Fix assorted minor memory leaks.

All found by Coverity.

config.c

@@ -1429,7 +1429,7 @@ static void clipboard_selector_handler(union control *ctrl, dlgparam *dlg,
 #endif
         ) {
 #ifdef NAMED_CLIPBOARDS
-        const char *sval = dlg_editbox_get(ctrl, dlg);
+        char *sval = dlg_editbox_get(ctrl, dlg);
         int i;
 
         for (i = 0; i < lenof(options); i++)
@@ -1444,6 +1444,8 @@ static void clipboard_selector_handler(union control *ctrl, dlgparam *dlg,
                 sval++;
             conf_set_str(conf, strsetting, sval);
         }
+
+        sfree(sval);
 #else
         int index = dlg_listbox_index(ctrl, dlg);
         if (index >= 0) {

import.c

@@ -538,8 +538,10 @@ static ssh2_userkey *openssh_pem_read(
     strbuf *blob = strbuf_new_nm();
     int privptr = 0, publen;
 
-    if (!key)
+    if (!key) {
+        strbuf_free(blob);
         return NULL;
+    }
 
     if (key->encrypted) {
         unsigned char keybuf[32];

pageant.c

@@ -1290,6 +1290,9 @@ int pageant_add_keyfile(Filename *filename, const char *passphrase,
             if (resplen < 5 || response[4] != SSH_AGENT_SUCCESS) {
                 *retstr = dupstr("The already running Pageant "
                                  "refused to add the key.");
+                sfree(skey->comment);
+                ssh_key_free(skey->key);
+                sfree(skey);
                 sfree(response);
                 return PAGEANT_ACTION_FAILURE;
             }

sesschan.c

@@ -640,10 +640,10 @@ static void sesschan_notify_remote_exit(Seat *seat)
             sshfwd_send_exit_signal(
                 sess->c, signame, false, ptrlen_from_asciz(sigmsg));
 
-            sfree(sigmsg);
-
             got_signal = true;
         }
+
+        sfree(sigmsg);
     } else {
         int signum = pty_backend_exit_signum(sess->backend);
 

sshdss.c

@@ -72,8 +72,10 @@ static char *dss_cache_str(ssh_key *key)
     struct dss_key *dss = container_of(key, struct dss_key, sshk);
     strbuf *sb = strbuf_new();
 
-    if (!dss->p)
+    if (!dss->p) {
+        strbuf_free(sb);
         return NULL;
+    }
 
     append_hex_to_strbuf(sb, dss->p);
     append_hex_to_strbuf(sb, dss->q);

unix/uxagentsock.c

@@ -29,6 +29,7 @@ Socket *platform_make_agent_socket(
     if ((errw = make_dir_and_check_ours(socketdir)) != NULL) {
         *error = dupprintf("%s: %s\n", socketdir, errw);
         sfree(errw);
+        sfree(socketdir);
         return NULL;
     }
 

unix/uxsftp.c

@@ -490,6 +490,7 @@ static int ssh_sftp_do_select(bool include_stdin, bool no_fds_ok)
 
         if (i < 1 && !no_fds_ok && !toplevel_callback_pending()) {
             pollwrap_free(pw);
+            sfree(fdlist);
             return -1;                 /* doom */
         }