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kernel/Revert-the-random-series-for-4.16.4.patch

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From 4b97692c181f44717a5cf940fe1e6451c974f4b4 Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jeremy@jcline.org>
Date: Tue, 1 May 2018 18:52:14 -0400
Subject: [PATCH 1/4] Revert "random: add new ioctl RNDRESEEDCRNG"
This reverts commit e21e58679d3e9db0258106ffd3c8db76e66c5e6e.
Signed-off-by: Jeremy Cline <jeremy@jcline.org>
---
drivers/char/random.c | 13 +------------
include/uapi/linux/random.h | 3 ---
2 files changed, 1 insertion(+), 15 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 38729baed6ee..b3571a1c5fb7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -429,7 +429,6 @@ struct crng_state primary_crng = {
static int crng_init = 0;
#define crng_ready() (likely(crng_init > 1))
static int crng_init_cnt = 0;
-static unsigned long crng_global_init_time = 0;
#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)
static void _extract_crng(struct crng_state *crng,
__u32 out[CHACHA20_BLOCK_WORDS]);
@@ -906,8 +905,7 @@ static void _extract_crng(struct crng_state *crng,
unsigned long v, flags;
if (crng_ready() &&
- (time_after(crng_global_init_time, crng->init_time) ||
- time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL)))
+ time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL))
crng_reseed(crng, crng == &primary_crng ? &input_pool : NULL);
spin_lock_irqsave(&crng->lock, flags);
if (arch_get_random_long(&v))
@@ -1740,7 +1738,6 @@ static int rand_initialize(void)
init_std_data(&input_pool);
init_std_data(&blocking_pool);
crng_initialize(&primary_crng);
- crng_global_init_time = jiffies;
#ifdef CONFIG_NUMA
pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL);
@@ -1927,14 +1924,6 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
input_pool.entropy_count = 0;
blocking_pool.entropy_count = 0;
return 0;
- case RNDRESEEDCRNG:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- if (crng_init < 2)
- return -ENODATA;
- crng_reseed(&primary_crng, NULL);
- crng_global_init_time = jiffies - 1;
- return 0;
default:
return -EINVAL;
}
diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h
index 26ee91300e3e..c34f4490d025 100644
--- a/include/uapi/linux/random.h
+++ b/include/uapi/linux/random.h
@@ -35,9 +35,6 @@
/* Clear the entropy pool and associated counters. (Superuser only.) */
#define RNDCLEARPOOL _IO( 'R', 0x06 )
-/* Reseed CRNG. (Superuser only.) */
-#define RNDRESEEDCRNG _IO( 'R', 0x07 )
-
struct rand_pool_info {
int entropy_count;
int buf_size;
--
2.17.0
From 5084e3e3af02cdc4e247e66561215b6b06ccffc8 Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jeremy@jcline.org>
Date: Tue, 1 May 2018 18:52:17 -0400
Subject: [PATCH 2/4] Revert "random: crng_reseed() should lock the crng
instance that it is modifying"
This reverts commit 6efa23d5851f1702a3cddbdde63607ea6588b665.
Signed-off-by: Jeremy Cline <jeremy@jcline.org>
---
drivers/char/random.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index b3571a1c5fb7..fda8214543cc 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -879,7 +879,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
_crng_backtrack_protect(&primary_crng, buf.block,
CHACHA20_KEY_SIZE);
}
- spin_lock_irqsave(&crng->lock, flags);
+ spin_lock_irqsave(&primary_crng.lock, flags);
for (i = 0; i < 8; i++) {
unsigned long rv;
if (!arch_get_random_seed_long(&rv) &&
@@ -889,7 +889,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
}
memzero_explicit(&buf, sizeof(buf));
crng->init_time = jiffies;
- spin_unlock_irqrestore(&crng->lock, flags);
+ spin_unlock_irqrestore(&primary_crng.lock, flags);
if (crng == &primary_crng && crng_init < 2) {
invalidate_batched_entropy();
crng_init = 2;
--
2.17.0
From f3035506194216b5220be6fd8a2c5666412978a0 Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jeremy@jcline.org>
Date: Tue, 1 May 2018 18:52:19 -0400
Subject: [PATCH 3/4] Revert "random: use a different mixing algorithm for
add_device_randomness()"
This reverts commit 89b59f050347d376c2ace8b1ceb908a218cfdc2e.
Signed-off-by: Jeremy Cline <jeremy@jcline.org>
---
drivers/char/random.c | 55 ++++---------------------------------------
1 file changed, 4 insertions(+), 51 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index fda8214543cc..d0b2f89e9c6e 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -786,10 +786,6 @@ static void crng_initialize(struct crng_state *crng)
crng->init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
}
-/*
- * crng_fast_load() can be called by code in the interrupt service
- * path. So we can't afford to dilly-dally.
- */
static int crng_fast_load(const char *cp, size_t len)
{
unsigned long flags;
@@ -816,51 +812,6 @@ static int crng_fast_load(const char *cp, size_t len)
return 1;
}
-/*
- * crng_slow_load() is called by add_device_randomness, which has two
- * attributes. (1) We can't trust the buffer passed to it is
- * guaranteed to be unpredictable (so it might not have any entropy at
- * all), and (2) it doesn't have the performance constraints of
- * crng_fast_load().
- *
- * So we do something more comprehensive which is guaranteed to touch
- * all of the primary_crng's state, and which uses a LFSR with a
- * period of 255 as part of the mixing algorithm. Finally, we do
- * *not* advance crng_init_cnt since buffer we may get may be something
- * like a fixed DMI table (for example), which might very well be
- * unique to the machine, but is otherwise unvarying.
- */
-static int crng_slow_load(const char *cp, size_t len)
-{
- unsigned long flags;
- static unsigned char lfsr = 1;
- unsigned char tmp;
- unsigned i, max = CHACHA20_KEY_SIZE;
- const char * src_buf = cp;
- char * dest_buf = (char *) &primary_crng.state[4];
-
- if (!spin_trylock_irqsave(&primary_crng.lock, flags))
- return 0;
- if (crng_init != 0) {
- spin_unlock_irqrestore(&primary_crng.lock, flags);
- return 0;
- }
- if (len > max)
- max = len;
-
- for (i = 0; i < max ; i++) {
- tmp = lfsr;
- lfsr >>= 1;
- if (tmp & 1)
- lfsr ^= 0xE1;
- tmp = dest_buf[i % CHACHA20_KEY_SIZE];
- dest_buf[i % CHACHA20_KEY_SIZE] ^= src_buf[i % len] ^ lfsr;
- lfsr += (tmp << 3) | (tmp >> 5);
- }
- spin_unlock_irqrestore(&primary_crng.lock, flags);
- return 1;
-}
-
static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
{
unsigned long flags;
@@ -1030,8 +981,10 @@ void add_device_randomness(const void *buf, unsigned int size)
unsigned long time = random_get_entropy() ^ jiffies;
unsigned long flags;
- if (!crng_ready() && size)
- crng_slow_load(buf, size);
+ if (!crng_ready()) {
+ crng_fast_load(buf, size);
+ return;
+ }
trace_add_device_randomness(size, _RET_IP_);
spin_lock_irqsave(&input_pool.lock, flags);
--
2.17.0
From fc6be05c0f6503dab8e2c5c69cafda38d9d9417a Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jeremy@jcline.org>
Date: Tue, 1 May 2018 18:52:20 -0400
Subject: [PATCH 4/4] Revert "random: fix crng_ready() test"
This reverts commit cd8d7a5778a4abf76ee8fe8f1bfcf78976029f8d.
Signed-off-by: Jeremy Cline <jeremy@jcline.org>
---
drivers/char/random.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c
index d0b2f89e9c6e..11c23ca57430 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -427,7 +427,7 @@ struct crng_state primary_crng = {
* its value (from 0->1->2).
*/
static int crng_init = 0;
-#define crng_ready() (likely(crng_init > 1))
+#define crng_ready() (likely(crng_init > 0))
static int crng_init_cnt = 0;
#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)
static void _extract_crng(struct crng_state *crng,
@@ -793,7 +793,7 @@ static int crng_fast_load(const char *cp, size_t len)
if (!spin_trylock_irqsave(&primary_crng.lock, flags))
return 0;
- if (crng_init != 0) {
+ if (crng_ready()) {
spin_unlock_irqrestore(&primary_crng.lock, flags);
return 0;
}
@@ -855,7 +855,7 @@ static void _extract_crng(struct crng_state *crng,
{
unsigned long v, flags;
- if (crng_ready() &&
+ if (crng_init > 1 &&
time_after(jiffies, crng->init_time + CRNG_RESEED_INTERVAL))
crng_reseed(crng, crng == &primary_crng ? &input_pool : NULL);
spin_lock_irqsave(&crng->lock, flags);
@@ -1141,7 +1141,7 @@ void add_interrupt_randomness(int irq, int irq_flags)
fast_mix(fast_pool);
add_interrupt_bench(cycles);
- if (unlikely(crng_init == 0)) {
+ if (!crng_ready()) {
if ((fast_pool->count >= 64) &&
crng_fast_load((char *) fast_pool->pool,
sizeof(fast_pool->pool))) {
@@ -2214,7 +2214,7 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
{
struct entropy_store *poolp = &input_pool;
- if (unlikely(crng_init == 0)) {
+ if (!crng_ready()) {
crng_fast_load(buffer, count);
return;
}
--
2.17.0
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