From 75d507a4346840b6017e6180c752166406b69caa Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Mon, 13 Nov 2017 14:36:40 +0100
Subject: [PATCH] + crypto_core_ed25519_is_valid_point()

---
 dist-build/emscripten-symbols.def                 |  1 +
 src/libsodium/crypto_core/ed25519/core_ed25519.c  | 15 +++++++++++++++
 .../include/sodium/crypto_core_ed25519.h          |  3 +++
 3 files changed, 19 insertions(+)

diff --git a/dist-build/emscripten-symbols.def b/dist-build/emscripten-symbols.def
index 7ee99adb..9cbf04c2 100644
--- a/dist-build/emscripten-symbols.def
+++ b/dist-build/emscripten-symbols.def
@@ -145,6 +145,7 @@ _crypto_box_seedbytes 1 1
 _crypto_box_zerobytes 0 1
 _crypto_core_ed25519_add 0 1
 _crypto_core_ed25519_sub 0 1
+_crypto_core_ed25519_is_valid_point 0 1
 _crypto_core_hchacha20 1 1
 _crypto_core_hchacha20_constbytes 1 1
 _crypto_core_hchacha20_inputbytes 1 1
diff --git a/src/libsodium/crypto_core/ed25519/core_ed25519.c b/src/libsodium/crypto_core/ed25519/core_ed25519.c
index 5b675f1f..3f828812 100644
--- a/src/libsodium/crypto_core/ed25519/core_ed25519.c
+++ b/src/libsodium/crypto_core/ed25519/core_ed25519.c
@@ -3,6 +3,21 @@
 #include "private/common.h"
 #include "private/ed25519_ref10.h"
 
+int
+crypto_core_ed25519_is_valid_point(const unsigned char *p)
+{
+    ge25519_p3 p_p3;
+
+    if (ge25519_is_canonical(p) == 0 ||
+        ge25519_has_small_order(p) != 0 ||
+        ge25519_frombytes(&p_p3, p) != 0 ||
+        ge25519_is_on_curve(&p_p3) == 0 ||
+        ge25519_is_on_main_subgroup(&p_p3) == 0) {
+        return -1;
+    }
+    return 0;
+}
+
 int
 crypto_core_ed25519_add(unsigned char *r,
                         const unsigned char *p, const unsigned char *q)
diff --git a/src/libsodium/include/sodium/crypto_core_ed25519.h b/src/libsodium/include/sodium/crypto_core_ed25519.h
index 64043a61..af751cf2 100644
--- a/src/libsodium/include/sodium/crypto_core_ed25519.h
+++ b/src/libsodium/include/sodium/crypto_core_ed25519.h
@@ -8,6 +8,9 @@
 extern "C" {
 #endif
 
+SODIUM_EXPORT
+int crypto_core_ed25519_is_valid_point(const unsigned char *p);
+
 SODIUM_EXPORT
 int crypto_core_ed25519_add(unsigned char *r,
                             const unsigned char *p, const unsigned char *q);