From c0d5c673542b3d517c33fe1a9ab26bcda1a5a95f Mon Sep 17 00:00:00 2001 From: Werner Koch Date: Wed, 15 Apr 2020 11:05:41 +0200 Subject: sm,dirmngr: Restrict allowed parameters used with rsaPSS. * sm/certcheck.c (extract_pss_params): Check the used PSS params. * dirmngr/crlcache.c (finish_sig_check): Ditto. * dirmngr/validate.c (check_cert_sig): Ditto. -- GnuPG-bug-id: 4538 # ------------------------ >8 ------------------------ See https://www.metzdowd.com/pipermail/cryptography/2019-November/035449.html Signed-off-by: Werner Koch --- dirmngr/validate.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) (limited to 'dirmngr/validate.c') diff --git a/dirmngr/validate.c b/dirmngr/validate.c index 4f893b3ff..901c165ec 100644 --- a/dirmngr/validate.c +++ b/dirmngr/validate.c @@ -1014,7 +1014,31 @@ check_cert_sig (ksba_cert_t issuer_cert, ksba_cert_t cert) gcry_sexp_release (s_sig); return gpg_error (GPG_ERR_DIGEST_ALGO); } - /* log_debug ("PSS hash=%d saltlen=%u\n", algo, saltlen); */ + /* Add some restrictions; see ../sm/certcheck.c for details. */ + switch (algo) + { + case GCRY_MD_SHA1: + case GCRY_MD_SHA256: + case GCRY_MD_SHA384: + case GCRY_MD_SHA512: + case GCRY_MD_SHA3_256: + case GCRY_MD_SHA3_384: + case GCRY_MD_SHA3_512: + break; + default: + log_error ("PSS hash algorithm '%s' rejected\n", + gcry_md_algo_name (algo)); + gcry_sexp_release (s_sig); + return gpg_error (GPG_ERR_DIGEST_ALGO); + } + + if (gcry_md_get_algo_dlen (algo) != saltlen) + { + log_error ("PSS hash algorithm '%s' rejected due to salt length %u\n", + gcry_md_algo_name (algo), saltlen); + gcry_sexp_release (s_sig); + return gpg_error (GPG_ERR_DIGEST_ALGO); + } } algo_name = hash_algo_to_string (algo); -- cgit v1.2.3