diff options
35 files changed, 784 insertions, 1355 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 1144ea3229a3..e9c18dabc552 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -994,6 +994,9 @@ This is a directory, with the following entries: * ``boot_id``: a UUID generated the first time this is retrieved, and unvarying after that; +* ``uuid``: a UUID generated every time this is retrieved (this can + thus be used to generate UUIDs at will); + * ``entropy_avail``: the pool's entropy count, in bits; * ``poolsize``: the entropy pool size, in bits; @@ -1001,10 +1004,7 @@ This is a directory, with the following entries: * ``urandom_min_reseed_secs``: obsolete (used to determine the minimum number of seconds between urandom pool reseeding). This file is writable for compatibility purposes, but writing to it has no effect - on any RNG behavior. - -* ``uuid``: a UUID generated every time this is retrieved (this can - thus be used to generate UUIDs at will); + on any RNG behavior; * ``write_wakeup_threshold``: when the entropy count drops below this (as a number of bits), processes waiting to write to ``/dev/random`` diff --git a/arch/alpha/include/asm/timex.h b/arch/alpha/include/asm/timex.h index b565cc6f408e..f89798da8a14 100644 --- a/arch/alpha/include/asm/timex.h +++ b/arch/alpha/include/asm/timex.h @@ -28,5 +28,6 @@ static inline cycles_t get_cycles (void) __asm__ __volatile__ ("rpcc %0" : "=r"(ret)); return ret; } +#define get_cycles get_cycles #endif diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h index 7c3b3671d6c2..6d1337c169cd 100644 --- a/arch/arm/include/asm/timex.h +++ b/arch/arm/include/asm/timex.h @@ -11,5 +11,6 @@ typedef unsigned long cycles_t; #define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; }) +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif diff --git a/arch/ia64/include/asm/timex.h b/arch/ia64/include/asm/timex.h index 869a3ac6bf23..7ccc077a60be 100644 --- a/arch/ia64/include/asm/timex.h +++ b/arch/ia64/include/asm/timex.h @@ -39,6 +39,7 @@ get_cycles (void) ret = ia64_getreg(_IA64_REG_AR_ITC); return ret; } +#define get_cycles get_cycles extern void ia64_cpu_local_tick (void); extern unsigned long long ia64_native_sched_clock (void); diff --git a/arch/m68k/include/asm/timex.h b/arch/m68k/include/asm/timex.h index 6a21d9358280..f4a7a340f4ca 100644 --- a/arch/m68k/include/asm/timex.h +++ b/arch/m68k/include/asm/timex.h @@ -35,7 +35,7 @@ static inline unsigned long random_get_entropy(void) { if (mach_random_get_entropy) return mach_random_get_entropy(); - return 0; + return random_get_entropy_fallback(); } #define random_get_entropy random_get_entropy diff --git a/arch/mips/include/asm/timex.h b/arch/mips/include/asm/timex.h index 8026baf46e72..2e107886f97a 100644 --- a/arch/mips/include/asm/timex.h +++ b/arch/mips/include/asm/timex.h @@ -76,25 +76,24 @@ static inline cycles_t get_cycles(void) else return 0; /* no usable counter */ } +#define get_cycles get_cycles /* * Like get_cycles - but where c0_count is not available we desperately * use c0_random in an attempt to get at least a little bit of entropy. - * - * R6000 and R6000A neither have a count register nor a random register. - * That leaves no entropy source in the CPU itself. */ static inline unsigned long random_get_entropy(void) { - unsigned int prid = read_c0_prid(); - unsigned int imp = prid & PRID_IMP_MASK; + unsigned int c0_random; - if (can_use_mips_counter(prid)) + if (can_use_mips_counter(read_c0_prid())) return read_c0_count(); - else if (likely(imp != PRID_IMP_R6000 && imp != PRID_IMP_R6000A)) - return read_c0_random(); + + if (cpu_has_3kex) + c0_random = (read_c0_random() >> 8) & 0x3f; else - return 0; /* no usable register */ + c0_random = read_c0_random() & 0x3f; + return (random_get_entropy_fallback() << 6) | (0x3f - c0_random); } #define random_get_entropy random_get_entropy diff --git a/arch/nios2/include/asm/timex.h b/arch/nios2/include/asm/timex.h index a769f871b28d..40a1adc9bd03 100644 --- a/arch/nios2/include/asm/timex.h +++ b/arch/nios2/include/asm/timex.h @@ -8,5 +8,8 @@ typedef unsigned long cycles_t; extern cycles_t get_cycles(void); +#define get_cycles get_cycles + +#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback()) #endif diff --git a/arch/openrisc/include/asm/timex.h b/arch/openrisc/include/asm/timex.h index d52b4e536e3f..5487fa93dd9b 100644 --- a/arch/openrisc/include/asm/timex.h +++ b/arch/openrisc/include/asm/timex.h @@ -23,6 +23,7 @@ static inline cycles_t get_cycles(void) { return mfspr(SPR_TTCR); } +#define get_cycles get_cycles /* This isn't really used any more */ #define CLOCK_TICK_RATE 1000 diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index 15f1b38dfe03..2fa6cefa62ca 100644 --- a/arch/openrisc/kernel/head.S +++ b/arch/openrisc/kernel/head.S @@ -521,6 +521,15 @@ _start: l.ori r3,r0,0x1 l.mtspr r0,r3,SPR_SR + /* + * Start the TTCR as early as possible, so that the RNG can make use of + * measurements of boot time from the earliest opportunity. Especially + * important is that the TTCR does not return zero by the time we reach + * random_init(). + */ + l.movhi r3,hi(SPR_TTMR_CR) + l.mtspr r0,r3,SPR_TTMR + CLEAR_GPR(r1) CLEAR_GPR(r2) CLEAR_GPR(r3) diff --git a/arch/parisc/include/asm/timex.h b/arch/parisc/include/asm/timex.h index 06b510f8172e..b4622cb06a75 100644 --- a/arch/parisc/include/asm/timex.h +++ b/arch/parisc/include/asm/timex.h @@ -13,9 +13,10 @@ typedef unsigned long cycles_t; -static inline cycles_t get_cycles (void) +static inline cycles_t get_cycles(void) { return mfctl(16); } +#define get_cycles get_cycles #endif diff --git a/arch/powerpc/include/asm/timex.h b/arch/powerpc/include/asm/timex.h index fa2e76e4093a..14b4489de52c 100644 --- a/arch/powerpc/include/asm/timex.h +++ b/arch/powerpc/include/asm/timex.h @@ -19,6 +19,7 @@ static inline cycles_t get_cycles(void) { return mftb(); } +#define get_cycles get_cycles #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_TIMEX_H */ diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h index 507cae273bc6..d6a7428f6248 100644 --- a/arch/riscv/include/asm/timex.h +++ b/arch/riscv/include/asm/timex.h @@ -41,7 +41,7 @@ static inline u32 get_cycles_hi(void) static inline unsigned long random_get_entropy(void) { if (unlikely(clint_time_val == NULL)) - return 0; + return random_get_entropy_fallback(); return get_cycles(); } #define random_get_entropy() random_get_entropy() diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index 2cfce42aa7fc..ce878e85b6e4 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -197,6 +197,7 @@ static inline cycles_t get_cycles(void) { return (cycles_t) get_tod_clock() >> 2; } +#define get_cycles get_cycles int get_phys_clock(unsigned long *clock); void init_cpu_timer(void); diff --git a/arch/sparc/include/asm/timex_32.h b/arch/sparc/include/asm/timex_32.h index 542915b46209..f86326a6f89e 100644 --- a/arch/sparc/include/asm/timex_32.h +++ b/arch/sparc/include/asm/timex_32.h @@ -9,8 +9,6 @@ #define CLOCK_TICK_RATE 1193180 /* Underlying HZ */ -/* XXX Maybe do something better at some point... -DaveM */ -typedef unsigned long cycles_t; -#define get_cycles() (0) +#include <asm-generic/timex.h> #endif diff --git a/arch/um/include/asm/timex.h b/arch/um/include/asm/timex.h index e392a9a5bc9b..9f27176adb26 100644 --- a/arch/um/include/asm/timex.h +++ b/arch/um/include/asm/timex.h @@ -2,13 +2,8 @@ #ifndef __UM_TIMEX_H #define __UM_TIMEX_H -typedef unsigned long cycles_t; - -static inline cycles_t get_cycles (void) -{ - return 0; -} - #define CLOCK_TICK_RATE (HZ) +#include <asm-generic/timex.h> + #endif diff --git a/arch/x86/include/asm/timex.h b/arch/x86/include/asm/timex.h index a4a8b1b16c0c..956e4145311b 100644 --- a/arch/x86/include/asm/timex.h +++ b/arch/x86/include/asm/timex.h @@ -5,6 +5,15 @@ #include <asm/processor.h> #include <asm/tsc.h> +static inline unsigned long random_get_entropy(void) +{ + if (!IS_ENABLED(CONFIG_X86_TSC) && + !cpu_feature_enabled(X86_FEATURE_TSC)) + return random_get_entropy_fallback(); + return rdtsc(); +} +#define random_get_entropy random_get_entropy + /* Assume we use the PIT time source for the clock tick */ #define CLOCK_TICK_RATE PIT_TICK_RATE diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index 01a300a9700b..fbdc3d951494 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -20,13 +20,12 @@ extern void disable_TSC(void); static inline cycles_t get_cycles(void) { -#ifndef CONFIG_X86_TSC - if (!boot_cpu_has(X86_FEATURE_TSC)) + if (!IS_ENABLED(CONFIG_X86_TSC) && + !cpu_feature_enabled(X86_FEATURE_TSC)) return 0; -#endif - return rdtsc(); } +#define get_cycles get_cycles extern struct system_counterval_t convert_art_to_tsc(u64 art); extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns); diff --git a/arch/xtensa/include/asm/timex.h b/arch/xtensa/include/asm/timex.h index 233ec75e60c6..3f2462f2d027 100644 --- a/arch/xtensa/include/asm/timex.h +++ b/arch/xtensa/include/asm/timex.h @@ -29,10 +29,6 @@ extern unsigned long ccount_freq; -typedef unsigned long long cycles_t; - -#define get_cycles() (0) - void local_timer_setup(unsigned cpu); /* @@ -59,4 +55,6 @@ static inline void set_linux_timer (unsigned long ccompare) xtensa_set_sr(ccompare, SREG_CCOMPARE + LINUX_TIMER); } +#include <asm-generic/timex.h> + #endif /* _XTENSA_TIMEX_H */ diff --git a/drivers/char/random.c b/drivers/char/random.c index 4c9adb4f3d5d..b691b9d59503 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -15,14 +15,12 @@ * - Sysctl interface. * * The high level overview is that there is one input pool, into which - * various pieces of data are hashed. Some of that data is then "credited" as - * having a certain number of bits of entropy. When enough bits of entropy are - * available, the hash is finalized and handed as a key to a stream cipher that - * expands it indefinitely for various consumers. This key is periodically - * refreshed as the various entropy collectors, described below, add data to the - * input pool and credit it. There is currently no Fortuna-like scheduler - * involved, which can lead to malicious entropy sources causing a premature - * reseed, and the entropy estimates are, at best, conservative guesses. + * various pieces of data are hashed. Prior to initialization, some of that + * data is then "credited" as having a certain number of bits of entropy. + * When enough bits of entropy are available, the hash is finalized and + * handed as a key to a stream cipher that expands it indefinitely for + * various consumers. This key is periodically refreshed as the various + * entropy collectors, described below, add data to the input pool. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -53,6 +51,8 @@ #include <linux/completion.h> #include <linux/uuid.h> #include <linux/uaccess.h> +#include <linux/suspend.h> +#include <linux/siphash.h> #include <crypto/chacha.h> #include <crypto/blake2s.h> #include <asm/processor.h> @@ -71,27 +71,25 @@ *********************************************************************/ /* - * crng_init = 0 --> Uninitialized - * 1 --> Initialized - * 2 --> Initialized from input_pool - * * crng_init is protected by base_crng->lock, and only increases - * its value (from 0->1->2). + * its value (from empty->early->ready). */ -static int crng_init = 0; -#define crng_ready() (likely(crng_init > 1)) -/* Various types of waiters for crng_init->2 transition. */ +static enum { + CRNG_EMPTY = 0, /* Little to no entropy collected */ + CRNG_EARLY = 1, /* At least POOL_EARLY_BITS collected */ + CRNG_READY = 2 /* Fully initialized with POOL_READY_BITS collected */ +} crng_init __read_mostly = CRNG_EMPTY; +static DEFINE_STATIC_KEY_FALSE(crng_is_ready); +#define crng_ready() (static_branch_likely(&crng_is_ready) || crng_init >= CRNG_READY) +/* Various types of waiters for crng_init->CRNG_READY transition. */ static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); static struct fasync_struct *fasync; -static DEFINE_SPINLOCK(random_ready_chain_lock); -static RAW_NOTIFIER_HEAD(random_ready_chain); /* Control how we warn userspace. */ -static struct ratelimit_state unseeded_warning = - RATELIMIT_STATE_INIT("warn_unseeded_randomness", HZ, 3); static struct ratelimit_state urandom_warning = RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3); -static int ratelimit_disable __read_mostly; +static int ratelimit_disable __read_mostly = + IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM); module_param_named(ratelimit_disable, ratelimit_disable, int, 0644); MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression"); @@ -110,6 +108,11 @@ bool rng_is_initialized(void) } EXPORT_SYMBOL(rng_is_initialized); +static void __cold crng_set_ready(struct work_struct *work) +{ + static_branch_enable(&crng_is_ready); +} + /* Used by wait_for_random_bytes(), and considered an entropy collector, below. */ static void try_to_generate_entropy(void); @@ -137,73 +140,10 @@ int wait_for_random_bytes(void) } EXPORT_SYMBOL(wait_for_random_bytes); -/* - * Add a callback function that will be invoked when the input - * pool is initialised. - * - * returns: 0 if callback is successfully added - * -EALREADY if pool is already initialised (callback not called) - */ -int register_random_ready_notifier(struct notifier_block *nb) -{ - unsigned long flags; - int ret = -EALREADY; - - if (crng_ready()) - return ret; - - spin_lock_irqsave(&random_ready_chain_lock, flags); - if (!crng_ready()) - ret = raw_notifier_chain_register(&random_ready_chain, nb); - spin_unlock_irqrestore(&random_ready_chain_lock, flags); - return ret; -} - -/* - * Delete a previously registered readiness callback function. - */ -int unregister_random_ready_notifier(struct notifier_block *nb) -{ - unsigned long flags; - int ret; - - spin_lock_irqsave(&random_ready_chain_lock, flags); - ret = raw_notifier_chain_unregister(&random_ready_chain, nb); - spin_unlock_irqrestore(&random_ready_chain_lock, flags); - return ret; -} - -static void process_random_ready_list(void) -{ - unsigned long flags; - - spin_lock_irqsave(&random_ready_chain_lock, flags); - raw_notifier_call_chain(&random_ready_chain, 0, NULL); - spin_unlock_irqrestore(&random_ready_chain_lock, flags); -} - -#define warn_unseeded_randomness(previous) \ - _warn_unseeded_randomness(__func__, (void *)_RET_IP_, (previous)) - -static void _warn_unseeded_randomness(const char *func_name, void *caller, void **previous) -{ -#ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM - const bool print_once = false; -#else - static bool print_once __read_mostly; -#endif - - if (print_once || crng_ready() || - (previous && (caller == READ_ONCE(*previous)))) - return; - WRITE_ONCE(*previous, caller); -#ifndef CONFIG_WARN_ALL_UNSEEDED_RANDOM - print_once = true; -#endif - if (__ratelimit(&unseeded_warning)) - printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", - func_name, caller, crng_init); -} +#define warn_unseeded_randomness() \ + if (IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM) && !crng_ready()) \ + printk_deferred(KERN_NOTICE "random: %s called from %pS with crng_init=%d\n", \ + __func__, (void *)_RET_IP_, crng_init) /********************************************************************* @@ -216,7 +156,7 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, void * * There are a few exported interfaces for use by other drivers: * - * void get_random_bytes(void *buf, size_t nbytes) + * void get_random_bytes(void *buf, size_t len) * u32 get_random_u32() * u64 get_random_u64() * unsigned int get_random_int() @@ -232,8 +172,8 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, void *********************************************************************/ enum { - CRNG_RESEED_INTERVAL = 300 * HZ, - CRNG_INIT_CNT_THRESH = 2 * CHACHA_KEY_SIZE + CRNG_RESEED_START_INTERVAL = HZ, + CRNG_RESEED_INTERVAL = 60 * HZ }; static struct { @@ -256,24 +196,17 @@ static DEFINE_PER_CPU(struct crng, crngs) = { .lock = INIT_LOCAL_LOCK(crngs.lock), }; -/* Used by crng_reseed() to extract a new seed from the input pool. */ -static bool drain_entropy(void *buf, size_t nbytes, bool force); +/* Used by crng_reseed() and crng_make_state() to extract a new seed from the input pool. */ +static void extract_entropy(void *buf, size_t len); -/* - * This extracts a new crng key from the input pool, but only if there is a - * sufficient amount of entropy available or force is true, in order to - * mitigate bruteforcing of newly added bits. - */ -static void crng_reseed(bool force) +/* This extracts a new crng key from the input pool. */ +static void crng_reseed(void) { unsigned long flags; unsigned long next_gen; u8 key[CHACHA_KEY_SIZE]; - bool finalize_init = false; - /* Only reseed if we can, to prevent brute forcing a small amount of new bits. */ - if (!drain_entropy(key, sizeof(key), force)) - return; + extract_entropy(key, sizeof(key)); /* * We copy the new key into the base_crng, overwriting the old one, @@ -288,28 +221,10 @@ static void crng_reseed(bool force) ++next_gen; WRITE_ONCE(base_crng.generation, next_gen); WRITE_ONCE(base_crng.birth, jiffies); - if (!crng_ready()) { - crng_init = 2; - finalize_init = true; - } + if (!static_branch_likely(&crng_is_ready)) + crng_init = CRNG_READY; spin_unlock_irqrestore(&base_crng.lock, flags); memzero_explicit(key, sizeof(key)); - if (finalize_init) { - process_random_ready_list(); - wake_up_interruptible(&crng_init_wait); - kill_fasync(&fasync, SIGIO, POLL_IN); - pr_notice("crng init done\n"); - if (unseeded_warning.missed) { - pr_notice("%d get_random_xx warning(s) missed due to ratelimiting\n", - unseeded_warning.missed); - unseeded_warning.missed = 0; - } - if (urandom_warning.missed) { - pr_notice("%d urandom warning(s) missed due to ratelimiting\n", - urandom_warning.missed); - urandom_warning.missed = 0; - } - } } /* @@ -345,10 +260,10 @@ static void crng_fast_key_erasure(u8 key[CHACHA_KEY_SIZE], } /* - * Return whether the crng seed is considered to be sufficiently - * old that a reseeding might be attempted. This happens if the last - * reseeding was CRNG_RESEED_INTERVAL ago, or during early boot, at - * an interval proportional to the uptime. + * Return whether the crng seed is considered to be sufficiently old + * that a reseeding is needed. This happens if the last reseeding + * was CRNG_RESEED_INTERVAL ago, or during early boot, at an interval + * proportional to the uptime. */ static bool crng_has_old_seed(void) { @@ -360,10 +275,10 @@ static bool crng_has_old_seed(void) if (uptime >= CRNG_RESEED_INTERVAL / HZ * 2) WRITE_ONCE(early_boot, false); else - interval = max_t(unsigned int, 5 * HZ, + interval = max_t(unsigned int, CRNG_RESEED_START_INTERVAL, (unsigned int)uptime / 2 * HZ); } - return time_after(jiffies, READ_ONCE(base_crng.birth) + interval); + return time_is_before_jiffies(READ_ONCE(base_crng.birth) + interval); } /* @@ -382,28 +297,31 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS], /* * For the fast path, we check whether we're ready, unlocked first, and * then re-check once locked later. In the case where we're really not - * ready, we do fast key erasure with the base_crng directly, because - * this is what crng_pre_init_inject() mutates during early init. + * ready, we do fast key erasure with the base_crng directly, extracting + * when crng_init is CRNG_EMPTY. */ if (!crng_ready()) { bool ready; spin_lock_irqsave(&base_crng.lock, flags); ready = crng_ready(); - if (!ready) + if (!ready) { + if (crng_init == CRNG_EMPTY) + extract_entropy(base_crng.key, sizeof(base_crng.key)); crng_fast_key_erasure(base_crng.key, chacha_state, random_data, random_data_len); + } spin_unlock_irqrestore(&base_crng.lock, flags); if (!ready) return; } /* - * If the base_crng is old enough, we try to reseed, which in turn - * bumps the generation counter that we check below. + * If the base_crng is old enough, we reseed, which in turn bumps the + * generation counter that we check below. */ if (unlikely(crng_has_old_seed())) - crng_reseed(false); + crng_reseed(); local_lock_irqsave(&crngs.lock, flags); crng = raw_cpu_ptr(&crngs); @@ -433,68 +351,24 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS], local_unlock_irqrestore(&crngs.lock, flags); } -/* - * This function is for crng_init == 0 only. It loads entropy directly - * into the crng's key, without going through the input pool. It is, - * generally speaking, not very safe, but we use this only at early - * boot time when it's better to have something there rather than - * nothing. - * - * If account is set, then the crng_init_cnt counter is incremented. - * This shouldn't be set by functions like add_device_randomness(), - * where we can't trust the buffer passed to it is guaranteed to be - * unpredictable (so it might not have any entropy at all). - */ -static void crng_pre_init_inject(const void *input, size_t len, bool account) -{ - static int crng_init_cnt = 0; - struct blake2s_state hash; - unsigned long flags; - - blake2s_init(&hash, sizeof(base_crng.key)); - - spin_lock_irqsave(&base_crng.lock, flags); - if (crng_init != 0) { - spin_unlock_irqrestore(&base_crng.lock, flags); - return; - } - - blake2s_update(&hash, base_crng.key, sizeof(base_crng.key)); - blake2s_update(&hash, input, len); - blake2s_final(&hash, base_crng.key); - - if (account) { - crng_init_cnt += min_t(size_t, len, CRNG_INIT_CNT_THRESH - crng_init_cnt); - if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) { - ++base_crng.generation; - crng_init = 1; - } - } - - spin_unlock_irqrestore(&base_crng.lock, flags); - - if (crng_init == 1) - pr_notice("fast init done\n"); -} - -static void _get_random_bytes(void *buf, size_t nbytes) +static void _get_random_bytes(void *buf, size_t len) { u32 chacha_state[CHACHA_STATE_WORDS]; u8 tmp[CHACHA_BLOCK_SIZE]; - size_t len; + size_t first_block_len; - if (!nbytes) + if (!len) return; - len = min_t(size_t, 32, nbytes); - crng_make_state(chacha_state, buf, len); - nbytes -= len; - buf += len; + first_block_len = min_t(size_t, 32, len); + crng_make_state(chacha_state, buf, first_block_len); + len -= first_block_len; + buf += first_block_len; - while (nbytes) { - if (nbytes < CHACHA_BLOCK_SIZE) { + while (len) { + if (len < CHACHA_BLOCK_SIZE) { chacha20_block(chacha_state, tmp); - memcpy(buf, tmp, nbytes); + memcpy(buf, tmp, len); memzero_explicit(tmp, sizeof(tmp)); break; } @@ -502,7 +376,7 @@ static void _get_random_bytes(void *buf, size_t nbytes) chacha20_block(chacha_state, buf); if (unlikely(chacha_state[12] == 0)) ++chacha_state[13]; - nbytes -= CHACHA_BLOCK_SIZE; + len -= CHACHA_BLOCK_SIZE; buf += CHACHA_BLOCK_SIZE; } @@ -512,29 +386,24 @@ static void _get_random_bytes(void *buf, size_t nbytes) /* * This function is the exported kernel interface. It returns some * number of good random numbers, suitable for key generation, seeding - * TCP sequence numbers, etc. It does not rely on the hardware random - * number generator. For random bytes direct from the hardware RNG - * (when available), use get_random_bytes_arch(). In order to ensure - * that the randomness provided by this function is okay, the function - * wait_for_random_bytes() should be called and return 0 at least once - * at any point prior. + * TCP sequence numbers, etc. In order to ensure that the randomness + * by this function is okay, the function wait_for_random_bytes() + * should be called and return 0 at least once at any point prior. */ -void get_random_bytes(void *buf, size_t nbytes) +void get_random_bytes(void *buf, size_t len) { - static void *previous; - - warn_unseeded_randomness(&previous); - _get_random_bytes(buf, nbytes); + warn_unseeded_randomness(); + _get_random_bytes(buf, len); } EXPORT_SYMBOL(get_random_bytes); -static ssize_t get_random_bytes_user(void __user *buf, size_t nbytes) +static ssize_t get_random_bytes_user(struct iov_iter *iter) { - size_t len, left, ret = 0; u32 chacha_state[CHACHA_STATE_WORDS]; - u8 output[CHACHA_BLOCK_SIZE]; + u8 block[CHACHA_BLOCK_SIZE]; + size_t ret = 0, copied; - if (!nbytes) + if (unlikely(!iov_iter_count(iter))) return 0; /* @@ -548,30 +417,22 @@ static ssize_t get_random_bytes_user(void __user *buf, size_t nbytes) * use chacha_state after, so we can simply return those bytes to * the user directly. */ - if (nbytes <= CHACHA_KEY_SIZE) { - ret = nbytes - copy_to_user(buf, &chacha_state[4], nbytes); + if (iov_iter_count(iter) <= CHACHA_KEY_SIZE) { + ret = copy_to_iter(&chacha_state[4], CHACHA_KEY_SIZE, iter); goto out_zero_chacha; } for (;;) { - chacha20_block(chacha_state, output); + chacha20_block(chacha_state, block); if (unlikely(chacha_state[12] == 0)) ++chacha_state[13]; - len = min_t(size_t, nbytes, CHACHA_BLOCK_SIZE); - left = copy_to_user(buf, output, len); |