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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | // SPDX-License-Identifier: GPL-2.0 /* * Copyright IBM Corp. 2019 */ #include <linux/pgtable.h> #include <asm/physmem_info.h> #include <asm/cpacf.h> #include <asm/timex.h> #include <asm/sclp.h> #include <asm/kasan.h> #include "decompressor.h" #include "boot.h" #define PRNG_MODE_TDES 1 #define PRNG_MODE_SHA512 2 #define PRNG_MODE_TRNG 3 struct prno_parm { u32 res; u32 reseed_counter; u64 stream_bytes; u8 V[112]; u8 C[112]; }; struct prng_parm { u8 parm_block[32]; u32 reseed_counter; u64 byte_counter; }; static int check_prng(void) { if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) { sclp_early_printk("KASLR disabled: CPU has no PRNG\n"); return 0; } if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG)) return PRNG_MODE_TRNG; if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN)) return PRNG_MODE_SHA512; else return PRNG_MODE_TDES; } static int get_random(unsigned long limit, unsigned long *value) { struct prng_parm prng = { /* initial parameter block for tdes mode, copied from libica */ .parm_block = { 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52, 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4, 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF, 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0 }, }; unsigned long seed, random; struct prno_parm prno; __u64 entropy[4]; int mode, i; mode = check_prng(); seed = get_tod_clock_fast(); switch (mode) { case PRNG_MODE_TRNG: cpacf_trng(NULL, 0, (u8 *) &random, sizeof(random)); break; case PRNG_MODE_SHA512: cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, &prno, NULL, 0, (u8 *) &seed, sizeof(seed)); cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prno, (u8 *) &random, sizeof(random), NULL, 0); break; case PRNG_MODE_TDES: /* add entropy */ *(unsigned long *) prng.parm_block ^= seed; for (i = 0; i < 16; i++) { cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) entropy, (u8 *) entropy, sizeof(entropy)); memcpy(prng.parm_block, entropy, sizeof(entropy)); } random = seed; cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) &random, (u8 *) &random, sizeof(random)); break; default: return -1; } *value = random % limit; return 0; } static void sort_reserved_ranges(struct reserved_range *res, unsigned long size) { struct reserved_range tmp; int i, j; for (i = 1; i < size; i++) { tmp = res[i]; for (j = i - 1; j >= 0 && res[j].start > tmp.start; j--) res[j + 1] = res[j]; res[j + 1] = tmp; } } static unsigned long iterate_valid_positions(unsigned long size, unsigned long align, unsigned long _min, unsigned long _max, struct reserved_range *res, size_t res_count, bool pos_count, unsigned long find_pos) { unsigned long start, end, tmp_end, range_pos, pos = 0; struct reserved_range *res_end = res + res_count; struct reserved_range *skip_res; int i; align = max(align, 8UL); _min = round_up(_min, align); for_each_physmem_usable_range(i, &start, &end) { if (_min >= end) continue; start = round_up(start, align); if (start >= _max) break; start = max(_min, start); end = min(_max, end); while (start + size <= end) { /* skip reserved ranges below the start */ while (res && res->end <= start) { res++; if (res >= res_end) res = NULL; } skip_res = NULL; tmp_end = end; /* has intersecting reserved range */ if (res && res->start < end) { skip_res = res; tmp_end = res->start; } if (start + size <= tmp_end) { range_pos = (tmp_end - start - size) / align + 1; if (pos_count) { pos += range_pos; } else { if (range_pos >= find_pos) return start + (find_pos - 1) * align; find_pos -= range_pos; } } if (!skip_res) break; start = round_up(skip_res->end, align); } } return pos_count ? pos : 0; } /* * Two types of decompressor memory allocations/reserves are considered * differently. * * "Static" or "single" allocations are done via physmem_alloc_range() and * physmem_reserve(), and they are listed in physmem_info.reserved[]. Each * type of "static" allocation can only have one allocation per type and * cannot have chains. * * On the other hand, "dynamic" or "repetitive" allocations are done via * physmem_alloc_top_down(). These allocations are tightly packed together * top down from the end of online memory. physmem_alloc_pos represents * current position where those allocations start. * * Functions randomize_within_range() and iterate_valid_positions() * only consider "dynamic" allocations by never looking above * physmem_alloc_pos. "Static" allocations, however, are explicitly * considered by checking the "res" (reserves) array. The first * reserved_range of a "dynamic" allocation may also be checked along the * way, but it will always be above the maximum value anyway. */ unsigned long randomize_within_range(unsigned long size, unsigned long align, unsigned long min, unsigned long max) { struct reserved_range res[RR_MAX]; unsigned long max_pos, pos; memcpy(res, physmem_info.reserved, sizeof(res)); sort_reserved_ranges(res, ARRAY_SIZE(res)); max = min(max, get_physmem_alloc_pos()); max_pos = iterate_valid_positions(size, align, min, max, res, ARRAY_SIZE(res), true, 0); if (!max_pos) return 0; if (get_random(max_pos, &pos)) return 0; return iterate_valid_positions(size, align, min, max, res, ARRAY_SIZE(res), false, pos + 1); } |