[libvirt] [PATCHv3] build: avoid -lgcrypt with newer gnutls
Eric Blake
eblake at redhat.com
Tue Aug 6 17:39:10 UTC 2013
ping
On 07/30/2013 02:45 PM, Eric Blake wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=951637
>
> Newer gnutls uses nettle, rather than gcrypt, which is a lot nicer
> regarding initialization. Yet we were unconditionally initializing
> gcrypt even when gnutls wouldn't be using it, and having two crypto
> libraries linked into libvirt.so is pointless, but mostly harmless
> (it doesn't crash, but does interfere with certification efforts).
>
> There are three distinct version ranges to worry about when
> determining which crypto lib gnutls uses, per these gnutls mails:
> 2.12: http://lists.gnu.org/archive/html/gnutls-devel/2011-03/msg00034.html
> 3.0: http://lists.gnu.org/archive/html/gnutls-devel/2011-07/msg00035.html
>
> If pkg-config can prove version numbers and/or list the crypto
> library used for static linking, we have our proof; if not, it
> is safer (even if pointless) to continue to use gcrypt ourselves.
>
> * configure.ac (WITH_GNUTLS): Probe whether to add -lgcrypt, and
> define a witness WITH_GNUTLS_GCRYPT.
> * src/libvirt.c (virTLSMutexInit, virTLSMutexDestroy)
> (virTLSMutexLock, virTLSMutexUnlock, virTLSThreadImpl)
> (virGlobalInit): Honor the witness.
> * libvirt.spec.in (BuildRequires): Make gcrypt usage conditional,
> no longer needed in Fedora 19.
>
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
>
> v3: configure logic is enhanced to try harder to get the
> right answer for gentoo. I tested with Fedora 19 and RHEL 6,
> but need feedback from a gentoo tester before this can go in.
>
> configure.ac | 37 ++++++++++++++++++++++++++++++-------
> libvirt.spec.in | 2 ++
> src/libvirt.c | 10 ++++++----
> 3 files changed, 38 insertions(+), 11 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 1817126..e3d148c 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1076,12 +1076,26 @@ if test "x$with_gnutls" != "xno"; then
> LIBS="$LIBS $GNUTLS_LIBS"
>
> GNUTLS_FOUND=no
> + GNUTLS_GCRYPT=unknown
> if test -x "$PKG_CONFIG" ; then
> + dnl Triple probe: gnutls < 2.12 only used gcrypt, gnutls >= 3.0 uses
> + dnl only nettle, and versions in between had a configure option.
> + dnl Our goal is to avoid gcrypt if we can prove gnutls uses nettle,
> + dnl but it is a safe fallback to use gcrypt if we can't prove anything.
> + if $PKG_CONFIG --exists 'gnutls >= 3.0'; then
> + GNUTLS_GCRYPT=no
> + elif $PKG_CONFIG --exists 'gnutls >= 2.12'; then
> + GNUTLS_GCRYPT=probe
> + else
> + GNUTLS_GCRYPT=yes
> + fi
> PKG_CHECK_MODULES(GNUTLS, gnutls >= $GNUTLS_REQUIRED,
> [GNUTLS_FOUND=yes], [GNUTLS_FOUND=no])
> fi
> if test "$GNUTLS_FOUND" = "no"; then
> + dnl pkg-config couldn't help us, assume gcrypt is necessary
> fail=0
> + GNUTLS_GCRYPT=yes
> AC_CHECK_HEADER([gnutls/gnutls.h], [], [fail=1])
> AC_CHECK_LIB([gnutls], [gnutls_handshake],[], [fail=1], [-lgcrypt])
>
> @@ -1098,13 +1112,22 @@ if test "x$with_gnutls" != "xno"; then
> AC_MSG_ERROR([You must install the GnuTLS library in order to compile and run libvirt])
> fi
> else
> - dnl Not all versions of gnutls include -lgcrypt, and so we add
> - dnl it explicitly for the calls to gcry_control/check_version
> - GNUTLS_LIBS="$GNUTLS_LIBS -lgcrypt"
> -
> - dnl We're not using gcrypt deprecated features so define
> - dnl GCRYPT_NO_DEPRECATED to avoid deprecated warnings
> - GNUTLS_CFLAGS="$GNUTLS_CFLAGS -DGCRYPT_NO_DEPRECATED"
> + dnl See comments above about when to use gcrypt.
> + if test "$GNUTLS_GCRYPT" = probe; then
> + case `$PKG_CONFIG --libs --static gnutls` in
> + *gcrypt*) GNUTLS_GCRYPT=yes ;;
> + *nettle*) GNUTLS_GCRYPT=no ;;
> + *) GNUTLS_GCRYPT=unknown ;;
> + esac
> + fi
> + if test "$GNUTLS_GCRYPT" = yes || test "$GNUTLS_GCRYPT" = unknown; then
> + GNUTLS_LIBS="$GNUTLS_LIBS -lgcrypt"
> + dnl We're not using gcrypt deprecated features so define
> + dnl GCRYPT_NO_DEPRECATED to avoid deprecated warnings
> + GNUTLS_CFLAGS="$GNUTLS_CFLAGS -DGCRYPT_NO_DEPRECATED"
> + AC_DEFINE_UNQUOTED([WITH_GNUTLS_GCRYPT], 1,
> + [set to 1 if it is known or assumed that GNUTLS uses gcrypt])
> + fi
>
> dnl gnutls 3.x moved some declarations to a new header
> AC_CHECK_HEADERS([gnutls/crypto.h], [], [], [[
> diff --git a/libvirt.spec.in b/libvirt.spec.in
> index fce7f91..7fd3c85 100644
> --- a/libvirt.spec.in
> +++ b/libvirt.spec.in
> @@ -438,7 +438,9 @@ BuildRequires: readline-devel
> BuildRequires: ncurses-devel
> BuildRequires: gettext
> BuildRequires: libtasn1-devel
> +%if (0%{?rhel} && 0%{?rhel} < 7) || (0%{?fedora} && 0%{?fedora} < 19)
> BuildRequires: libgcrypt-devel
> +%endif
> BuildRequires: gnutls-devel
> BuildRequires: libattr-devel
> %if %{with_libvirtd}
> diff --git a/src/libvirt.c b/src/libvirt.c
> index 8157488..66e8248 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -55,7 +55,9 @@
> #include "intprops.h"
> #include "virconf.h"
> #if WITH_GNUTLS
> -# include <gcrypt.h>
> +# if WITH_GNUTLS_GCRYPT
> +# include <gcrypt.h>
> +# endif
> # include "rpc/virnettlscontext.h"
> #endif
> #include "vircommand.h"
> @@ -270,7 +272,7 @@ winsock_init(void)
> #endif
>
>
> -#ifdef WITH_GNUTLS
> +#ifdef WITH_GNUTLS_GCRYPT
> static int virTLSMutexInit(void **priv)
> {
> virMutexPtr lock = NULL;
> @@ -323,7 +325,7 @@ static struct gcry_thread_cbs virTLSThreadImpl = {
> virTLSMutexUnlock,
> NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
> };
> -#endif
> +#endif /* WITH_GNUTLS_GCRYPT */
>
> /* Helper macros to implement VIR_DOMAIN_DEBUG using just C99. This
> * assumes you pass fewer than 15 arguments to VIR_DOMAIN_DEBUG, but
> @@ -407,7 +409,7 @@ virGlobalInit(void)
> virErrorInitialize() < 0)
> goto error;
>
> -#ifdef WITH_GNUTLS
> +#ifdef WITH_GNUTLS_GCRYPT
> /*
> * This sequence of API calls it copied exactly from
> * gnutls 2.12.23 source lib/gcrypt/init.c, with
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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