From: Bodo Möller <bodo@openssl.org>
Date: Mon, 29 Mar 1999 16:07:36 +0000 (+0000)
Subject: Added comments to des_enc_{read,write} functions warning about their
X-Git-Tag: OpenSSL_0_9_3beta1~394
X-Git-Url: https://git.openssl.org/?p=openssl.git;a=commitdiff_plain;h=7c0f3d09b32ee1882ee309b660e82bc3077f42db;ds=sidebyside

Added comments to des_enc_{read,write} functions warning about their
cryptographic weakness (IV reuse).
---

diff --git a/crypto/des/enc_read.c b/crypto/des/enc_read.c
index 265e9ca36f..3e5ac09875 100644
--- a/crypto/des/enc_read.c
+++ b/crypto/des/enc_read.c
@@ -65,6 +65,25 @@
 /*extern int errno;*/
 int des_rw_mode=DES_PCBC_MODE;
 
+
+/*
+ * WARNINGS:
+ *
+ *  -  The data format used by des_enc_write() and des_enc_read()
+ *     has a cryptographic weakness: When asked to write more
+ *     than MAXWRITE bytes, des_enc_write will split the data
+ *     into several chunks that are all encrypted
+ *     using the same IV.  So don't use these functions unless you
+ *     are sure you know what you do (in which case you might
+ *     not want to use them anyway).
+ *
+ *  -  This code cannot handle non-blocking sockets.
+ *
+ *  -  This function uses an internal state and thus cannot be
+ *     used on multiple files.
+ */
+
+
 int des_enc_read(fd, buf, len, sched, iv)
 int fd;
 char *buf;
diff --git a/crypto/des/enc_writ.c b/crypto/des/enc_writ.c
index 96537ef584..d40dc273c0 100644
--- a/crypto/des/enc_writ.c
+++ b/crypto/des/enc_writ.c
@@ -62,6 +62,20 @@
 #include "cryptlib.h"
 #include "des_locl.h"
 
+/*
+ * WARNINGS:
+ *
+ *  -  The data format used by des_enc_write() and des_enc_read()
+ *     has a cryptographic weakness: When asked to write more
+ *     than MAXWRITE bytes, des_enc_write will split the data
+ *     into several chunks that are all encrypted
+ *     using the same IV.  So don't use these functions unless you
+ *     are sure you know what you do (in which case you might
+ *     not want to use them anyway).
+ *
+ *  -  This code cannot handle non-blocking sockets.
+ */
+
 int des_enc_write(fd, buf, len, sched, iv)
 int fd;
 const char *buf;