As discussed in [1], there is a problem with get_random_bytes being used before the RNG has actually been seeded. The solution for fixing this appears to be multi-pronged. One of those prongs involves adding a simple blocking API so that modules that use the RNG in process context can just sleep (in an interruptable manner) until the RNG is ready to be used. This winds up being a very useful API that covers a few use cases, 5 of which are included in this patch set. [1] http://www.openwall.com/lists/kernel-hardening/2017/06/02/2 Changes v1->v2: - Rather than support both interruptable and non-interruptable waiting and also timeouts, we just support the case that people will actually use: ordinary interruptable waiting. This simplifies the API a bit. - This patch set now has a few examples of where it might be useful. Jason A. Donenfeld (8): random: add synchronous API for the urandom pool random: add get_random_{bytes,u32,u64,int,long,once}_wait family random: warn when kernel uses unseeded randomness crypto/rng: ensure that the RNG is ready before using security/keys: ensure RNG is seeded before use iscsi: ensure RNG is seeded before use bluetooth/smp: ensure RNG is properly seeded before ECDH use ceph: ensure RNG is seeded before using crypto/rng.c | 6 +++-- drivers/char/random.c | 44 ++++++++++++++++++++++--------- drivers/target/iscsi/iscsi_target_auth.c | 14 +++++++--- drivers/target/iscsi/iscsi_target_login.c | 22 ++++++++++------ include/linux/net.h | 2 ++ include/linux/once.h | 2 ++ include/linux/random.h | 26 ++++++++++++++++++ lib/Kconfig.debug | 15 +++++++++++ net/bluetooth/hci_request.c | 6 +++++ net/bluetooth/smp.c | 18 ++++++++++--- net/ceph/ceph_common.c | 6 ++++- security/keys/encrypted-keys/encrypted.c | 8 +++--- security/keys/key.c | 13 ++++++--- 13 files changed, 145 insertions(+), 37 deletions(-) -- 2.13.0
