Commit 245a7eee authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

recalculate DSA signature if r or s is zero (FIPS 186-3 requirement)

parent 6e0375d5

crypto/dsa/dsa.h

+1 −0
Original line number Diff line number Diff line
@@ -299,6 +299,7 @@ void ERR_load_DSA_strings(void); 
#define DSA_R_INVALID_DIGEST_TYPE			 106

#define DSA_R_MISSING_PARAMETERS			 101

#define DSA_R_MODULUS_TOO_LARGE				 103

#define DSA_R_NEED_NEW_SETUP_VALUES			 110

#define DSA_R_NO_PARAMETERS_SET				 107

#define DSA_R_PARAMETER_ENCODING_ERROR			 105

crypto/dsa/dsa_err.c

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ static ERR_STRING_DATA DSA_str_reasons[]= 
{ERR_REASON(DSA_R_INVALID_DIGEST_TYPE)   ,"invalid digest type"},

{ERR_REASON(DSA_R_MISSING_PARAMETERS)    ,"missing parameters"},

{ERR_REASON(DSA_R_MODULUS_TOO_LARGE)     ,"modulus too large"},

{ERR_REASON(DSA_R_NEED_NEW_SETUP_VALUES) ,"need new setup values"},

{ERR_REASON(DSA_R_NO_PARAMETERS_SET)     ,"no parameters set"},

{ERR_REASON(DSA_R_PARAMETER_ENCODING_ERROR),"parameter encoding error"},

{0,NULL}

crypto/dsa/dsa_ossl.c

+15 −1
Original line number Diff line number Diff line
@@ -136,6 +136,7 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) 
	BN_CTX *ctx=NULL;

	int reason=ERR_R_BN_LIB;

	DSA_SIG *ret=NULL;

	int noredo = 0;



	BN_init(&m);

	BN_init(&xr);
@@ -159,7 +160,7 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) 


	ctx=BN_CTX_new();

	if (ctx == NULL) goto err;



redo:

	if ((dsa->kinv == NULL) || (dsa->r == NULL))

		{

		if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err;
@@ -170,6 +171,7 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) 
		dsa->kinv=NULL;

		r=dsa->r;

		dsa->r=NULL;

		noredo = 1;

		}
@@ -190,6 +192,18 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) 


	ret=DSA_SIG_new();

	if (ret == NULL) goto err;

	/* Redo if r or s is zero as required by FIPS 186-3: this is

	 * very unlikely.

	 */

	if (BN_is_zero(r) || BN_is_zero(s))

		{

		if (noredo)

			{

			reason = DSA_R_NEED_NEW_SETUP_VALUES;

			goto err;

			}

		goto redo;

		}

	ret->r = r;

	ret->s = s;