From 667d9b75df86ec9ee1205f9101beb8dbbe4a00ae Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20=C5=A0tetiar?= Date: Wed, 1 Jul 2020 11:38:33 +0200 Subject: [PATCH] signkey: fix use of rsa-sha2-256 pubkeys MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 972d723484d8 ("split signkey_type and signature_type for RSA sha1 vs sha256") has added strict checking of pubkey algorithms which made keys with SHA-256 hashing algorithm unusable as they still reuse the `ssh-rsa` public key format. So fix this by disabling the check for rsa-sha2-256 pubkeys. Ref: https://tools.ietf.org/html/rfc8332#section-3 Fixes: 972d723484d8 ("split signkey_type and signature_type for RSA sha1 vs sha256") Signed-off-by: Petr Štetiar --- signkey.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/signkey.c +++ b/signkey.c @@ -652,10 +652,18 @@ int buf_verify(buffer * buf, sign_key *k sigtype = signature_type_from_name(type_name, type_name_len); m_free(type_name); - if (expect_sigtype != sigtype) { - dropbear_exit("Non-matching signing type"); + if (sigtype == DROPBEAR_SIGNATURE_NONE) { + dropbear_exit("No signature type"); } +#if DROPBEAR_RSA +#if DROPBEAR_RSA_SHA256 + if ((expect_sigtype != DROPBEAR_SIGNATURE_RSA_SHA256) && (expect_sigtype != sigtype)) { + dropbear_exit("Non-matching signing type"); + } +#endif +#endif + keytype = signkey_type_from_signature(sigtype); #if DROPBEAR_DSS if (keytype == DROPBEAR_SIGNKEY_DSS) {