osmocom
/
libosmocore
mirror of https://gerrit.osmocom.org/libosmocore
11
0
Fork 0
Code Issues Releases Wiki Activity

Enable GnuTLS fallback 

On systems with GNU/Linux kernel older than 3.17 (Debian 8 "jessie" for
example) the osmo_get_rand_id() would always return failure due to
missing getrandom() syscall.

To support such systems, let's add fallback code which uses GnuTLS
library. It can be disabled explicitly via '--disable-gnutls' option at
compile-time, otherwise ./configure will fail if both getrandom() and
GnuTLS are not available. When building with '--enable-embedded' the
fallback is disabled automatically.

Related: OS#1694

Change-Id: Ic77866ce65acf524b768882c751a4f9c0635740b
This commit is contained in:
Max 2017-10-26 10:56:04 +02:00 committed by Harald Welte
parent 69b61fe510
commit ed029dfab9
3 changed files with 36 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
configure.ac
View File

@ -130,6 +130,20 @@ AS_IF([test "x$ENABLE_PCSC" = "xyes"], [
AM_CONDITIONAL(ENABLE_PCSC, test "x$ENABLE_PCSC" = "xyes")
AC_SUBST(ENABLE_PCSC)
AC_ARG_ENABLE([gnutls], [AS_HELP_STRING([--disable-gnutls], [Do not use GnuTLS fallback for missing getrandom()])],
[ENABLE_GNUTLS=$enableval], [ENABLE_GNUTLS="yes"])
AM_CONDITIONAL(ENABLE_GNUTLS, test x"$ENABLE_GNUTLS" = x"yes")
AS_IF([test "x$ENABLE_GNUTLS" = "xyes"], [
PKG_CHECK_MODULES([LIBGNUTLS], [gnutls >= 2.12.0])
])
AC_SUBST(ENABLE_GNUTLS)
if test x"$ENABLE_GNUTLS" = x"yes"
then
AC_SUBST([LIBGNUTLS_CFLAGS])
AC_SUBST([LIBGNUTLS_LIBS])
AC_DEFINE([USE_GNUTLS], [1], [Use GnuTLS as a fallback for missing getrandom()])
fi
AC_ARG_ENABLE(plugin,
[AS_HELP_STRING(
[--disable-plugin],
@ -228,12 +242,15 @@ then
AM_CONDITIONAL(ENABLE_PLUGIN, false)
AM_CONDITIONAL(ENABLE_MSGFILE, false)
AM_CONDITIONAL(ENABLE_SERIAL, false)
AM_CONDITIONAL(ENABLE_GNUTLS, false)
AM_CONDITIONAL(ENABLE_VTY, false)
AM_CONDITIONAL(ENABLE_CTRL, false)
AM_CONDITIONAL(ENABLE_UTILITIES, false)
AM_CONDITIONAL(ENABLE_GB, false)
AM_CONDITIONAL(ENABLE_GNUTLS, false)
AM_CONDITIONAL(ENABLE_PCSC, false)
AM_CONDITIONAL(ENABLE_PSEUDOTALLOC, true)
AC_DEFINE([USE_GNUTLS], [0])
AC_DEFINE([PANIC_INFLOOP],[1],[Use infinite loop on panic rather than fprintf/abort])
fi

5
src/gsm/Makefile.am
View File

@ -38,6 +38,11 @@ libosmogsm_la_SOURCES =
libosmogsm_la_LDFLAGS = $(LTLDFLAGS_OSMOGSM) -version-info $(LIBVERSION) -no-undefined
libosmogsm_la_LIBADD = libgsmint.la $(TALLOC_LIBS)
if ENABLE_GNUTLS
AM_CPPFLAGS += $(LIBGNUTLS_CFLAGS)
libosmogsm_la_LIBADD += $(LIBGNUTLS_LIBS)
endif
EXTRA_DIST = libosmogsm.map
# Convolutional codes generation

19
src/gsm/gsm_utils.c
View File

@ -106,6 +106,12 @@
#endif
#endif
#if (USE_GNUTLS)
#pragma message ("including GnuTLS for getrandom fallback.")
#include <gnutls/gnutls.h>
#include <gnutls/crypto.h>
#endif
/* ETSI GSM 03.38 6.2.1 and 6.2.1.1 default alphabet
* Greek symbols at hex positions 0x10 and 0x12-0x1a
* left out as they can't be handled with a char and
@ -409,7 +415,7 @@ int gsm_7bit_encode_n_ussd(uint8_t *result, size_t n, const char *data, int *oct
*/
int osmo_get_rand_id(uint8_t *out, size_t len)
{
int rc;
int rc = -ENOTSUP;
/* this function is intended for generating short identifiers only, not arbitrary-length random data */
if (len > OSMO_MAX_RAND_ID_LEN)
@ -421,13 +427,16 @@ int osmo_get_rand_id(uint8_t *out, size_t len)
#pragma message ("Using direct syscall access for getrandom(): consider upgrading to glibc >= 2.25")
/* FIXME: this can be removed once we bump glibc requirements to 2.25: */
rc = syscall(SYS_getrandom, out, len, GRND_NONBLOCK);
#else
#pragma message ("Secure random unavailable: calls to osmo_get_rand_id() will always fail!")
return -ENOTSUP;
#endif
/* getrandom() failed entirely: */
if (rc < 0)
if (rc < 0) {
#if (USE_GNUTLS)
#pragma message ("Secure random failed: using GnuTLS fallback.")
return gnutls_rnd(GNUTLS_RND_RANDOM, out, len);
#endif
return -errno;
}
/* getrandom() failed partially due to signal interruption:
this should never happen (according to getrandom(2)) as long as OSMO_MAX_RAND_ID_LEN < 256