From: Tom Yu <tlyu@mit.edu>
Date: Thu, 9 Jun 2011 21:08:43 +0000 (+0000)
Subject: pull up r24750 from trunk
X-Git-Tag: krb5-1.9.2-beta1~22
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=4271a27907c9bc63528e1dae410a883d74b114b5;p=krb5.git

pull up r24750 from trunk

 ------------------------------------------------------------------------
 r24750 | ghudson | 2011-03-28 19:35:54 -0400 (Mon, 28 Mar 2011) | 11 lines

 ticket: 6886
 target_version: 1.9.1
 tags: pullup

 Remove the weak key checks from the builtin rc4 enc provider.  There
 is no standards support for avoiding RC4 weak keys, so rejecting them
 causes periodic failures.  Heimdal and Microsoft do not check for weak
 keys.  Attacks based on these weak keys are probably thwarted by the
 use of a confounder, and even if not, the reduction in work factor is
 not terribly significant for 128-bit keys.

ticket: 6886
version_fixed: 1.9.2
status: resolved

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-9@24951 dc483132-0cff-0310-8789-dd5450dbe970
---

diff --git a/src/lib/crypto/builtin/enc_provider/rc4.c b/src/lib/crypto/builtin/enc_provider/rc4.c
index a8e0721c9..1a9f8f9d0 100644
--- a/src/lib/crypto/builtin/enc_provider/rc4.c
+++ b/src/lib/crypto/builtin/enc_provider/rc4.c
@@ -39,16 +39,6 @@ static krb5_error_code k5_arcfour_init(ArcfourContext *ctx, const unsigned char
 static void k5_arcfour_crypt(ArcfourContext *ctx, unsigned char *dest,
                              const unsigned char *src, unsigned int len);
 
-static const unsigned char arcfour_weakkey1[] = {0x00, 0x00, 0xfd};
-static const unsigned char arcfour_weakkey2[] = {0x03, 0xfd, 0xfc};
-static const struct {
-    size_t length;
-    const unsigned char *data;
-} arcfour_weakkeys[] = {
-    { sizeof (arcfour_weakkey1), arcfour_weakkey1},
-    { sizeof (arcfour_weakkey2), arcfour_weakkey2},
-};
-
 static inline unsigned int k5_arcfour_byte(ArcfourContext * ctx)
 {
     unsigned int x;
@@ -90,13 +80,6 @@ k5_arcfour_init(ArcfourContext *ctx, const unsigned char *key,
     if (key_len != 16)
         return KRB5_BAD_MSIZE;     /*this is probably not the correct error code
                                      to return */
-    for (counter=0;
-         counter < sizeof(arcfour_weakkeys)/sizeof(arcfour_weakkeys[0]);
-         counter++)
-        if (!memcmp(key, arcfour_weakkeys[counter].data,
-                    arcfour_weakkeys[counter].length))
-            return KRB5DES_WEAK_KEY; /* most certainly not the correct error */
-
     state = &ctx->state[0];
     ctx->x = 0;
     ctx->y = 0;