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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 16:22:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-12 16:22:22 -0800
commit268325bda5299836a6ad4c3952474a2be125da5f (patch)
tree5f7b22109b7a21d0aab68cab8de0ee201426aae1 /lib
parentca1443c7e75a28c6fde5c67cb1904b624cf43c36 (diff)
parent3e6743e28b9b43d37ced234bdf8e19955d0216f8 (diff)
Merge tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld: - Replace prandom_u32_max() and various open-coded variants of it, there is now a new family of functions that uses fast rejection sampling to choose properly uniformly random numbers within an interval: get_random_u32_below(ceil) - [0, ceil) get_random_u32_above(floor) - (floor, U32_MAX] get_random_u32_inclusive(floor, ceil) - [floor, ceil] Coccinelle was used to convert all current users of prandom_u32_max(), as well as many open-coded patterns, resulting in improvements throughout the tree. I'll have a "late" 6.1-rc1 pull for you that removes the now unused prandom_u32_max() function, just in case any other trees add a new use case of it that needs to converted. According to linux-next, there may be two trivial cases of prandom_u32_max() reintroductions that are fixable with a 's/.../.../'. So I'll have for you a final conversion patch doing that alongside the removal patch during the second week. This is a treewide change that touches many files throughout. - More consistent use of get_random_canary(). - Updates to comments, documentation, tests, headers, and simplification in configuration. - The arch_get_random*_early() abstraction was only used by arm64 and wasn't entirely useful, so this has been replaced by code that works in all relevant contexts. - The kernel will use and manage random seeds in non-volatile EFI variables, refreshing a variable with a fresh seed when the RNG is initialized. The RNG GUID namespace is then hidden from efivarfs to prevent accidental leakage. These changes are split into random.c infrastructure code used in the EFI subsystem, in this pull request, and related support inside of EFISTUB, in Ard's EFI tree. These are co-dependent for full functionality, but the order of merging doesn't matter. - Part of the infrastructure added for the EFI support is also used for an improvement to the way vsprintf initializes its siphash key, replacing an sleep loop wart. - The hardware RNG framework now always calls its correct random.c input function, add_hwgenerator_randomness(), rather than sometimes going through helpers better suited for other cases. - The add_latent_entropy() function has long been called from the fork handler, but is a no-op when the latent entropy gcc plugin isn't used, which is fine for the purposes of latent entropy. But it was missing out on the cycle counter that was also being mixed in beside the latent entropy variable. So now, if the latent entropy gcc plugin isn't enabled, add_latent_entropy() will expand to a call to add_device_randomness(NULL, 0), which adds a cycle counter, without the absent latent entropy variable. - The RNG is now reseeded from a delayed worker, rather than on demand when used. Always running from a worker allows it to make use of the CPU RNG on platforms like S390x, whose instructions are too slow to do so from interrupts. It also has the effect of adding in new inputs more frequently with more regularity, amounting to a long term transcript of random values. Plus, it helps a bit with the upcoming vDSO implementation (which isn't yet ready for 6.2). - The jitter entropy algorithm now tries to execute on many different CPUs, round-robining, in hopes of hitting even more memory latencies and other unpredictable effects. It also will mix in a cycle counter when the entropy timer fires, in addition to being mixed in from the main loop, to account more explicitly for fluctuations in that timer firing. And the state it touches is now kept within the same cache line, so that it's assured that the different execution contexts will cause latencies. * tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (23 commits) random: include <linux/once.h> in the right header random: align entropy_timer_state to cache line random: mix in cycle counter when jitter timer fires random: spread out jitter callback to different CPUs random: remove extraneous period and add a missing one in comments efi: random: refresh non-volatile random seed when RNG is initialized vsprintf: initialize siphash key using notifier random: add back async readiness notifier random: reseed in delayed work rather than on-demand random: always mix cycle counter in add_latent_entropy() hw_random: use add_hwgenerator_randomness() for early entropy random: modernize documentation comment on get_random_bytes() random: adjust comment to account for removed function random: remove early archrandom abstraction random: use random.trust_{bootloader,cpu} command line option only stackprotector: actually use get_random_canary() stackprotector: move get_random_canary() into stackprotector.h treewide: use get_random_u32_inclusive() when possible treewide: use get_random_u32_{above,below}() instead of manual loop treewide: use get_random_u32_below() instead of deprecated function ...
Diffstat (limited to 'lib')
-rw-r--r--lib/fault-inject.c2
-rw-r--r--lib/find_bit_benchmark.c4
-rw-r--r--lib/kobject.c2
-rw-r--r--lib/reed_solomon/test_rslib.c6
-rw-r--r--lib/sbitmap.c4
-rw-r--r--lib/test-string_helpers.c2
-rw-r--r--lib/test_fprobe.c5
-rw-r--r--lib/test_hexdump.c10
-rw-r--r--lib/test_kprobes.c5
-rw-r--r--lib/test_list_sort.c2
-rw-r--r--lib/test_printf.c2
-rw-r--r--lib/test_rhashtable.c6
-rw-r--r--lib/test_vmalloc.c8
-rw-r--r--lib/vsprintf.c14
14 files changed, 31 insertions, 41 deletions
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index adb2f9355ee6..1421818c9ef7 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -136,7 +136,7 @@ bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags)
return false;
}
- if (attr->probability <= prandom_u32_max(100))
+ if (attr->probability <= get_random_u32_below(100))
return false;
if (!fail_stacktrace(attr))
diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
index 7c3c011abd29..d3fb09e6eff1 100644
--- a/lib/find_bit_benchmark.c
+++ b/lib/find_bit_benchmark.c
@@ -174,8 +174,8 @@ static int __init find_bit_test(void)
bitmap_zero(bitmap2, BITMAP_LEN);
while (nbits--) {
- __set_bit(prandom_u32_max(BITMAP_LEN), bitmap);
- __set_bit(prandom_u32_max(BITMAP_LEN), bitmap2);
+ __set_bit(get_random_u32_below(BITMAP_LEN), bitmap);
+ __set_bit(get_random_u32_below(BITMAP_LEN), bitmap2);
}
test_find_next_bit(bitmap, BITMAP_LEN);
diff --git a/lib/kobject.c b/lib/kobject.c
index a0b2dbfcfa23..af1f5f2954d4 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -694,7 +694,7 @@ static void kobject_release(struct kref *kref)
{
struct kobject *kobj = container_of(kref, struct kobject, kref);
#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
- unsigned long delay = HZ + HZ * prandom_u32_max(4);
+ unsigned long delay = HZ + HZ * get_random_u32_below(4);
pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
kobject_name(kobj), kobj, __func__, kobj->parent, delay);
INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
diff --git a/lib/reed_solomon/test_rslib.c b/lib/reed_solomon/test_rslib.c
index 848e7eb5da92..75cb1adac884 100644
--- a/lib/reed_solomon/test_rslib.c
+++ b/lib/reed_solomon/test_rslib.c
@@ -183,7 +183,7 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
do {
/* Must not choose the same location twice */
- errloc = prandom_u32_max(len);
+ errloc = get_random_u32_below(len);
} while (errlocs[errloc] != 0);
errlocs[errloc] = 1;
@@ -194,12 +194,12 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
for (i = 0; i < eras; i++) {
do {
/* Must not choose the same location twice */
- errloc = prandom_u32_max(len);
+ errloc = get_random_u32_below(len);
} while (errlocs[errloc] != 0);
derrlocs[i] = errloc;
- if (ewsc && prandom_u32_max(2)) {
+ if (ewsc && get_random_u32_below(2)) {
/* Erasure with the symbol intact */
errlocs[errloc] = 2;
} else {
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 7280ae8ca88c..58de526ff051 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -21,7 +21,7 @@ static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
int i;
for_each_possible_cpu(i)
- *per_cpu_ptr(sb->alloc_hint, i) = prandom_u32_max(depth);
+ *per_cpu_ptr(sb->alloc_hint, i) = get_random_u32_below(depth);
}
return 0;
}
@@ -33,7 +33,7 @@ static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
hint = this_cpu_read(*sb->alloc_hint);
if (unlikely(hint >= depth)) {
- hint = depth ? prandom_u32_max(depth) : 0;
+ hint = depth ? get_random_u32_below(depth) : 0;
this_cpu_write(*sb->alloc_hint, hint);
}
diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index 86fadd3ba08c..41d3447bc3b4 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -587,7 +587,7 @@ static int __init test_string_helpers_init(void)
for (i = 0; i < UNESCAPE_ALL_MASK + 1; i++)
test_string_unescape("unescape", i, false);
test_string_unescape("unescape inplace",
- prandom_u32_max(UNESCAPE_ANY + 1), true);
+ get_random_u32_below(UNESCAPE_ANY + 1), true);
/* Without dictionary */
for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
diff --git a/lib/test_fprobe.c b/lib/test_fprobe.c
index e0381b3ec410..1fb56cf5e5ce 100644
--- a/lib/test_fprobe.c
+++ b/lib/test_fprobe.c
@@ -144,10 +144,7 @@ static unsigned long get_ftrace_location(void *func)
static int fprobe_test_init(struct kunit *test)
{
- do {
- rand1 = get_random_u32();
- } while (rand1 <= div_factor);
-
+ rand1 = get_random_u32_above(div_factor);
target = fprobe_selftest_target;
target2 = fprobe_selftest_target2;
target_ip = get_ftrace_location(target);
diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
index 0927f44cd478..b916801f23a8 100644
--- a/lib/test_hexdump.c
+++ b/lib/test_hexdump.c
@@ -149,7 +149,7 @@ static void __init test_hexdump(size_t len, int rowsize, int groupsize,
static void __init test_hexdump_set(int rowsize, bool ascii)
{
size_t d = min_t(size_t, sizeof(data_b), rowsize);
- size_t len = prandom_u32_max(d) + 1;
+ size_t len = get_random_u32_inclusive(1, d);
test_hexdump(len, rowsize, 4, ascii);
test_hexdump(len, rowsize, 2, ascii);
@@ -208,11 +208,11 @@ static void __init test_hexdump_overflow(size_t buflen, size_t len,
static void __init test_hexdump_overflow_set(size_t buflen, bool ascii)
{
unsigned int i = 0;
- int rs = (prandom_u32_max(2) + 1) * 16;
+ int rs = get_random_u32_inclusive(1, 2) * 16;
do {
int gs = 1 << i;
- size_t len = prandom_u32_max(rs) + gs;
+ size_t len = get_random_u32_below(rs) + gs;
test_hexdump_overflow(buflen, rounddown(len, gs), rs, gs, ascii);
} while (i++ < 3);
@@ -223,11 +223,11 @@ static int __init test_hexdump_init(void)
unsigned int i;
int rowsize;
- rowsize = (prandom_u32_max(2) + 1) * 16;
+ rowsize = get_random_u32_inclusive(1, 2) * 16;
for (i = 0; i < 16; i++)
test_hexdump_set(rowsize, false);
- rowsize = (prandom_u32_max(2) + 1) * 16;
+ rowsize = get_random_u32_inclusive(1, 2) * 16;
for (i = 0; i < 16; i++)
test_hexdump_set(rowsize, true);
diff --git a/lib/test_kprobes.c b/lib/test_kprobes.c
index eeb1d728d974..1c95e5719802 100644
--- a/lib/test_kprobes.c
+++ b/lib/test_kprobes.c
@@ -339,10 +339,7 @@ static int kprobes_test_init(struct kunit *test)
stacktrace_target = kprobe_stacktrace_target;
internal_target = kprobe_stacktrace_internal_target;
stacktrace_driver = kprobe_stacktrace_driver;
-
- do {
- rand1 = get_random_u32();
- } while (rand1 <= div_factor);
+ rand1 = get_random_u32_above(div_factor);
return 0;
}
diff --git a/lib/test_list_sort.c b/lib/test_list_sort.c
index 19ff229b9c3a..cc5f335f29b5 100644
--- a/lib/test_list_sort.c
+++ b/lib/test_list_sort.c
@@ -71,7 +71,7 @@ static void list_sort_test(struct kunit *test)
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, el);
/* force some equivalencies */
- el->value = prandom_u32_max(TEST_LIST_LEN / 3);
+ el->value = get_random_u32_below(TEST_LIST_LEN / 3);
el->serial = i;
el->poison1 = TEST_POISON1;
el->poison2 = TEST_POISON2;
diff --git a/lib/test_printf.c b/lib/test_printf.c
index d6a5d4b5f884..d34dc636b81c 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -126,7 +126,7 @@ __test(const char *expect, int elen, const char *fmt, ...)
* be able to print it as expected.
*/
failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap);
- rand = 1 + prandom_u32_max(elen+1);
+ rand = get_random_u32_inclusive(1, elen + 1);
/* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */
failed_tests += do_test(rand, expect, elen, fmt, ap);
failed_tests += do_test(0, expect, elen, fmt, ap);
diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index f2ba5787055a..6a8e445c8b55 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -368,8 +368,8 @@ static int __init test_rhltable(unsigned int entries)
pr_info("test %d random rhlist add/delete operations\n", entries);
for (j = 0; j < entries; j++) {
- u32 i = prandom_u32_max(entries);
- u32 prand = prandom_u32_max(4);
+ u32 i = get_random_u32_below(entries);
+ u32 prand = get_random_u32_below(4);
cond_resched();
@@ -396,7 +396,7 @@ static int __init test_rhltable(unsigned int entries)
}
if (prand & 2) {
- i = prandom_u32_max(entries);
+ i = get_random_u32_below(entries);
if (test_bit(i, obj_in_table)) {
err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
WARN(err, "cannot remove element at slot %d", i);
diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c
index cf7780572f5b..f90d2c27675b 100644
--- a/lib/test_vmalloc.c
+++ b/lib/test_vmalloc.c
@@ -151,7 +151,7 @@ static int random_size_alloc_test(void)
int i;
for (i = 0; i < test_loop_count; i++) {
- n = prandom_u32_max(100) + 1;
+ n = get_random_u32_inclusive(1, 100);
p = vmalloc(n * PAGE_SIZE);
if (!p)
@@ -291,12 +291,12 @@ pcpu_alloc_test(void)
return -1;
for (i = 0; i < 35000; i++) {
- size = prandom_u32_max(PAGE_SIZE / 4) + 1;
+ size = get_random_u32_inclusive(1, PAGE_SIZE / 4);
/*
* Maximum PAGE_SIZE
*/
- align = 1 << (prandom_u32_max(11) + 1);
+ align = 1 << get_random_u32_inclusive(1, 11);
pcpu[i] = __alloc_percpu(size, align);
if (!pcpu[i])
@@ -391,7 +391,7 @@ static void shuffle_array(int *arr, int n)
for (i = n - 1; i > 0; i--) {
/* Cut the range. */
- j = prandom_u32_max(i);
+ j = get_random_u32_below(i);
/* Swap indexes. */
swap(arr[i], arr[j]);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 5b0611c00956..be71a03c936a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -41,6 +41,7 @@
#include <linux/siphash.h>
#include <linux/compiler.h>
#include <linux/property.h>
+#include <linux/notifier.h>
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
#endif
@@ -752,26 +753,21 @@ early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
static bool filled_random_ptr_key __read_mostly;
static siphash_key_t ptr_key __read_mostly;
-static void fill_ptr_key_workfn(struct work_struct *work);
-static DECLARE_DELAYED_WORK(fill_ptr_key_work, fill_ptr_key_workfn);
-static void fill_ptr_key_workfn(struct work_struct *work)
+static int fill_ptr_key(struct notifier_block *nb, unsigned long action, void *data)
{
- if (!rng_is_initialized()) {
- queue_delayed_work(system_unbound_wq, &fill_ptr_key_work, HZ * 2);
- return;
- }
-
get_random_bytes(&ptr_key, sizeof(ptr_key));
/* Pairs with smp_rmb() before reading ptr_key. */
smp_wmb();
WRITE_ONCE(filled_random_ptr_key, true);
+ return NOTIFY_DONE;
}
static int __init vsprintf_init_hashval(void)
{
- fill_ptr_key_workfn(NULL);
+ static struct notifier_block fill_ptr_key_nb = { .notifier_call = fill_ptr_key };
+ execute_with_initialized_rng(&fill_ptr_key_nb);
return 0;
}
subsys_initcall(vsprintf_init_hashval)