From 210a2ccfdf485f22f5655b486019408c134e8fb7 Mon Sep 17 00:00:00 2001
From: Sylvain Rochet <gradator@gradator.net>
Date: Sat, 18 Apr 2015 18:51:45 +0200
Subject: [PATCH] PPP, MSCHAP, MPPE: shared identical mppe_sha1_pad* between
 MSCHAP and MPPE

---
 src/include/netif/ppp/mppe.h | 16 ++++++++++++++++
 src/netif/ppp/chap_ms.c      | 22 +++++++---------------
 src/netif/ppp/mppe.c         | 18 ++----------------
 3 files changed, 25 insertions(+), 31 deletions(-)

diff --git a/src/include/netif/ppp/mppe.h b/src/include/netif/ppp/mppe.h
index 44cfae78..2b9c4d4f 100644
--- a/src/include/netif/ppp/mppe.h
+++ b/src/include/netif/ppp/mppe.h
@@ -132,6 +132,22 @@
 	    opts |= MPPE_OPT_UNKNOWN;		\
     } while (/* CONSTCOND */ 0)
 
+/* Shared MPPE padding between MSCHAP and MPPE */
+#define SHA1_PAD_SIZE 40
+
+static const u8_t mppe_sha1_pad1[SHA1_PAD_SIZE] = {
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+static const u8_t mppe_sha1_pad2[SHA1_PAD_SIZE] = {
+  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
+};
+
 /*
  * State for an MPPE (de)compressor.
  */
diff --git a/src/netif/ppp/chap_ms.c b/src/netif/ppp/chap_ms.c
index 33ce8311..b1b5958f 100644
--- a/src/netif/ppp/chap_ms.c
+++ b/src/netif/ppp/chap_ms.c
@@ -93,6 +93,9 @@
 #include "netif/ppp/chap_ms.h"
 #include "netif/ppp/pppcrypt.h"
 #include "netif/ppp/magic.h"
+#if MPPE_SUPPORT
+#include "netif/ppp/mppe.h" /* For mppe_sha1_pad* */
+#endif /* MPPE_SUPPORT */
 
 #if LWIP_INCLUDED_POLARSSL_MD4
 #include "netif/ppp/polarssl/md4.h"
@@ -758,17 +761,6 @@ static void mppe_set_keys2(ppp_pcb *pcb, u_char PasswordHashHash[MD4_SIGNATURE_S
     u_char	MasterKey[SHA1_SIGNATURE_SIZE];	/* >= MPPE_MAX_KEY_LEN */
     u_char	Digest[SHA1_SIGNATURE_SIZE];	/* >= MPPE_MAX_KEY_LEN */
 
-    u_char SHApad1[40] =
-	{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
-    u_char SHApad2[40] =
-	{ 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-	  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-	  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-	  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2 };
-
     /* "This is the MPPE Master Key" */
     u_char Magic1[27] =
 	{ 0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
@@ -815,9 +807,9 @@ static void mppe_set_keys2(ppp_pcb *pcb, u_char PasswordHashHash[MD4_SIGNATURE_S
 	s = Magic2;
     sha1_starts(&sha1Context);
     sha1_update(&sha1Context, MasterKey, 16);
-    sha1_update(&sha1Context, SHApad1, sizeof(SHApad1));
+    sha1_update(&sha1Context, (unsigned char *)mppe_sha1_pad1, SHA1_PAD_SIZE);
     sha1_update(&sha1Context, s, 84);
-    sha1_update(&sha1Context, SHApad2, sizeof(SHApad2));
+    sha1_update(&sha1Context, (unsigned char *)mppe_sha1_pad2, SHA1_PAD_SIZE);
     sha1_finish(&sha1Context, Digest);
 
     MEMCPY(pcb->mppe_send_key, Digest, MPPE_MAX_KEY_LEN);
@@ -831,9 +823,9 @@ static void mppe_set_keys2(ppp_pcb *pcb, u_char PasswordHashHash[MD4_SIGNATURE_S
 	s = Magic3;
     sha1_starts(&sha1Context);
     sha1_update(&sha1Context, MasterKey, 16);
-    sha1_update(&sha1Context, SHApad1, sizeof(SHApad1));
+    sha1_update(&sha1Context, (unsigned char *)mppe_sha1_pad1, SHA1_PAD_SIZE);
     sha1_update(&sha1Context, s, 84);
-    sha1_update(&sha1Context, SHApad2, sizeof(SHApad2));
+    sha1_update(&sha1Context, (unsigned char *)mppe_sha1_pad2, SHA1_PAD_SIZE);
     sha1_finish(&sha1Context, Digest);
 
     MEMCPY(pcb->mppe_recv_key, Digest, MPPE_MAX_KEY_LEN);
diff --git a/src/netif/ppp/mppe.c b/src/netif/ppp/mppe.c
index 71826e13..d5a283bf 100644
--- a/src/netif/ppp/mppe.c
+++ b/src/netif/ppp/mppe.c
@@ -48,7 +48,6 @@
 #endif
 
 #define SHA1_SIGNATURE_SIZE 20
-#define SHA1_PAD_SIZE 40
 
 /* ppp_mppe_state.bits definitions */
 #define MPPE_BIT_A	0x80	/* Encryption table were (re)inititalized */
@@ -66,19 +65,6 @@
 #define MPPE_OVHD	2	/* MPPE overhead/packet */
 #define SANITY_MAX	1600	/* Max bogon factor we will tolerate */
 
-static const u8_t sha1_pad1[SHA1_PAD_SIZE] = {
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
-};
-static const u8_t sha1_pad2[SHA1_PAD_SIZE] = {
-  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
-  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
-};
-
 /*
  * Perform the MPPE rekey algorithm, from RFC 3078, sec. 7.3.
  * Well, not what's written there, but rather what they meant.
@@ -94,9 +80,9 @@ static void mppe_rekey(ppp_mppe_state * state, int initial_key)
 	 */
 	sha1_starts(&sha1);
 	sha1_update(&sha1, state->master_key, state->keylen);
-	sha1_update(&sha1, (unsigned char *)sha1_pad1, SHA1_PAD_SIZE);
+	sha1_update(&sha1, (unsigned char *)mppe_sha1_pad1, SHA1_PAD_SIZE);
 	sha1_update(&sha1, state->session_key, state->keylen);
-	sha1_update(&sha1, (unsigned char *)sha1_pad2, SHA1_PAD_SIZE);
+	sha1_update(&sha1, (unsigned char *)mppe_sha1_pad2, SHA1_PAD_SIZE);
 	sha1_finish(&sha1, sha1_digest);
 	MEMCPY(state->session_key, sha1_digest, state->keylen);