From af951c2dba5b25e3a479062065a7748189793340 Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Thu, 8 Nov 2018 11:27:05 -0500
Subject: [PATCH] Catch bad private keys early on.
---
rsa-sign.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/rsa-sign.c b/rsa-sign.c
index 48323527..332420fe 100644
--- a/rsa-sign.c
+++ b/rsa-sign.c
@@ -69,7 +69,13 @@ int
rsa_private_key_prepare(struct rsa_private_key *key)
{
mpz_t n;
-
+
+ /* A key is invalid if the sizes of q and c are smaller than
+ * the size of n, we rely on that property in calculations so
+ * fail early if that happens. */
+ if (mpz_size (key->q) + mpz_size (key->c) < mpz_size(key->p))
+ return 0;
+
/* The size of the product is the sum of the sizes of the factors,
* or sometimes one less. It's possible but tricky to compute the
* size without computing the full product. */
@@ -80,7 +86,7 @@ rsa_private_key_prepare(struct rsa_private_key *key)
key->size = _rsa_check_size(n);
mpz_clear(n);
-
+
return (key->size > 0);
}
--
GitLab