From 1b76fac5ae55d2d307f635af4775a7c9149c8551 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Fri, 11 Mar 2011 17:42:11 +0000
Subject: [PATCH] Check requested security strength in DRBG. Add function to
 retrieve the security strength.

---
 crypto/fips_err.h         |  1 +
 fips/fips.h               |  1 +
 fips/rand/fips_drbg_lib.c | 20 +++++++++++++++++++-
 fips/rand/fips_drbgvs.c   |  6 +++---
 fips/rand/fips_rand.h     |  3 ++-
 5 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/crypto/fips_err.h b/crypto/fips_err.h
index 8bde7e8712..07a13e208e 100644
--- a/crypto/fips_err.h
+++ b/crypto/fips_err.h
@@ -128,6 +128,7 @@ static ERR_STRING_DATA FIPS_str_reasons[]=
 {ERR_REASON(FIPS_R_FIPS_SELFTEST_FAILED) ,"fips selftest failed"},
 {ERR_REASON(FIPS_R_GENERATE_ERROR)       ,"generate error"},
 {ERR_REASON(FIPS_R_INSTANTIATE_ERROR)    ,"instantiate error"},
+{ERR_REASON(FIPS_R_INSUFFICIENT_SECURITY_STRENGTH),"insufficient security strength"},
 {ERR_REASON(FIPS_R_INVALID_KEY_LENGTH)   ,"invalid key length"},
 {ERR_REASON(FIPS_R_IN_ERROR_STATE)       ,"in error state"},
 {ERR_REASON(FIPS_R_KEY_TOO_SHORT)        ,"key too short"},
diff --git a/fips/fips.h b/fips/fips.h
index fa4f68087d..ee144a1b2e 100644
--- a/fips/fips.h
+++ b/fips/fips.h
@@ -233,6 +233,7 @@ void ERR_load_FIPS_strings(void);
 #define FIPS_R_FIPS_SELFTEST_FAILED			 106
 #define FIPS_R_GENERATE_ERROR				 124
 #define FIPS_R_INSTANTIATE_ERROR			 125
+#define FIPS_R_INSUFFICIENT_SECURITY_STRENGTH		 132
 #define FIPS_R_INVALID_KEY_LENGTH			 109
 #define FIPS_R_IN_ERROR_STATE				 126
 #define FIPS_R_KEY_TOO_SHORT				 108
diff --git a/fips/rand/fips_drbg_lib.c b/fips/rand/fips_drbg_lib.c
index fd154c0346..1c8712e7a5 100644
--- a/fips/rand/fips_drbg_lib.c
+++ b/fips/rand/fips_drbg_lib.c
@@ -145,6 +145,12 @@ int FIPS_drbg_instantiate(DRBG_CTX *dctx,
 		goto end;
 		}
 
+	if (strength > dctx->strength)
+		{
+		r = FIPS_R_INSUFFICIENT_SECURITY_STRENGTH;
+		goto end;
+		}
+
 	dctx->status = DRBG_STATUS_ERROR;
 
 	entlen = dctx->get_entropy(dctx, dctx->entropy, dctx->strength,
@@ -261,7 +267,7 @@ int FIPS_drbg_reseed(DRBG_CTX *dctx,
 
 
 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
-			int prediction_resistance,
+			int strength, int prediction_resistance,
 			const unsigned char *adin, size_t adinlen)
 	{
 	int r = 0;
@@ -270,6 +276,13 @@ int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
 		r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;
 		return 0;
 		}
+
+	if (strength > dctx->strength)
+		{
+		r = FIPS_R_INSUFFICIENT_SECURITY_STRENGTH;
+		goto end;
+		}
+
 	if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance)
 		{
 		if (!FIPS_drbg_reseed(dctx, adin, adinlen))
@@ -351,3 +364,8 @@ size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)
 	{
 	return dctx->blocklength;
 	}
+
+int FIPS_drbg_get_strength(DRBG_CTX *dctx)
+	{
+	return dctx->strength;
+	}
diff --git a/fips/rand/fips_drbgvs.c b/fips/rand/fips_drbgvs.c
index 3f6a2a54e9..c60b80bf2f 100644
--- a/fips/rand/fips_drbgvs.c
+++ b/fips/rand/fips_drbgvs.c
@@ -269,7 +269,7 @@ int main(int argc,char **argv)
 			adin = hex2bin_m(value, &adinlen);
 			if (pr)
 				continue;
-			r = FIPS_drbg_generate(dctx, randout, randoutlen, 0,
+			r = FIPS_drbg_generate(dctx, randout, randoutlen, 0, 0,
 								adin, adinlen);
 			if (!r)
 				{
@@ -291,8 +291,8 @@ int main(int argc,char **argv)
 				t.ent = ent;
 				t.entlen = entlen;
 				r = FIPS_drbg_generate(dctx,
-							randout, randoutlen, 1,
-							adin, adinlen);
+							randout, randoutlen,
+							0, 1, adin, adinlen);
 				if (!r)
 					{
 					fprintf(stderr,
diff --git a/fips/rand/fips_rand.h b/fips/rand/fips_rand.h
index e9e2afbbaa..6a0b6729a7 100644
--- a/fips/rand/fips_rand.h
+++ b/fips/rand/fips_rand.h
@@ -80,7 +80,7 @@ int FIPS_drbg_instantiate(DRBG_CTX *dctx, int strength,
 				const unsigned char *pers, size_t perslen);
 int FIPS_drbg_reseed(DRBG_CTX *dctx, const unsigned char *adin, size_t adinlen);
 int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
-			int prediction_resistance,
+			int strength, int prediction_resistance,
 			const unsigned char *adin, size_t adinlen);
 
 int FIPS_drbg_uninstantiate(DRBG_CTX *dctx);
@@ -95,6 +95,7 @@ int FIPS_drbg_set_test_mode(DRBG_CTX *dctx,
 void *FIPS_drbg_get_app_data(DRBG_CTX *ctx);
 void FIPS_drbg_set_app_data(DRBG_CTX *ctx, void *app_data);
 size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx);
+int FIPS_drbg_get_strength(DRBG_CTX *dctx);
 
 #ifdef  __cplusplus
 }
-- 
2.25.1