krb5 commit: Kill TCP connections if getsockname fails

[Greg Hudson]

https://github.com/krb5/krb5/commit/342d51e9e3ee0e35addf6a64d177730d980755d7
commit 342d51e9e3ee0e35addf6a64d177730d980755d7
Author: Andreas Schneider <asn at samba.org>
Date:   Tue May 30 09:50:10 2017 +0200

    Kill TCP connections if getsockname fails
    
    In net-server.c:process_tcp_connection_read(), we don't expect
    getsockname() to fail under ordinary circumstances, so instead of
    passing a null local address to dispatch(), just error out.  Simplify
    schpw.c:dispatch() by assuming a non-null local_saddr.
    
    [ghudson at mit.edu: simplified schpw.c:dispatch(); rewrote commit
    message]

 src/kadmin/server/schpw.c     |   16 +++-------------
 src/lib/apputils/net-server.c |   10 ++++++----
 2 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/src/kadmin/server/schpw.c b/src/kadmin/server/schpw.c
index 2823057..d89d246 100644
--- a/src/kadmin/server/schpw.c
+++ b/src/kadmin/server/schpw.c
@@ -444,20 +444,11 @@ dispatch(void *handle, struct sockaddr *local_saddr,
     krb5_keytab kt = NULL;
     kadm5_server_handle_t server_handle = (kadm5_server_handle_t)handle;
     krb5_fulladdr local_faddr;
-    krb5_address **local_kaddrs = NULL, local_kaddr_buf;
+    krb5_address local_kaddr_buf;
     krb5_data *response = NULL;
 
-    if (local_saddr == NULL) {
-        ret = krb5_os_localaddr(server_handle->context, &local_kaddrs);
-        if (ret != 0)
-            goto egress;
-
-        local_faddr.address = local_kaddrs[0];
-        local_faddr.port = 0;
-    } else {
-        local_faddr.address = &local_kaddr_buf;
-        init_addr(&local_faddr, local_saddr);
-    }
+    local_faddr.address = &local_kaddr_buf;
+    init_addr(&local_faddr, local_saddr);
 
     ret = krb5_kt_resolve(server_handle->context, "KDB:", &kt);
     if (ret != 0) {
@@ -481,7 +472,6 @@ dispatch(void *handle, struct sockaddr *local_saddr,
 egress:
     if (ret)
         krb5_free_data(server_handle->context, response);
-    krb5_free_addresses(server_handle->context, local_kaddrs);
     krb5_kt_close(server_handle->context, kt);
     (*respond)(arg, ret, ret == 0 ? response : NULL);
 }
diff --git a/src/lib/apputils/net-server.c b/src/lib/apputils/net-server.c
index f0b7a38..ee3d743 100644
--- a/src/lib/apputils/net-server.c
+++ b/src/lib/apputils/net-server.c
@@ -1329,7 +1329,6 @@ process_tcp_connection_read(verto_ctx *ctx, verto_ev *ev)
     } else {
         /* msglen known. */
         socklen_t local_saddrlen = sizeof(struct sockaddr_storage);
-        struct sockaddr *local_saddrp = NULL;
 
         len = conn->msglen - (conn->offset - 4);
         nread = SOCKET_READ(verto_get_fd(ev),
@@ -1351,10 +1350,13 @@ process_tcp_connection_read(verto_ctx *ctx, verto_ev *ev)
         state->request.data = conn->buffer + 4;
 
         if (getsockname(verto_get_fd(ev), ss2sa(&state->local_saddr),
-                        &local_saddrlen) == 0)
-            local_saddrp = ss2sa(&state->local_saddr);
+                        &local_saddrlen) < 0) {
+            krb5_klog_syslog(LOG_ERR, _("getsockname failed: %s"),
+                             error_message(errno));
+            goto kill_tcp_connection;
+        }
 
-        dispatch(state->conn->handle, local_saddrp, &conn->faddr,
+        dispatch(state->conn->handle, ss2sa(&state->local_saddr), &conn->faddr,
                  &state->request, 1, ctx, process_tcp_response, state);
     }