diff options
| author | Dr. Stephen Henson <steve@openssl.org> | 2011-01-25 16:01:29 +0000 |
|---|---|---|
| committer | Dr. Stephen Henson <steve@openssl.org> | 2011-01-25 16:01:29 +0000 |
| commit | 245a7eee177ccd7fd7986f86b67a4d59f5c4d6ad (patch) | |
| tree | 3acdbc11584c04330c8fd8ae3fac6146660f3666 /crypto/dsa/dsa_ossl.c | |
| parent | 6e0375d504c4bc8daec5a938c9d3232db3a72500 (diff) | |
recalculate DSA signature if r or s is zero (FIPS 186-3 requirement)
Diffstat (limited to 'crypto/dsa/dsa_ossl.c')
| -rw-r--r-- | crypto/dsa/dsa_ossl.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c index 1fb665ec57..1b416901b4 100644 --- a/crypto/dsa/dsa_ossl.c +++ b/crypto/dsa/dsa_ossl.c @@ -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; |