From 3460c7dd68147d2a343893752ad9cd29d74f5def Mon Sep 17 00:00:00 2001 From: Greg Hudson Date: Mon, 19 Jul 2010 05:01:45 +0000 Subject: [PATCH] Allow Microsoft HMAC-MD5 checksum types to use non-RC4 keys In PAC signatures, the hmac-md5 checksum type can be used with AES keys. Make this work by removing the enc field from the hmac-md5 and md5-hmac checksum types, and adding a check in krb5int_hmacmd5_checksum() for a null key or a key which is longer than the hash block size (64 bytes for MD5). The checksum algorithm only uses the key bits; it does invoke the cipher. The checksum type names are kind of wrong, but we'll leave them alone for compatibility. The descriptions are updated. ticket: 6751 target_version: 1.8.3 tags: pullup git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@24191 dc483132-0cff-0310-8789-dd5450dbe970 --- src/lib/crypto/krb/checksum/hmac_md5.c | 2 ++ src/lib/crypto/krb/cksumtypes.c | 8 ++++---- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/src/lib/crypto/krb/checksum/hmac_md5.c b/src/lib/crypto/krb/checksum/hmac_md5.c index 1dc05ea8b..48129075d 100644 --- a/src/lib/crypto/krb/checksum/hmac_md5.c +++ b/src/lib/crypto/krb/checksum/hmac_md5.c @@ -48,6 +48,8 @@ krb5_error_code krb5int_hmacmd5_checksum(const struct krb5_cksumtypes *ctp, krb5_data ds = empty_data(), hashval = empty_data(); char t[4]; + if (key == NULL || key->keyblock.length > ctp->hash->blocksize) + return KRB5_BAD_ENCTYPE; if (ctp->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR) { /* Compute HMAC(key, "signaturekey\0") to get the signing key ks. */ ret = alloc_data(&ds, key->keyblock.length); diff --git a/src/lib/crypto/krb/cksumtypes.c b/src/lib/crypto/krb/cksumtypes.c index 74fd158ab..6e16b4ea8 100644 --- a/src/lib/crypto/krb/cksumtypes.c +++ b/src/lib/crypto/krb/cksumtypes.c @@ -82,8 +82,8 @@ const struct krb5_cksumtypes krb5int_cksumtypes_list[] = { { CKSUMTYPE_HMAC_MD5_ARCFOUR, "hmac-md5-rc4", { "hmac-md5-enc", "hmac-md5-earcfour" }, - "Microsoft HMAC MD5 (RC4 key)", - &krb5int_enc_arcfour, &krb5int_hash_md5, + "Microsoft HMAC MD5", + NULL, &krb5int_hash_md5, krb5int_hmacmd5_checksum, NULL, 16, 16, 0 }, @@ -100,8 +100,8 @@ const struct krb5_cksumtypes krb5int_cksumtypes_list[] = { 20, 12, 0 }, { CKSUMTYPE_MD5_HMAC_ARCFOUR, - "md5-hmac-rc4", { 0 }, "Microsoft MD5 HMAC (RC4 key)", - &krb5int_enc_arcfour, &krb5int_hash_md5, + "md5-hmac-rc4", { 0 }, "Microsoft MD5 HMAC", + NULL, &krb5int_hash_md5, krb5int_hmacmd5_checksum, NULL, 16, 16, 0 }, }; -- 2.26.2