145 lines
3.4 KiB
C
145 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright IBM Corp. 2019
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*/
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#include <asm/mem_detect.h>
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#include <asm/cpacf.h>
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#include <asm/timex.h>
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#include <asm/sclp.h>
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#include "compressed/decompressor.h"
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#define PRNG_MODE_TDES 1
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#define PRNG_MODE_SHA512 2
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#define PRNG_MODE_TRNG 3
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struct prno_parm {
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u32 res;
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u32 reseed_counter;
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u64 stream_bytes;
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u8 V[112];
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u8 C[112];
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};
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struct prng_parm {
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u8 parm_block[32];
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u32 reseed_counter;
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u64 byte_counter;
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};
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static int check_prng(void)
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{
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if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) {
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sclp_early_printk("KASLR disabled: CPU has no PRNG\n");
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return 0;
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}
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if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
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return PRNG_MODE_TRNG;
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if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN))
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return PRNG_MODE_SHA512;
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else
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return PRNG_MODE_TDES;
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}
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static unsigned long get_random(unsigned long limit)
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{
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struct prng_parm prng = {
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/* initial parameter block for tdes mode, copied from libica */
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.parm_block = {
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0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
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0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
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0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
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0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0
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},
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};
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unsigned long seed, random;
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struct prno_parm prno;
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__u64 entropy[4];
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int mode, i;
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mode = check_prng();
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seed = get_tod_clock_fast();
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switch (mode) {
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case PRNG_MODE_TRNG:
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cpacf_trng(NULL, 0, (u8 *) &random, sizeof(random));
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break;
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case PRNG_MODE_SHA512:
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cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, &prno, NULL, 0,
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(u8 *) &seed, sizeof(seed));
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cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prno, (u8 *) &random,
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sizeof(random), NULL, 0);
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break;
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case PRNG_MODE_TDES:
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/* add entropy */
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*(unsigned long *) prng.parm_block ^= seed;
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for (i = 0; i < 16; i++) {
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cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block,
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(char *) entropy, (char *) entropy,
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sizeof(entropy));
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memcpy(prng.parm_block, entropy, sizeof(entropy));
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}
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random = seed;
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cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) &random,
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(u8 *) &random, sizeof(random));
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break;
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default:
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random = 0;
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}
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return random % limit;
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}
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unsigned long get_random_base(unsigned long safe_addr)
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{
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unsigned long base, start, end, kernel_size;
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unsigned long block_sum, offset;
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int i;
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if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE) {
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if (safe_addr < INITRD_START + INITRD_SIZE)
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safe_addr = INITRD_START + INITRD_SIZE;
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}
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safe_addr = ALIGN(safe_addr, THREAD_SIZE);
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kernel_size = vmlinux.image_size + vmlinux.bss_size;
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block_sum = 0;
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for_each_mem_detect_block(i, &start, &end) {
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if (memory_end_set) {
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if (start >= memory_end)
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break;
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if (end > memory_end)
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end = memory_end;
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}
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if (end - start < kernel_size)
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continue;
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block_sum += end - start - kernel_size;
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}
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if (!block_sum) {
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sclp_early_printk("KASLR disabled: not enough memory\n");
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return 0;
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}
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base = get_random(block_sum);
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if (base == 0)
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return 0;
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if (base < safe_addr)
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base = safe_addr;
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block_sum = offset = 0;
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for_each_mem_detect_block(i, &start, &end) {
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if (memory_end_set) {
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if (start >= memory_end)
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break;
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if (end > memory_end)
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end = memory_end;
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}
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if (end - start < kernel_size)
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continue;
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block_sum += end - start - kernel_size;
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if (base <= block_sum) {
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base = start + base - offset;
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base = ALIGN_DOWN(base, THREAD_SIZE);
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break;
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}
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offset = block_sum;
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}
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return base;
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}
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