[PATCH] Add support for 128-bit keys in RC2

[Peter Wu]

This patch adds support for decrypting (and encrypting) using 128-bit
keys using the RC2 algorithm.

Signed-off-by: Peter Wu <lekensteyn at gmail.com>
---
Hi,

First of all a disclaimer, I am not a cryptographer but a computer science
student. The purpose of this patch is to allow Wireshark to decrypt TLS packets
using the TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5 cipher suite (all cipher suites are
supported, except RC2[1]).

doc/gcrypt.texi was deliberately not updated as the help text might need other
notes like "this algorithm should not be used as it is insecure" besides "Both
40-bit and 128-bit keys are supported". I leave updating this document up to
you.

Regards,
Peter

 [1]: https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=9144
---
 cipher/cipher.c  |  2 ++
 cipher/rfc2268.c | 13 +++++++++++++
 src/cipher.h     |  1 +
 3 files changed, 16 insertions(+)

diff --git a/cipher/cipher.c b/cipher/cipher.c
index 6ddd58b..3b271d6 100644
--- a/cipher/cipher.c
+++ b/cipher/cipher.c
@@ -87,6 +87,8 @@ static struct cipher_table_entry
 #if USE_RFC2268
     { &_gcry_cipher_spec_rfc2268_40,
       &dummy_extra_spec,                  GCRY_CIPHER_RFC2268_40 },
+    { &_gcry_cipher_spec_rfc2268_128,
+      &dummy_extra_spec,                  GCRY_CIPHER_RFC2268_128 },
 #endif
 #if USE_SEED
     { &_gcry_cipher_spec_seed,
diff --git a/cipher/rfc2268.c b/cipher/rfc2268.c
index 130be9b..da0b9f4 100644
--- a/cipher/rfc2268.c
+++ b/cipher/rfc2268.c
@@ -351,8 +351,21 @@ static gcry_cipher_oid_spec_t oids_rfc2268_40[] =
     { NULL }
   };
 
+static gcry_cipher_oid_spec_t oids_rfc2268_128[] =
+  {
+    /* pbeWithSHAAnd128BitRC2_CBC */
+    { "1.2.840.113549.1.12.1.5", GCRY_CIPHER_MODE_CBC },
+    { NULL }
+  };
+
 gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_40 = {
   "RFC2268_40", NULL, oids_rfc2268_40,
   RFC2268_BLOCKSIZE, 40, sizeof(RFC2268_context),
   do_setkey, encrypt_block, decrypt_block
 };
+
+gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_128 = {
+  "RFC2268_128", NULL, oids_rfc2268_128,
+  RFC2268_BLOCKSIZE, 128, sizeof(RFC2268_context),
+  do_setkey, encrypt_block, decrypt_block
+};
diff --git a/src/cipher.h b/src/cipher.h
index 7791083..516154f 100644
--- a/src/cipher.h
+++ b/src/cipher.h
@@ -193,6 +193,7 @@ extern gcry_cipher_spec_t _gcry_cipher_spec_serpent128;
 extern gcry_cipher_spec_t _gcry_cipher_spec_serpent192;
 extern gcry_cipher_spec_t _gcry_cipher_spec_serpent256;
 extern gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_40;
+extern gcry_cipher_spec_t _gcry_cipher_spec_rfc2268_128;
 extern gcry_cipher_spec_t _gcry_cipher_spec_seed;
 extern gcry_cipher_spec_t _gcry_cipher_spec_camellia128;
 extern gcry_cipher_spec_t _gcry_cipher_spec_camellia192;
-- 
1.8.4