diff --git a/src/swtpm/ctrlchannel.c b/src/swtpm/ctrlchannel.c
index eac5acfc..11424488 100644
--- a/src/swtpm/ctrlchannel.c
+++ b/src/swtpm/ctrlchannel.c
@@ -349,7 +349,8 @@ static ssize_t ctrlchannel_recv_cmd(int fd,
                 msg->msg_iov[0].iov_len > buffer_len)
                 return -1;
         } else
-            n = read_eintr(fd, msg->msg_iov[0].iov_base + recvd, buffer_len - recvd);
+            n = read_eintr(fd, (char *)msg->msg_iov[0].iov_base + recvd,
+                           buffer_len - recvd);
         if (n <= 0)
             return n;
         recvd += n;
diff --git a/src/swtpm/utils.c b/src/swtpm/utils.c
index f8b875c7..d3d38a97 100644
--- a/src/swtpm/utils.c
+++ b/src/swtpm/utils.c
@@ -276,7 +276,7 @@ ssize_t write_full(int fd, const void *buffer, size_t buflen)
             return -1;
         }
         written += n;
-        buffer += n;
+        buffer = (const char *)buffer + n;
     }
     return written;
 }