Mercurial > dropbear

diff ecdsa.c @ 1855:35d504d59c05

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Implement server-side support for sk-ecdsa U2F-backed keys (#142) * Implement server-side support for sk-ecdsa U2F-backed keys * Fix out-of-bounds read on normal ecdsa-sha2-[identifier] keys * Fix one more potential out-of-bounds read * Check if nistp256 curve is used in sk-ecdsa-sha2- key It's the only allowed curve per PROTOCOL.u2f specification * Implement server-side support for sk-ed25519 FIDO2-backed keys * Keys with type sk-* make no sense as host keys, so they should be disabled * fix typo * Make sk-ecdsa call buf_ecdsa_verify This reduces code duplication, the SK code just handles the different message format. * Reduce sk specific code The application id can be stored in signkey, then we don't need to call sk-specific functions from svr-authpubkey * Remove debugging output, which causes compilation errors with DEBUG_TRACE disabled * Proper cleanup of sk_app Co-authored-by: Matt Johnston <[email protected]>
author egor-duda <egor-duda@users.noreply.github.com>
date Sat, 22 Jan 2022 16:53:04 +0300
parents d68d61e7056a
children
line wrap: on
line diff
--- a/ecdsa.c	Sat Jan 22 12:46:08 2022 +0800
+++ b/ecdsa.c	Sat Jan 22 16:53:04 2022 +0300
@@ -81,18 +81,25 @@
 	struct dropbear_ecc_curve **curve;
 	ecc_key *new_key = NULL;
 
-	/* string   "ecdsa-sha2-[identifier]" */
+	/* string   "ecdsa-sha2-[identifier]" or "[email protected]" */
 	key_ident = (unsigned char*)buf_getstring(buf, &key_ident_len);
 	/* string   "[identifier]" */
 	identifier = (unsigned char*)buf_getstring(buf, &identifier_len);
 
-	if (key_ident_len != identifier_len + strlen("ecdsa-sha2-")) {
-		TRACE(("Bad identifier lengths"))
-		goto out;
-	}
-	if (memcmp(&key_ident[strlen("ecdsa-sha2-")], identifier, identifier_len) != 0) {
-		TRACE(("mismatching identifiers"))
-		goto out;
+	if (strcmp (key_ident, "[email protected]") == 0) {
+		if (strcmp (identifier, "nistp256") != 0) {
+			TRACE(("mismatching identifiers"))
+			goto out;
+		}
+	} else {
+		if (key_ident_len != identifier_len + strlen ("ecdsa-sha2-")) {
+			TRACE(("Bad identifier lengths"))
+			goto out;
+		}
+		if (memcmp(&key_ident[strlen ("ecdsa-sha2-")], identifier, identifier_len) != 0) {
+			TRACE(("mismatching identifiers"))
+			goto out;
+		}
 	}
 
 	for (curve = dropbear_ecc_curves; *curve; curve++) {