diff --git a/libc/decl/errno_values.h b/libc/decl/errno_values.h
index 00e15313..b8b4a38c 100644
--- a/libc/decl/errno_values.h
+++ b/libc/decl/errno_values.h
@@ -59,6 +59,7 @@
 #define ECONNRESET 67
 #define EADDRNOTAVAIL 68
 #define EISCONN 69
+#define EFAULT 70
 
 #define EOPNOTSUPP ENOTSUP
 
diff --git a/libc/strerror.cpp b/libc/strerror.cpp
index 46c950d2..84f9e36c 100644
--- a/libc/strerror.cpp
+++ b/libc/strerror.cpp
@@ -88,6 +88,7 @@ extern "C" const char* sortix_strerror(int errnum)
 	case ECONNRESET: return "Connection reset";
 	case EADDRNOTAVAIL: return "Address not available";
 	case EISCONN: return "Socket is connected";
+	case EFAULT: return "Bad address";
 	default: return "Unknown error condition";
 	}
 }