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 v2->v3: - Since this issue, in general, is going to take a long time to fully fix, the patch turning on the warning is now dependent on DEBUG_KERNEL so that the right people see the messages but the others aren't annoyed. - Fixed some inappropriate blocking for functions that load during module insertion. As discussed in [1], module insertion deferal is a topic for another patch set. - An interesting and essential patch has been added for invalidating the batched entropy pool after the crng initializes. - Some places that need randomness at bootup for just small integers would be better served by get_random_{u32,u64}, so this series makes those changes in a few places. It's useful here, since on some architectures that delivers better early randomness. Jason A. Donenfeld (13): random: add synchronous API for the urandom pool random: add get_random_{bytes,u32,u64,int,long,once}_wait family random: invalidate batched entropy after crng init 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 ceph: ensure RNG is seeded before using cifs: use get_random_u32 for 32-bit lock random rhashtable: use get_random_u32 for hash_rnd net/neighbor: use get_random_u32 for 32-bit hash random net/route: use get_random_int for random counter bluetooth/smp: ensure RNG is properly seeded before ECDH use random: warn when kernel uses unseeded randomness crypto/rng.c | 6 ++- drivers/char/random.c | 90 ++++++++++++++++++++++++++----- drivers/target/iscsi/iscsi_target_auth.c | 14 +++-- drivers/target/iscsi/iscsi_target_login.c | 22 +++++--- fs/cifs/cifsfs.c | 2 +- include/linux/net.h | 2 + include/linux/once.h | 2 + include/linux/random.h | 26 +++++++++ lib/Kconfig.debug | 16 ++++++ lib/rhashtable.c | 2 +- net/bluetooth/hci_request.c | 6 +++ net/bluetooth/smp.c | 18 +++++-- net/ceph/ceph_common.c | 6 ++- net/core/neighbour.c | 3 +- net/ipv4/route.c | 3 +- security/keys/encrypted-keys/encrypted.c | 8 +-- security/keys/key.c | 16 +++--- 17 files changed, 195 insertions(+), 47 deletions(-) -- 2.13.0
