From 596212e71abf33b30608348b782c093dace83110 Mon Sep 17 00:00:00 2001 From: Werner Koch Date: Wed, 17 Jun 2020 14:27:12 +0200 Subject: [PATCH] sm: Support verification of nistp521 signatures. * sm/certcheck.c (do_encode_md): Take care of nistp521. -- That curve is a bit odd in that it does not match a common hash digest length. We fix that here for just this case instead of writing more general code to support all allowed cases (i.e. hash shorter than Q). Signed-off-by: Werner Koch --- sm/certcheck.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/sm/certcheck.c b/sm/certcheck.c index 3604ac788..cf9495a58 100644 --- a/sm/certcheck.c +++ b/sm/certcheck.c @@ -77,12 +77,15 @@ do_encode_md (gcry_md_hd_t md, int algo, int pkalgo, unsigned int nbits, if (pkalgo == GCRY_PK_DSA || pkalgo == GCRY_PK_ECC) { - unsigned int qbits; + unsigned int qbits0, qbits; if ( pkalgo == GCRY_PK_ECC ) - qbits = gcry_pk_get_nbits (pkey); + { + qbits0 = gcry_pk_get_nbits (pkey); + qbits = qbits0 == 521? 512 : qbits; + } else - qbits = get_dsa_qbits (pkey); + qbits0 = qbits = get_dsa_qbits (pkey); if ( (qbits%8) ) { @@ -99,7 +102,7 @@ do_encode_md (gcry_md_hd_t md, int algo, int pkalgo, unsigned int nbits, if (qbits < 160) { log_error (_("%s key uses an unsafe (%u bit) hash\n"), - gcry_pk_algo_name (pkalgo), qbits); + gcry_pk_algo_name (pkalgo), qbits0); return gpg_error (GPG_ERR_INTERNAL); } @@ -110,7 +113,7 @@ do_encode_md (gcry_md_hd_t md, int algo, int pkalgo, unsigned int nbits, { log_error (_("a %u bit hash is not valid for a %u bit %s key\n"), (unsigned int)nframe*8, - gcry_pk_get_nbits (pkey), + qbits0, gcry_pk_algo_name (pkalgo)); /* FIXME: we need to check the requirements for ECDSA. */ if (nframe < 20 || pkalgo == GCRY_PK_DSA )