current/SOURCES/0003-Check-for-invalid-keys-with-even-p-in-dsa_sign.patch

From 544b4047de689519ab3e6ec55b776b95b3e264a9 Mon Sep 17 00:00:00 2001
From: Niels Möller <nisse@lysator.liu.se>
Date: Thu, 4 Aug 2016 10:22:26 +0200
Subject: [PATCH] Check for invalid keys, with even p, in dsa_sign.

---
 dsa-sign.c | 5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/dsa-sign.c b/dsa-sign.c
index 9d6bb18..b713743 100644
--- a/dsa-sign.c
+++ b/dsa-sign.c
@@ -56,6 +56,11 @@ dsa_sign(const struct dsa_params *params,
   mpz_t tmp;
   int res;
   
+  /* Check that p is odd, so that invalid keys don't result in a crash
+     inside mpz_powm_sec. */
+  if (mpz_even_p (params->p))
+    return 0;
+
   /* Select k, 0<k<q, randomly */
   mpz_init_set(tmp, params->q);
   mpz_sub_ui(tmp, tmp, 1);
--
libgit2 0.24.0

1	From 544b4047de689519ab3e6ec55b776b95b3e264a9 Mon Sep 17 00:00:00 2001
2	From: Niels Möller <nisse@lysator.liu.se>
3	Date: Thu, 4 Aug 2016 10:22:26 +0200
4	Subject: [PATCH] Check for invalid keys, with even p, in dsa_sign.
5
6	---
7	dsa-sign.c \| 5 +++++
8	1 files changed, 5 insertions(+), 0 deletions(-)
9
10	diff --git a/dsa-sign.c b/dsa-sign.c
11	index 9d6bb18..b713743 100644
12	--- a/dsa-sign.c
13	+++ b/dsa-sign.c
14	@@ -56,6 +56,11 @@ dsa_sign(const struct dsa_params *params,
15	mpz_t tmp;
16	int res;
17
18	+ /* Check that p is odd, so that invalid keys don't result in a crash
19	+ inside mpz_powm_sec. */
20	+ if (mpz_even_p (params->p))
21	+ return 0;
22	+
23	/* Select k, 0<k<q, randomly */
24	mpz_init_set(tmp, params->q);
25	mpz_sub_ui(tmp, tmp, 1);
26	--
27	libgit2 0.24.0
28