feat(pki): add ssh_pki_ctx to ssh_session

The session struct now contains an ssh_pki_ctx struct as its member to allow for passing user configured pki options across many functions.
The ssh_options_set API has been extended to allow users to set this member.

Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Eshan Kelkar <eshankelkar@galorithm.com>

include/libssh/libssh.h

@@ -421,6 +421,7 @@ enum ssh_options_e {
     SSH_OPTIONS_CERTIFICATE,
     SSH_OPTIONS_PROXYJUMP,
     SSH_OPTIONS_PROXYJUMP_CB_LIST_APPEND,
+    SSH_OPTIONS_PKI_CONTEXT,
 };
 
 enum {

include/libssh/session.h

@@ -288,6 +288,10 @@ struct ssh_session_struct {
     /* counters */
     ssh_counter socket_counter;
     ssh_counter raw_counter;
+
+    /* PKI context structure containing various parameters to configure PKI
+     * operations */
+    struct ssh_pki_ctx_struct *pki_context;
 };
 
 /** @internal

src/options.c

@@ -258,6 +258,15 @@ int ssh_options_copy(ssh_session src, ssh_session *dest)
     new->common.log_verbosity       = src->common.log_verbosity;
     new->common.callbacks           = src->common.callbacks;
 
+    SSH_PKI_CTX_FREE(new->pki_context);
+    if (src->pki_context != NULL) {
+        new->pki_context = ssh_pki_ctx_dup(src->pki_context);
+        if (new->pki_context == NULL) {
+            ssh_free(new);
+            return -1;
+        }
+    }
+
     *dest = new;
 
     return 0;
@@ -629,6 +638,15 @@ int ssh_options_set_algo(ssh_session session,
  *                Set to "none" to disable connection sharing.
  *                (const char *)
  *
+ *              - SSH_OPTIONS_PKI_CONTEXT
+ *                Attach a previously created generic PKI context to the
+ *                session. This allows supplying per-session PKI
+ *                configuration options for PKI operations.
+ *                All fields from the user's context are copied to the session's
+ *                own context. The user retains ownership of the original
+ *                context and can free it after this call.
+ *                (ssh_pki_ctx)
+ *
  *
  * @param  value The value to set. This is a generic pointer and the
  *               datatype which is used should be set according to the
@@ -1358,6 +1376,20 @@ int ssh_options_set(ssh_session session, enum ssh_options_e type,
                 }
             }
             break;
+        case SSH_OPTIONS_PKI_CONTEXT:
+            if (value == NULL) {
+                ssh_set_error_invalid(session);
+                return -1;
+            }
+
+            SSH_PKI_CTX_FREE(session->pki_context);
+
+            session->pki_context = ssh_pki_ctx_dup((const ssh_pki_ctx)value);
+            if (session->pki_context == NULL) {
+                ssh_set_error_oom(session);
+                return -1;
+            }
+            break;
         default:
             ssh_set_error(session, SSH_REQUEST_DENIED, "Unknown ssh option %d", type);
             return -1;

src/session.c

@@ -108,6 +108,12 @@ ssh_session ssh_new(void)
         goto err;
     }
 
+    /* Initialise a default PKI context */
+    session->pki_context = ssh_pki_ctx_new();
+    if (session->pki_context == NULL) {
+        goto err;
+    }
+
     /* OPTIONS */
     session->opts.StrictHostKeyChecking = 1;
     session->opts.port = 22;
@@ -266,6 +272,8 @@ void ssh_free(ssh_session session)
 
   ssh_agent_free(session->agent);
 
+  SSH_PKI_CTX_FREE(session->pki_context);
+
   ssh_key_free(session->srv.rsa_key);
   session->srv.rsa_key = NULL;
   ssh_key_free(session->srv.ecdsa_key);