diff options
| author | Max <msuraev@sysmocom.de> | 2017-10-26 10:56:04 +0200 |
|---|---|---|
| committer | Harald Welte <laforge@gnumonks.org> | 2017-11-02 18:06:26 +0000 |
| commit | ed029dfab959bca74bd43d86922727c2047eeb4d (patch) | |
| tree | 07ed1e7bff8b0f154e949b62ffc1b0ba60098e4f /src/gsm/gsm_utils.c | |
| parent | 69b61fe510dd9357040ad0a9f3a1449d913067a7 (diff) | |
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
Diffstat (limited to 'src/gsm/gsm_utils.c')
| -rw-r--r-- | src/gsm/gsm_utils.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/src/gsm/gsm_utils.c b/src/gsm/gsm_utils.c index e3f792ef..134b4752 100644 --- a/src/gsm/gsm_utils.c +++ b/src/gsm/gsm_utils.c @@ -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 |