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Random number generator fixes for Linux 5.19-rc2.
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This commit is contained in:
Linus Torvalds
commit
3cae0d8475
@ -429,28 +429,40 @@ config ADI
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driver include crash and makedumpfile.
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config RANDOM_TRUST_CPU
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bool "Trust the CPU manufacturer to initialize Linux's CRNG"
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bool "Initialize RNG using CPU RNG instructions"
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default y
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depends on ARCH_RANDOM
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default n
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help
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Assume that CPU manufacturer (e.g., Intel or AMD for RDSEED or
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RDRAND, IBM for the S390 and Power PC architectures) is trustworthy
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for the purposes of initializing Linux's CRNG. Since this is not
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something that can be independently audited, this amounts to trusting
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that CPU manufacturer (perhaps with the insistence or mandate
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of a Nation State's intelligence or law enforcement agencies)
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has not installed a hidden back door to compromise the CPU's
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random number generation facilities. This can also be configured
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at boot with "random.trust_cpu=on/off".
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Initialize the RNG using random numbers supplied by the CPU's
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RNG instructions (e.g. RDRAND), if supported and available. These
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random numbers are never used directly, but are rather hashed into
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the main input pool, and this happens regardless of whether or not
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this option is enabled. Instead, this option controls whether the
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they are credited and hence can initialize the RNG. Additionally,
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other sources of randomness are always used, regardless of this
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setting. Enabling this implies trusting that the CPU can supply high
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quality and non-backdoored random numbers.
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Say Y here unless you have reason to mistrust your CPU or believe
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its RNG facilities may be faulty. This may also be configured at
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boot time with "random.trust_cpu=on/off".
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config RANDOM_TRUST_BOOTLOADER
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bool "Trust the bootloader to initialize Linux's CRNG"
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bool "Initialize RNG using bootloader-supplied seed"
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default y
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help
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Some bootloaders can provide entropy to increase the kernel's initial
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device randomness. Say Y here to assume the entropy provided by the
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booloader is trustworthy so it will be added to the kernel's entropy
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pool. Otherwise, say N here so it will be regarded as device input that
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only mixes the entropy pool. This can also be configured at boot with
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"random.trust_bootloader=on/off".
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Initialize the RNG using a seed supplied by the bootloader or boot
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environment (e.g. EFI or a bootloader-generated device tree). This
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seed is not used directly, but is rather hashed into the main input
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pool, and this happens regardless of whether or not this option is
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enabled. Instead, this option controls whether the seed is credited
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and hence can initialize the RNG. Additionally, other sources of
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randomness are always used, regardless of this setting. Enabling
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this implies trusting that the bootloader can supply high quality and
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non-backdoored seeds.
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Say Y here unless you have reason to mistrust your bootloader or
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believe its RNG facilities may be faulty. This may also be configured
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at boot time with "random.trust_bootloader=on/off".
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endmenu
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@ -650,7 +650,8 @@ static void __cold _credit_init_bits(size_t bits)
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if (orig < POOL_READY_BITS && new >= POOL_READY_BITS) {
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crng_reseed(); /* Sets crng_init to CRNG_READY under base_crng.lock. */
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execute_in_process_context(crng_set_ready, &set_ready);
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if (static_key_initialized)
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execute_in_process_context(crng_set_ready, &set_ready);
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wake_up_interruptible(&crng_init_wait);
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kill_fasync(&fasync, SIGIO, POLL_IN);
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pr_notice("crng init done\n");
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@ -724,9 +725,8 @@ static void __cold _credit_init_bits(size_t bits)
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*
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**********************************************************************/
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static bool used_arch_random;
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static bool trust_cpu __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU);
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static bool trust_bootloader __ro_after_init = IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER);
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static bool trust_cpu __initdata = IS_ENABLED(CONFIG_RANDOM_TRUST_CPU);
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static bool trust_bootloader __initdata = IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER);
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static int __init parse_trust_cpu(char *arg)
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{
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return kstrtobool(arg, &trust_cpu);
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@ -776,7 +776,7 @@ static struct notifier_block pm_notifier = { .notifier_call = random_pm_notifica
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int __init random_init(const char *command_line)
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{
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ktime_t now = ktime_get_real();
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unsigned int i, arch_bytes;
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unsigned int i, arch_bits;
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unsigned long entropy;
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#if defined(LATENT_ENTROPY_PLUGIN)
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@ -784,12 +784,12 @@ int __init random_init(const char *command_line)
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_mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed));
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#endif
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for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE;
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for (i = 0, arch_bits = BLAKE2S_BLOCK_SIZE * 8;
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i < BLAKE2S_BLOCK_SIZE; i += sizeof(entropy)) {
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if (!arch_get_random_seed_long_early(&entropy) &&
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!arch_get_random_long_early(&entropy)) {
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entropy = random_get_entropy();
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arch_bytes -= sizeof(entropy);
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arch_bits -= sizeof(entropy) * 8;
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}
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_mix_pool_bytes(&entropy, sizeof(entropy));
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}
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@ -798,11 +798,18 @@ int __init random_init(const char *command_line)
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_mix_pool_bytes(command_line, strlen(command_line));
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add_latent_entropy();
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/*
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* If we were initialized by the bootloader before jump labels are
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* initialized, then we should enable the static branch here, where
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* it's guaranteed that jump labels have been initialized.
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*/
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if (!static_branch_likely(&crng_is_ready) && crng_init >= CRNG_READY)
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crng_set_ready(NULL);
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if (crng_ready())
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crng_reseed();
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else if (trust_cpu)
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credit_init_bits(arch_bytes * 8);
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used_arch_random = arch_bytes * 8 >= POOL_READY_BITS;
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_credit_init_bits(arch_bits);
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WARN_ON(register_pm_notifier(&pm_notifier));
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@ -811,17 +818,6 @@ int __init random_init(const char *command_line)
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return 0;
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}
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/*
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* Returns whether arch randomness has been mixed into the initial
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* state of the RNG, regardless of whether or not that randomness
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* was credited. Knowing this is only good for a very limited set
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* of uses, such as early init printk pointer obfuscation.
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*/
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bool rng_has_arch_random(void)
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{
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return used_arch_random;
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}
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/*
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* Add device- or boot-specific data to the input pool to help
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* initialize it.
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@ -865,13 +861,12 @@ EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
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* Handle random seed passed by bootloader, and credit it if
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* CONFIG_RANDOM_TRUST_BOOTLOADER is set.
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*/
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void __cold add_bootloader_randomness(const void *buf, size_t len)
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void __init add_bootloader_randomness(const void *buf, size_t len)
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{
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mix_pool_bytes(buf, len);
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if (trust_bootloader)
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credit_init_bits(len * 8);
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}
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EXPORT_SYMBOL_GPL(add_bootloader_randomness);
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#if IS_ENABLED(CONFIG_VMGENID)
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static BLOCKING_NOTIFIER_HEAD(vmfork_chain);
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@ -4,7 +4,7 @@
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*
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* Implements the standard CRC ITU-T V.41:
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* Width 16
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* Poly 0x1021 (x^16 + x^12 + x^15 + 1)
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* Poly 0x1021 (x^16 + x^12 + x^5 + 1)
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* Init 0
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*/
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@ -13,7 +13,7 @@
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struct notifier_block;
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void add_device_randomness(const void *buf, size_t len);
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void add_bootloader_randomness(const void *buf, size_t len);
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void __init add_bootloader_randomness(const void *buf, size_t len);
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void add_input_randomness(unsigned int type, unsigned int code,
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unsigned int value) __latent_entropy;
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void add_interrupt_randomness(int irq) __latent_entropy;
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@ -74,7 +74,6 @@ static inline unsigned long get_random_canary(void)
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int __init random_init(const char *command_line);
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bool rng_is_initialized(void);
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bool rng_has_arch_random(void);
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int wait_for_random_bytes(void);
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/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
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@ -7,7 +7,7 @@
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#include <linux/module.h>
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#include <linux/crc-itu-t.h>
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/** CRC table for the CRC ITU-T V.41 0x1021 (x^16 + x^12 + x^15 + 1) */
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/* CRC table for the CRC ITU-T V.41 0x1021 (x^16 + x^12 + x^5 + 1) */
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const u16 crc_itu_t_table[256] = {
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
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0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
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@ -769,8 +769,7 @@ static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
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static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
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unsigned long flags;
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if (!system_unbound_wq ||
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(!rng_is_initialized() && !rng_has_arch_random()) ||
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if (!system_unbound_wq || !rng_is_initialized() ||
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!spin_trylock_irqsave(&filling, flags))
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return -EAGAIN;
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@ -64,8 +64,8 @@ QEMU_VPORT_RESULT := virtio-serial-device
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host -machine virt,gic_version=host,accel=kvm
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else
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QEMU_MACHINE := -cpu cortex-a53 -machine virt
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CFLAGS += -march=armv8-a -mtune=cortex-a53
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QEMU_MACHINE := -cpu max -machine virt
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CFLAGS += -march=armv8-a
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endif
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else ifeq ($(ARCH),aarch64_be)
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CHOST := aarch64_be-linux-musl
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@ -76,8 +76,8 @@ QEMU_VPORT_RESULT := virtio-serial-device
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host -machine virt,gic_version=host,accel=kvm
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else
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QEMU_MACHINE := -cpu cortex-a53 -machine virt
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CFLAGS += -march=armv8-a -mtune=cortex-a53
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QEMU_MACHINE := -cpu max -machine virt
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CFLAGS += -march=armv8-a
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endif
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else ifeq ($(ARCH),arm)
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CHOST := arm-linux-musleabi
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@ -88,8 +88,8 @@ QEMU_VPORT_RESULT := virtio-serial-device
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host -machine virt,gic_version=host,accel=kvm
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else
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QEMU_MACHINE := -cpu cortex-a15 -machine virt
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CFLAGS += -march=armv7-a -mtune=cortex-a15 -mabi=aapcs-linux
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QEMU_MACHINE := -cpu max -machine virt
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CFLAGS += -march=armv7-a -mabi=aapcs-linux
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endif
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else ifeq ($(ARCH),armeb)
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CHOST := armeb-linux-musleabi
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@ -100,8 +100,8 @@ QEMU_VPORT_RESULT := virtio-serial-device
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host -machine virt,gic_version=host,accel=kvm
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else
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QEMU_MACHINE := -cpu cortex-a15 -machine virt
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CFLAGS += -march=armv7-a -mabi=aapcs-linux # We don't pass -mtune=cortex-a15 due to a compiler bug on big endian.
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QEMU_MACHINE := -cpu max -machine virt
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CFLAGS += -march=armv7-a -mabi=aapcs-linux
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LDFLAGS += -Wl,--be8
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endif
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else ifeq ($(ARCH),x86_64)
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@ -112,8 +112,7 @@ KERNEL_BZIMAGE := $(KERNEL_BUILD_PATH)/arch/x86/boot/bzImage
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host -machine q35,accel=kvm
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else
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QEMU_MACHINE := -cpu Skylake-Server -machine q35
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CFLAGS += -march=skylake-avx512
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QEMU_MACHINE := -cpu max -machine q35
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endif
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else ifeq ($(ARCH),i686)
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CHOST := i686-linux-musl
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@ -123,8 +122,7 @@ KERNEL_BZIMAGE := $(KERNEL_BUILD_PATH)/arch/x86/boot/bzImage
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ifeq ($(subst x86_64,i686,$(HOST_ARCH)),$(ARCH))
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QEMU_MACHINE := -cpu host -machine q35,accel=kvm
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else
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QEMU_MACHINE := -cpu coreduo -machine q35
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CFLAGS += -march=prescott
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QEMU_MACHINE := -cpu max -machine q35
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endif
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else ifeq ($(ARCH),mips64)
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CHOST := mips64-linux-musl
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@ -182,7 +180,7 @@ KERNEL_BZIMAGE := $(KERNEL_BUILD_PATH)/vmlinux
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ifeq ($(HOST_ARCH),$(ARCH))
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QEMU_MACHINE := -cpu host,accel=kvm -machine pseries
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else
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QEMU_MACHINE := -machine pseries
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QEMU_MACHINE := -machine pseries -device spapr-rng,rng=rng -object rng-random,id=rng
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endif
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else ifeq ($(ARCH),powerpc64le)
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CHOST := powerpc64le-linux-musl
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@ -192,7 +190,7 @@ KERNEL_BZIMAGE := $(KERNEL_BUILD_PATH)/vmlinux
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ifeq ($(HOST_ARCH),$(ARCH))
|
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QEMU_MACHINE := -cpu host,accel=kvm -machine pseries
|
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else
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QEMU_MACHINE := -machine pseries
|
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QEMU_MACHINE := -machine pseries -device spapr-rng,rng=rng -object rng-random,id=rng
|
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endif
|
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else ifeq ($(ARCH),powerpc)
|
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CHOST := powerpc-linux-musl
|
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@ -247,7 +245,7 @@ QEMU_VPORT_RESULT := virtio-serial-ccw
|
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ifeq ($(HOST_ARCH),$(ARCH))
|
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QEMU_MACHINE := -cpu host,accel=kvm -machine s390-ccw-virtio -append $(KERNEL_CMDLINE)
|
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else
|
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QEMU_MACHINE := -machine s390-ccw-virtio -append $(KERNEL_CMDLINE)
|
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QEMU_MACHINE := -cpu max -machine s390-ccw-virtio -append $(KERNEL_CMDLINE)
|
||||
endif
|
||||
else
|
||||
$(error I only build: x86_64, i686, arm, armeb, aarch64, aarch64_be, mips, mipsel, mips64, mips64el, powerpc64, powerpc64le, powerpc, m68k, riscv64, riscv32, s390x)
|
||||
|
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@ -21,6 +21,7 @@
|
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#include <sys/utsname.h>
|
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#include <sys/sendfile.h>
|
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#include <sys/sysmacros.h>
|
||||
#include <sys/random.h>
|
||||
#include <linux/random.h>
|
||||
#include <linux/version.h>
|
||||
|
||||
@ -58,6 +59,8 @@ static void seed_rng(void)
|
||||
{
|
||||
int bits = 256, fd;
|
||||
|
||||
if (!getrandom(NULL, 0, GRND_NONBLOCK))
|
||||
return;
|
||||
pretty_message("[+] Fake seeding RNG...");
|
||||
fd = open("/dev/random", O_WRONLY);
|
||||
if (fd < 0)
|
||||
|
||||
@ -31,6 +31,7 @@ CONFIG_TTY=y
|
||||
CONFIG_BINFMT_ELF=y
|
||||
CONFIG_BINFMT_SCRIPT=y
|
||||
CONFIG_VDSO=y
|
||||
CONFIG_STRICT_KERNEL_RWX=y
|
||||
CONFIG_VIRTUALIZATION=y
|
||||
CONFIG_HYPERVISOR_GUEST=y
|
||||
CONFIG_PARAVIRT=y
|
||||
@ -65,6 +66,8 @@ CONFIG_PROC_FS=y
|
||||
CONFIG_PROC_SYSCTL=y
|
||||
CONFIG_SYSFS=y
|
||||
CONFIG_TMPFS=y
|
||||
CONFIG_RANDOM_TRUST_CPU=y
|
||||
CONFIG_RANDOM_TRUST_BOOTLOADER=y
|
||||
CONFIG_CONSOLE_LOGLEVEL_DEFAULT=15
|
||||
CONFIG_LOG_BUF_SHIFT=18
|
||||
CONFIG_PRINTK_TIME=y
|
||||
|
||||
Loading…
Reference in New Issue
Block a user