When NSS is the crypto implementation, use the NSS PRNG. Avoids the

issue that Yarrow's entropy pools would be invalidated by a fork.

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/nss@24349 dc483132-0cff-0310-8789-dd5450dbe970

4 files changed, 82 insertions, 12 deletions

diff --git a/src/configure.in b/src/configure.in
index bd60b8e..c5bf4c4 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -134,6 +134,7 @@ openssl)
 nss)
   CRYPTO_IMPL_CFLAGS=`pkg-config --cflags nss`
   CRYPTO_IMPL_LIBS="-lnss3 $(pkg-config --libs nss-util)"
+  AC_DEFINE(CRYPTO_IMPL_NSS,1,[Define if crypto implementation is NSS])
   ;;
 *)
   AC_MSG_ERROR([Unknown crypto implementation $withval])
diff --git a/src/lib/crypto/crypto_tests/Makefile.in b/src/lib/crypto/crypto_tests/Makefile.in
index c92cc7e..cfab1b6 100644
--- a/src/lib/crypto/crypto_tests/Makefile.in
+++ b/src/lib/crypto/crypto_tests/Makefile.in
@@ -41,6 +41,9 @@ EXTRADEPSRCS=\
 # NOTE: The t_cksum known checksum values are primarily for regression
 # testing.  They are not derived a priori, but are known to produce
 # checksums that interoperate.
+#
+# We use the NSS PRNG when NSS is the crypto back end, so don't test
+# against the expected output for Yarrow.
 check-unix:: t_nfold t_encrypt t_prf t_prng t_hmac \
 		t_cksum4 t_cksum5 \
 		aes-test  \
@@ -48,8 +51,9 @@ check-unix:: t_nfold t_encrypt t_prf t_prng t_hmac \
 		t_crc t_cts t_short
 	$(RUN_SETUP) $(VALGRIND) ./t_nfold
 	$(RUN_SETUP) $(VALGRIND) ./t_encrypt
-	$(RUN_SETUP) $(VALGRIND) ./t_prng <$(srcdir)/t_prng.seed >t_prng.output && \
-	diff t_prng.output $(srcdir)/t_prng.expected
+	if [ @CRYPTO_IMPL@ != nss ]; then \
+	  $(RUN_SETUP) $(VALGRIND) ./t_prng <$(srcdir)/t_prng.seed >t_prng.output && \
+	  diff t_prng.output $(srcdir)/t_prng.expected; fi
 	$(RUN_SETUP) $(VALGRIND) ./t_hmac
 	$(RUN_SETUP) $(VALGRIND) ./t_prf <$(srcdir)/t_prf.in >t_prf.output
 	diff t_prf.output $(srcdir)/t_prf.expected
diff --git a/src/lib/crypto/krb/Makefile.in b/src/lib/crypto/krb/Makefile.in
index 9e01911..194b69c 100644
--- a/src/lib/crypto/krb/Makefile.in
+++ b/src/lib/crypto/krb/Makefile.in
@@ -8,7 +8,8 @@ LOCALINCLUDES = -I$(srcdir) -I$(srcdir)/../@CRYPTO_IMPL@/enc_provider -I$(srcdir
 		-I$(srcdir)/old -I$(srcdir)/raw -I$(srcdir)/yarrow 			\
 		-I$(srcdir)/../@CRYPTO_IMPL@/ -I$(srcdir)/../@CRYPTO_IMPL@/des		\
 		-I$(srcdir)/../@CRYPTO_IMPL@/aes -I$(srcdir)/arcfour 	\
-		-I$(srcdir)/../@CRYPTO_IMPL@/sha1 -I$(srcdir)/../@CRYPTO_IMPL@
+		-I$(srcdir)/../@CRYPTO_IMPL@/sha1 -I$(srcdir)/../@CRYPTO_IMPL@ \
+		@CRYPTO_IMPL_CFLAGS@
 PROG_LIBPATH=-L$(TOPLIBD)
 PROG_RPATH=$(KRB5_LIBDIR)
 DEFS=
diff --git a/src/lib/crypto/krb/prng.c b/src/lib/crypto/krb/prng.c
index ef32699..b9da3d5 100644
--- a/src/lib/crypto/krb/prng.c
+++ b/src/lib/crypto/krb/prng.c
@@ -29,11 +29,74 @@
 #include <assert.h>
 #include "k5-thread.h"
 
-#include "yarrow.h"
-static Yarrow_CTX y_ctx;
 #define yarrow_lock krb5int_yarrow_lock
 k5_mutex_t yarrow_lock = K5_MUTEX_PARTIAL_INITIALIZER;
 
+#ifdef CRYPTO_IMPL_NSS
+
+/*
+ * Using Yarrow with NSS is a bit problematic because the MD5 contexts it holds
+ * open for the entropy pools would be invalidated by a fork(), causing us to
+ * lose the entropy contained therein.
+ *
+ * Therefore, use the NSS PRNG if NSS is the crypto implementation.  Doing this
+ * via ifdefs here is temporary until we come up with better build logic for
+ * it.
+ */
+
+#include "../nss/nss_gen.h"
+#include <pk11pub.h>
+
+/* Gather 8K of OS entropy per call, enough to fill the additional data buffer
+ * for the built-in PRNG and trigger a reseed. */
+#define OS_ENTROPY_LEN 8192
+
+int krb5int_prng_init(void)
+{
+    return 0;
+}
+
+krb5_error_code KRB5_CALLCONV
+krb5_c_random_add_entropy(krb5_context context, unsigned int randsource,
+                          const krb5_data *data)
+{
+    krb5_error_code ret;
+
+    ret = k5_nss_init();
+    if (ret)
+        return ret;
+    if (PK11_RandomUpdate(data->data, data->length) != SECSuccess)
+        return k5_nss_map_last_error();
+    return 0;
+}
+
+krb5_error_code KRB5_CALLCONV
+krb5_c_random_make_octets(krb5_context context, krb5_data *data)
+{
+    krb5_error_code ret;
+
+    ret = k5_nss_init();
+    if (ret)
+        return ret;
+    if (PK11_GenerateRandom((unsigned char *)data->data,
+                            data->length) != SECSuccess)
+        return k5_nss_map_last_error();
+    return 0;
+}
+
+void
+krb5int_prng_cleanup (void)
+{
+}
+
+#else /* CRYPTO_IMPL_NSS */
+
+#include "yarrow.h"
+static Yarrow_CTX y_ctx;
+
+/* Gather enough OS entropy per call to trigger a Yarrow reseed. */
+#define OS_ENTROPY_LEN (YARROW_SLOW_THRESH/8)
+
 /* Helper function to estimate entropy based on sample length
  * and where it comes from.
  */
@@ -100,12 +163,6 @@ krb5_c_random_add_entropy(krb5_context context, unsigned int randsource,
 }
 
 krb5_error_code KRB5_CALLCONV
-krb5_c_random_seed(krb5_context context, krb5_data *data)
-{
-    return krb5_c_random_add_entropy(context, KRB5_C_RANDSOURCE_OLDAPI, data);
-}
-
-krb5_error_code KRB5_CALLCONV
 krb5_c_random_make_octets(krb5_context context, krb5_data *data)
 {
     int yerr;
@@ -127,6 +184,13 @@ krb5int_prng_cleanup (void)
     k5_mutex_destroy(&yarrow_lock);
 }
 
+#endif /* not CRYPTO_IMPL_NSS */
+
+krb5_error_code KRB5_CALLCONV
+krb5_c_random_seed(krb5_context context, krb5_data *data)
+{
+    return krb5_c_random_add_entropy(context, KRB5_C_RANDSOURCE_OLDAPI, data);
+}
 
 /*
  * Routines to get entropy from the OS.  For UNIX we try /dev/urandom
@@ -163,7 +227,7 @@ read_entropy_from_device(krb5_context context, const char *device)
     krb5_data data;
     struct stat sb;
     int fd;
-    unsigned char buf[YARROW_SLOW_THRESH/8], *bp;
+    unsigned char buf[OS_ENTROPY_LEN], *bp;
     int left;
 
     fd = open (device, O_RDONLY);