Based on:
https://github.com/paulusmack/ppp/commit/3c7b86229f7bd2600d74db14b1fe5b3896be3875

pppd: Use openssl for the DES instead of the libcrypt / glibc

It seems the latest glibc (in Fedora glibc-2.27.9000-12.fc29) dropped
libcrypt.  The libxcrypt standalone package can be used instead, but
it dropped the old setkey/encrypt API which ppp uses for DES.  There
is support for using openssl in pppcrypt.c, but it contains typos
preventing it from compiling and seems to be written for an ancient
openssl version.

This updates the code to use current openssl.

[paulus@ozlabs.org - wrote the commit description, fixed comment in
 Makefile.linux.]

Signed-off-by: Jaroslav Škarvada <jskarvad@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Index: pppd/Makefile.linux
===================================================================
--- ppp-2.4.7.orig/pppd/Makefile.linux
+++ ppp-2.4.7/pppd/Makefile.linux
@@ -35,10 +35,10 @@ endif
 #COPTS = -O2 -pipe -Wall -g
 LIBS ?=
 
-# Uncomment the next 2 lines to include support for Microsoft's
+# Uncomment the next line to include support for Microsoft's
 # MS-CHAP authentication protocol.  Also, edit plugins/radius/Makefile.linux.
 CHAPMS=y
-USE_CRYPT=y
+#USE_CRYPT=y
 # Don't use MSLANMAN unless you really know what you're doing.
 #MSLANMAN=y
 # Uncomment the next line to include support for MPPE.  CHAPMS (above) must
@@ -82,7 +82,7 @@ INCLUDE_DIRS= -I../include
 
 COMPILE_FLAGS= -DHAVE_PATHS_H -DIPX_CHANGE -DHAVE_MMAP
 
-CFLAGS= $(COMPILE_FLAGS) $(INCLUDE_DIRS) '-DDESTDIR="@DESTDIR@"'
+CFLAGS	+= $(COMPILE_FLAGS) $(INCLUDE_DIRS) '-DDESTDIR="@DESTDIR@"'
 
 ifdef CHAPMS
 CFLAGS   += -DCHAPMS=1
@@ -132,7 +132,7 @@ endif
 
 ifdef NEEDDES
 ifndef USE_CRYPT
-LIBS     += -ldes $(LIBS)
+LIBS     += -lcrypto
 else
 CFLAGS   += -DUSE_CRYPT=1
 endif
Index: pppd/pppcrypt.c
===================================================================
--- ppp-2.4.7.orig/pppd.orig/pppcrypt.c
+++ ppp-2.4.7/pppd/pppcrypt.c
@@ -64,7 +64,7 @@ u_char *des_key;	/* OUT 64 bit DES key w
 	des_key[7] = Get7Bits(key, 49);
 
 #ifndef USE_CRYPT
-	des_set_odd_parity((des_cblock *)des_key);
+	DES_set_odd_parity((DES_cblock *)des_key);
 #endif
 }
 
@@ -158,25 +158,25 @@ u_char *clear;	/* OUT 8 octets */
 }
 
 #else /* USE_CRYPT */
-static des_key_schedule	key_schedule;
+static DES_key_schedule	key_schedule;
 
 bool
 DesSetkey(key)
 u_char *key;
 {
-	des_cblock des_key;
+	DES_cblock des_key;
 	MakeKey(key, des_key);
-	des_set_key(&des_key, key_schedule);
+	DES_set_key(&des_key, &key_schedule);
 	return (1);
 }
 
 bool
-DesEncrypt(clear, key, cipher)
+DesEncrypt(clear, cipher)
 u_char *clear;	/* IN  8 octets */
 u_char *cipher;	/* OUT 8 octets */
 {
-	des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher,
-	    key_schedule, 1);
+	DES_ecb_encrypt((DES_cblock *)clear, (DES_cblock *)cipher,
+	    &key_schedule, 1);
 	return (1);
 }
 
@@ -185,8 +185,8 @@ DesDecrypt(cipher, clear)
 u_char *cipher;	/* IN  8 octets */
 u_char *clear;	/* OUT 8 octets */
 {
-	des_ecb_encrypt((des_cblock *)cipher, (des_cblock *)clear,
-	    key_schedule, 0);
+	DES_ecb_encrypt((DES_cblock *)cipher, (DES_cblock *)clear,
+	    &key_schedule, 0);
 	return (1);
 }