read back from libcrypto RAND when privdropping

makes certain libcrypto implementations cache a /dev/urandom fd
in preparation of sandboxing. Based on patch by Greg Hartman.

1 files changed, 6 insertions, 0 deletions

diff --git a/sshd.c b/sshd.c
index 65ef7e85..43d46508 100644
--- a/sshd.c
+++ b/sshd.c
@@ -624,6 +624,8 @@ privsep_preauth_child(void)
 	arc4random_buf(rnd, sizeof(rnd));
 #ifdef WITH_OPENSSL
 	RAND_seed(rnd, sizeof(rnd));
+	if ((RAND_bytes((u_char *)rnd, 1)) != 1)
+		fatal("%s: RAND_bytes failed", __func__);
 #endif
 	explicit_bzero(rnd, sizeof(rnd));
 
@@ -767,6 +769,8 @@ privsep_postauth(Authctxt *authctxt)
 	arc4random_buf(rnd, sizeof(rnd));
 #ifdef WITH_OPENSSL
 	RAND_seed(rnd, sizeof(rnd));
+	if ((RAND_bytes((u_char *)rnd, 1)) != 1)
+		fatal("%s: RAND_bytes failed", __func__);
 #endif
 	explicit_bzero(rnd, sizeof(rnd));
 
@@ -1436,6 +1440,8 @@ server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
 			arc4random_buf(rnd, sizeof(rnd));
 #ifdef WITH_OPENSSL
 			RAND_seed(rnd, sizeof(rnd));
+			if ((RAND_bytes((u_char *)rnd, 1)) != 1)
+				fatal("%s: RAND_bytes failed", __func__);
 #endif
 			explicit_bzero(rnd, sizeof(rnd));
 		}