                         goto enomem;
 
-                if (flow->qs.cypher_s > 0 && crypt_encrypt(flow, sdb) < 0)
+                if (crypt_encrypt(&flow->crypt, sdb) < 0)
                         goto enomem;
 
                 if (flow->qs.ber == 0 && add_crc(sdb) != 0)
@@ -1401,7 +1401,7 @@ static bool invalid_pkt(struct flow *        flow,
         if (flow->qs.ber == 0 && chk_crc(sdb) != 0)
                 return true;
 
-        if (flow->qs.cypher_s > 0 && crypt_decrypt(flow, sdb) < 0)
+        if (crypt_decrypt(&flow->crypt, sdb) < 0)
                 return true;
 
         return false;
diff --git a/src/lib/frct.c b/src/lib/frct.c
index a00b1acd..a3408481 100644
--- a/src/lib/frct.c
+++ b/src/lib/frct.c
@@ -261,7 +261,7 @@ static void __send_frct_pkt(int      fd,
 
         f = &ai.flows[fd];
 
-        if (f->qs.cypher_s > 0 && crypt_encrypt(f, sdb) < 0)
+        if (crypt_encrypt(&f->crypt, sdb) < 0)
                 goto fail;
 
 #ifdef RXM_BLOCKING