Apply upstream-recommended patch to fix bignum encoding for curve25519-sha256@libssh.org, fixing occasional key exchange failures.

1 files changed, 16 insertions, 1 deletions

diff --git a/compat.c b/compat.c
index 9d9fabef3..2709dc5cf 100644
--- a/compat.c
+++ b/compat.c
@@ -95,6 +95,9 @@ compat_datafellows(const char *version)
                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
                 { "OpenSSH_4*",         0 },
                 { "OpenSSH_5*",         SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
+                { "OpenSSH_6.6.1*",     SSH_NEW_OPENSSH},
+                { "OpenSSH_6.5*,"
+                  "OpenSSH_6.6*",       SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
                 { "OpenSSH*",           SSH_NEW_OPENSSH },
                 { "*MindTerm*",         0 },
                 { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
@@ -251,7 +254,6 @@ compat_cipher_proposal(char *cipher_prop)
         return cipher_prop;
 }
 
-
 char *
 compat_pkalg_proposal(char *pkalg_prop)
 {
@@ -265,3 +267,16 @@ compat_pkalg_proposal(char *pkalg_prop)
         return pkalg_prop;
 }
 
+char *
+compat_kex_proposal(char *kex_prop)
+{
+        if (!(datafellows & SSH_BUG_CURVE25519PAD))
+                return kex_prop;
+        debug2("%s: original KEX proposal: %s", __func__, kex_prop);
+        kex_prop = filter_proposal(kex_prop, "curve25519-sha256@libssh.org");
+        debug2("%s: compat KEX proposal: %s", __func__, kex_prop);
+        if (*kex_prop == '\0')
+                fatal("No supported key exchange algorithms found");
+        return kex_prop;
+}
+