From 35fec3ea0ef5c3c068f698e1b2a94695522f8e47 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 9 Apr 2024 15:43:02 +0200
Subject: [PATCH] login: add support for gnutls

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure.ac    | 26 ++++++++++++++++++++++++--
 lib/Makefile.am |  2 +-
 lib/login.c     | 19 ++++++++++++++++++-
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index b7d214f..13ae3bb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -78,11 +78,29 @@ AM_CONDITIONAL([BUILD_EXAMPLES],
 
 AC_CONFIG_HEADERS([config.h])
 
+AC_ARG_WITH([gnutls],
+	    [AS_HELP_STRING([--with-gnutls],
+			    [Use gnutls to compute MD5])],
+	    [WITH_GNUTLS=$withval],
+	    [WITH_GNUTLS=auto])
+
 AC_ARG_WITH([libgcrypt],
 	    [AS_HELP_STRING([--with-libgcrypt],
 			    [Use libgcrypt to compute MD5])],
 	    [WITH_LIBGCRYPT=$withval],
 	    [WITH_LIBGCRYPT=auto])
+
+if test "$WITH_GNUTLS" != no; then
+  AC_CHECK_LIB([gnutls], [gnutls_hash_init])
+  if test "$WITH_GNUTLS" = yes && test "$ac_cv_lib_gnutls_gnutls_hash_init" != yes; then
+    AC_MSG_ERROR([gnutls not found])
+  fi
+  WITH_GNUTLS=$ac_cv_lib_gnutls_gnutls_hash_init
+fi
+if test "$WITH_GNUTLS" = yes; then
+  WITH_LIBGCRYPT=no
+fi
+
 if test "$WITH_LIBGCRYPT" != no; then
   AC_CHECK_LIB([gcrypt], [gcry_control])
   if test "$WITH_LIBGCRYPT" = yes && test "$ac_cv_lib_gcrypt_gcry_control" != yes; then
@@ -91,8 +109,12 @@ if test "$WITH_LIBGCRYPT" != no; then
   WITH_LIBGCRYPT=$ac_cv_lib_gcrypt_gcry_control
 fi
 
-AM_CONDITIONAL([HAVE_LIBGCRYPT],
-	       [expr "$WITH_LIBGCRYPT" : yes > /dev/null 2>&1])
+NEED_MD5=no
+if test "$WITH_GNUTLS" = no && test "$WITH_LIBGCRYPT" = no; then
+  NEED_MD5=yes
+fi
+AM_CONDITIONAL([NEED_MD5],
+	       [expr "$NEED_MD5" : yes > /dev/null 2>&1])
 
 # For MinGW.
 AC_CHECK_LIB([ws2_32], [gethostbyname])
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 4cc03a9..ba6aaee 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -12,7 +12,7 @@ if TARGET_OS_IS_WIN32
 libiscsipriv_la_SOURCES += ../win32/win32_compat.c
 endif
 
-if !HAVE_LIBGCRYPT
+if NEED_MD5
 libiscsipriv_la_SOURCES += md5.c
 endif
 
diff --git a/lib/login.c b/lib/login.c
index 03c4a7d..5177201 100644
--- a/lib/login.c
+++ b/lib/login.c
@@ -44,6 +44,10 @@
 #include "iscsi-private.h"
 #include "scsi-lowlevel.h"
 #include "md5.h"
+
+#ifdef HAVE_LIBGNUTLS
+#include <gnutls/crypto.h>
+#endif
 #ifdef HAVE_LIBGCRYPT
 #include <gcrypt.h>
 #endif
@@ -681,7 +685,20 @@ i2h(int i)
 	return i + '0';
 }
 
-#ifdef HAVE_LIBGCRYPT
+#if defined HAVE_LIBGNUTLS
+#define md5_context_t gnutls_hash_hd_t
+#define md5_open(hd)  gnutls_hash_init(hd, GNUTLS_DIG_MD5)
+#define md5_write     gnutls_hash
+#define md5_read      gnutls_hash_output
+
+static void md5_close(md5_context_t h)
+{
+       unsigned char digest[16];
+
+       gnutls_hash_deinit(h, digest);
+}
+
+#elif defined HAVE_LIBGCRYPT
 typedef gcry_md_hd_t md5_context_t;
 #define md5_open(hd) gcry_md_open(hd, GCRY_MD_MD5, 0)
 #define md5_write gcry_md_write