From a6a26911cc7888458bd91feb433df584d7dcd5c8 Mon Sep 17 00:00:00 2001 From: Michael Jeanson Date: Tue, 21 May 2019 16:33:14 -0400 Subject: [PATCH] fix: random: only read from /dev/random after its pool has received 128 bits (v5.2) See upstream commit: commit eb9d1bf079bb438d1a066d72337092935fc770f6 Author: Theodore Ts'o Date: Wed Feb 20 16:06:38 2019 -0500 random: only read from /dev/random after its pool has received 128 bits Immediately after boot, we allow reads from /dev/random before its entropy pool has been fully initialized. Fix this so that we don't allow this until the blocking pool has received 128 bits. We do this by repurposing the initialized flag in the entropy pool struct, and use the initialized flag in the blocking pool to indicate whether it is safe to pull from the blocking pool. To do this, we needed to rework when we decide to push entropy from the input pool to the blocking pool, since the initialized flag for the input pool was used for this purpose. To simplify things, we no longer use the initialized flag for that purpose, nor do we use the entropy_total field any more. Signed-off-by: Michael Jeanson Signed-off-by: Mathieu Desnoyers --- instrumentation/events/lttng-module/random.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/instrumentation/events/lttng-module/random.h b/instrumentation/events/lttng-module/random.h index f1656000..80b22796 100644 --- a/instrumentation/events/lttng-module/random.h +++ b/instrumentation/events/lttng-module/random.h @@ -38,6 +38,24 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(random__mix_pool_bytes, mix_pool_bytes_noloc TP_ARGS(pool_name, bytes, IP) ) +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,2,0)) +LTTNG_TRACEPOINT_EVENT_MAP(credit_entropy_bits, + + random_credit_entropy_bits, + + TP_PROTO(const char *pool_name, int bits, int entropy_count, + unsigned long IP), + + TP_ARGS(pool_name, bits, entropy_count, IP), + + TP_FIELDS( + ctf_string(pool_name, pool_name) + ctf_integer(int, bits, bits) + ctf_integer(int, entropy_count, entropy_count) + ctf_integer(unsigned long, IP, IP) + ) +) +#else LTTNG_TRACEPOINT_EVENT_MAP(credit_entropy_bits, random_credit_entropy_bits, @@ -55,6 +73,7 @@ LTTNG_TRACEPOINT_EVENT_MAP(credit_entropy_bits, ctf_integer(unsigned long, IP, IP) ) ) +#endif LTTNG_TRACEPOINT_EVENT_MAP(get_random_bytes, -- 2.34.1