From e7266b788278f019ad15d2d2fe518401e98c5645 Mon Sep 17 00:00:00 2001
From: Robbie Harwood <rharwood@redhat.com>
Date: Tue, 31 Jul 2018 13:47:26 -0400
Subject: [PATCH] In FIPS mode, add plaintext fallback for RC4 usages and taint
---
src/lib/krad/attr.c | 38 ++++++++++++++++++++++++++++----------
src/lib/krad/attrset.c | 5 +++--
src/lib/krad/internal.h | 13 +++++++++++--
src/lib/krad/packet.c | 18 +++++++++---------
src/lib/krad/remote.c | 10 ++++++++--
src/lib/krad/t_attr.c | 3 ++-
src/lib/krad/t_attrset.c | 4 +++-
7 files changed, 64 insertions(+), 27 deletions(-)
diff --git a/src/lib/krad/attr.c b/src/lib/krad/attr.c
index 9c13d9d75..f96153e2e 100644
--- a/src/lib/krad/attr.c
+++ b/src/lib/krad/attr.c
@@ -38,7 +38,8 @@
typedef krb5_error_code
(*attribute_transform_fn)(krb5_context ctx, const char *secret,
const unsigned char *auth, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *is_fips);
typedef struct {
const char *name;
@@ -51,12 +52,14 @@ typedef struct {
static krb5_error_code
user_password_encode(krb5_context ctx, const char *secret,
const unsigned char *auth, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *is_fips);
static krb5_error_code
user_password_decode(krb5_context ctx, const char *secret,
const unsigned char *auth, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *ignored);
static const attribute_record attributes[UCHAR_MAX] = {
{"User-Name", 1, MAX_ATTRSIZE, NULL, NULL},
@@ -128,7 +131,8 @@ static const attribute_record attributes[UCHAR_MAX] = {
static krb5_error_code
user_password_encode(krb5_context ctx, const char *secret,
const unsigned char *auth, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *is_fips)
{
const unsigned char *indx;
krb5_error_code retval;
@@ -156,7 +160,12 @@ user_password_encode(krb5_context ctx, const char *secret,
retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &tmp,
&sum);
- if (retval != 0) {
+ if (retval == ENOMEM) {
+ /* I'm Linux, so we know this is a FIPS failure. RSA_MD5 doesn't
+ * provide security so let's move on. */
+ *is_fips = TRUE;
+ sum.contents = calloc(1, BLOCKSIZE);
+ } else if (retval != 0) {
zap(tmp.data, tmp.length);
zap(outbuf, len);
krb5_free_data_contents(ctx, &tmp);
@@ -180,7 +189,8 @@ user_password_encode(krb5_context ctx, const char *secret,
static krb5_error_code
user_password_decode(krb5_context ctx, const char *secret,
const unsigned char *auth, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *is_fips)
{
const unsigned char *indx;
krb5_error_code retval;
@@ -206,7 +216,12 @@ user_password_decode(krb5_context ctx, const char *secret,
retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0,
&tmp, &sum);
- if (retval != 0) {
+ if (retval == ENOMEM) {
+ /* I'm Linux, so we know this is a FIPS failure. Assume the
+ * other side is running locally and move on. */
+ *is_fips = TRUE;
+ sum.contents = calloc(1, BLOCKSIZE);
+ } else if (retval != 0) {
zap(tmp.data, tmp.length);
zap(outbuf, in->length);
krb5_free_data_contents(ctx, &tmp);
@@ -248,7 +263,7 @@ krb5_error_code
kr_attr_encode(krb5_context ctx, const char *secret,
const unsigned char *auth, krad_attr type,
const krb5_data *in, unsigned char outbuf[MAX_ATTRSIZE],
- size_t *outlen)
+ size_t *outlen, krb5_boolean *is_fips)
{
krb5_error_code retval;
@@ -265,7 +280,8 @@ kr_attr_encode(krb5_context ctx, const char *secret,
return 0;
}
- return attributes[type - 1].encode(ctx, secret, auth, in, outbuf, outlen);
+ return attributes[type - 1].encode(ctx, secret, auth, in, outbuf, outlen,
+ is_fips);
}
krb5_error_code
@@ -274,6 +290,7 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen)
{
krb5_error_code retval;
+ krb5_boolean ignored;
retval = kr_attr_valid(type, in);
if (retval != 0)
@@ -288,7 +305,8 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
return 0;
}
- return attributes[type - 1].decode(ctx, secret, auth, in, outbuf, outlen);
+ return attributes[type - 1].decode(ctx, secret, auth, in, outbuf, outlen,
+ &ignored);
}
krad_attr
diff --git a/src/lib/krad/attrset.c b/src/lib/krad/attrset.c
index 03c613716..d89982a13 100644
--- a/src/lib/krad/attrset.c
+++ b/src/lib/krad/attrset.c
@@ -167,7 +167,8 @@ krad_attrset_copy(const krad_attrset *set, krad_attrset **copy)
krb5_error_code
kr_attrset_encode(const krad_attrset *set, const char *secret,
const unsigned char *auth,
- unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen)
+ unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen,
+ krb5_boolean *is_fips)
{
unsigned char buffer[MAX_ATTRSIZE];
krb5_error_code retval;
@@ -181,7 +182,7 @@ kr_attrset_encode(const krad_attrset *set, const char *secret,
K5_TAILQ_FOREACH(a, &set->list, list) {
retval = kr_attr_encode(set->ctx, secret, auth, a->type, &a->attr,
- buffer, &attrlen);
+ buffer, &attrlen, is_fips);
if (retval != 0)
return retval;
diff --git a/src/lib/krad/internal.h b/src/lib/krad/internal.h
index 996a89372..a53ce31ce 100644
--- a/src/lib/krad/internal.h
+++ b/src/lib/krad/internal.h
@@ -49,6 +49,13 @@
typedef struct krad_remote_st krad_remote;
+struct krad_packet_st {
+ char buffer[KRAD_PACKET_SIZE_MAX];
+ krad_attrset *attrset;
+ krb5_data pkt;
+ krb5_boolean is_fips;
+};
+
/* Validate constraints of an attribute. */
krb5_error_code
kr_attr_valid(krad_attr type, const krb5_data *data);
@@ -57,7 +64,8 @@ kr_attr_valid(krad_attr type, const krb5_data *data);
krb5_error_code
kr_attr_encode(krb5_context ctx, const char *secret, const unsigned char *auth,
krad_attr type, const krb5_data *in,
- unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen);
+ unsigned char outbuf[MAX_ATTRSIZE], size_t *outlen,
+ krb5_boolean *is_fips);
/* Decode an attribute. */
krb5_error_code
@@ -69,7 +77,8 @@ kr_attr_decode(krb5_context ctx, const char *secret, const unsigned char *auth,
krb5_error_code
kr_attrset_encode(const krad_attrset *set, const char *secret,
const unsigned char *auth,
- unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen);
+ unsigned char outbuf[MAX_ATTRSETSIZE], size_t *outlen,
+ krb5_boolean *is_fips);
/* Decode attributes from a buffer. */
krb5_error_code
diff --git a/src/lib/krad/packet.c b/src/lib/krad/packet.c
index c597174b6..2fbf0ee1e 100644
--- a/src/lib/krad/packet.c
+++ b/src/lib/krad/packet.c
@@ -53,12 +53,6 @@ typedef unsigned char uchar;
#define pkt_auth(p) ((uchar *)offset(&(p)->pkt, OFFSET_AUTH))
#define pkt_attr(p) ((unsigned char *)offset(&(p)->pkt, OFFSET_ATTR))
-struct krad_packet_st {
- char buffer[KRAD_PACKET_SIZE_MAX];
- krad_attrset *attrset;
- krb5_data pkt;
-};
-
typedef struct {
uchar x[(UCHAR_MAX + 1) / 8];
} idmap;
@@ -190,7 +184,11 @@ auth_generate_response(krb5_context ctx, const char *secret,
retval = krb5_c_make_checksum(ctx, CKSUMTYPE_RSA_MD5, NULL, 0, &data,
&hash);
free(data.data);
- if (retval != 0)
+ if (retval == ENOMEM) {
+ /* We're on Linux, so this is a FIPS failure, and this checksum
+ * does very little security-wise anyway, so don't taint. */
+ hash.contents = calloc(1, AUTH_FIELD_SIZE);
+ } else if (retval != 0)
return retval;
memcpy(rauth, hash.contents, AUTH_FIELD_SIZE);
@@ -276,7 +274,7 @@ krad_packet_new_request(krb5_context ctx, const char *secret, krad_code code,
/* Encode the attributes. */
retval = kr_attrset_encode(set, secret, pkt_auth(pkt), pkt_attr(pkt),
- &attrset_len);
+ &attrset_len, &pkt->is_fips);
if (retval != 0)
goto error;
@@ -314,7 +312,7 @@ krad_packet_new_response(krb5_context ctx, const char *secret, krad_code code,
/* Encode the attributes. */
retval = kr_attrset_encode(set, secret, pkt_auth(request), pkt_attr(pkt),
- &attrset_len);
+ &attrset_len, &pkt->is_fips);
if (retval != 0)
goto error;
@@ -451,6 +449,8 @@ krad_packet_decode_response(krb5_context ctx, const char *secret,
const krb5_data *
krad_packet_encode(const krad_packet *pkt)
{
+ if (pkt->is_fips)
+ return NULL;
return &pkt->pkt;
}
diff --git a/src/lib/krad/remote.c b/src/lib/krad/remote.c
index 437f7e91a..0f90443ce 100644
--- a/src/lib/krad/remote.c
+++ b/src/lib/krad/remote.c
@@ -263,7 +263,7 @@ on_io_write(krad_remote *rr)
request *r;
K5_TAILQ_FOREACH(r, &rr->list, list) {
- tmp = krad_packet_encode(r->request);
+ tmp = &r->request->pkt;
/* If the packet has already been sent, do nothing. */
if (r->sent == tmp->length)
@@ -359,7 +359,7 @@ on_io_read(krad_remote *rr)
if (req != NULL) {
K5_TAILQ_FOREACH(r, &rr->list, list) {
if (r->request == req &&
- r->sent == krad_packet_encode(req)->length) {
+ r->sent == req->pkt.length) {
request_finish(r, 0, rsp);
break;
}
@@ -455,6 +455,12 @@ kr_remote_send(krad_remote *rr, krad_code code, krad_attrset *attrs,
(krad_packet_iter_cb)iterator, &r, &tmp);
if (retval != 0)
goto error;
+ else if (tmp->is_fips && rr->info->ai_family != AF_LOCAL &&
+ rr->info->ai_family != AF_UNIX) {
+ /* This would expose cleartext passwords, so abort. */
+ retval = ESOCKTNOSUPPORT;
+ goto error;
+ }
K5_TAILQ_FOREACH(r, &rr->list, list) {
if (r->request == tmp) {
diff --git a/src/lib/krad/t_attr.c b/src/lib/krad/t_attr.c
index eb2a780c8..4d285ad9d 100644
--- a/src/lib/krad/t_attr.c
+++ b/src/lib/krad/t_attr.c
@@ -50,6 +50,7 @@ main()
const char *tmp;
krb5_data in;
size_t len;
+ krb5_boolean is_fips = FALSE;
noerror(krb5_init_context(&ctx));
@@ -73,7 +74,7 @@ main()
in = string2data((char *)decoded);
retval = kr_attr_encode(ctx, secret, auth,
krad_attr_name2num("User-Password"),
- &in, outbuf, &len);
+ &in, outbuf, &len, &is_fips);
insist(retval == 0);
insist(len == sizeof(encoded));
insist(memcmp(outbuf, encoded, len) == 0);
diff --git a/src/lib/krad/t_attrset.c b/src/lib/krad/t_attrset.c
index 7928335ca..0f9576253 100644
--- a/src/lib/krad/t_attrset.c
+++ b/src/lib/krad/t_attrset.c
@@ -49,6 +49,7 @@ main()
krb5_context ctx;
size_t len = 0, encode_len;
krb5_data tmp;
+ krb5_boolean is_fips = FALSE;
noerror(krb5_init_context(&ctx));
noerror(krad_attrset_new(ctx, &set));
@@ -62,7 +63,8 @@ main()
noerror(krad_attrset_add(set, krad_attr_name2num("User-Password"), &tmp));
/* Encode attrset. */
- noerror(kr_attrset_encode(set, "foo", auth, buffer, &encode_len));
+ noerror(kr_attrset_encode(set, "foo", auth, buffer, &encode_len,
+ &is_fips));
krad_attrset_free(set);
/* Manually encode User-Name. */