s390/kernel/machine_kexec_file.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * s390 code for kexec_file_load system call
   4  *
   5  * Copyright IBM Corp. 2018
   6  *
   7  * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
   8  */
   9
  10 #define pr_fmt(fmt)     "kexec: " fmt
  11
  12 #include <linux/elf.h>
  13 #include <linux/errno.h>
  14 #include <linux/kexec.h>
  15 #include <linux/module_signature.h>
  16 #include <linux/verification.h>
  17 #include <linux/vmalloc.h>
  18 #include <asm/boot_data.h>
  19 #include <asm/ipl.h>
  20 #include <asm/setup.h>
  21
  22 const struct kexec_file_ops * const kexec_file_loaders[] = {
  23         &s390_kexec_elf_ops,
  24         &s390_kexec_image_ops,
  25         NULL,
  26 };
  27
  28 #ifdef CONFIG_KEXEC_SIG
  29 int s390_verify_sig(const char *kernel, unsigned long kernel_len)
  30 {
  31         const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
  32         struct module_signature *ms;
  33         unsigned long sig_len;
  34         int ret;
  35
  36         /* Skip signature verification when not secure IPLed. */
  37         if (!ipl_secure_flag)
  38                 return 0;
  39
  40         if (marker_len > kernel_len)
  41                 return -EKEYREJECTED;
  42
  43         if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING,
  44                    marker_len))
  45                 return -EKEYREJECTED;
  46         kernel_len -= marker_len;
  47
  48         ms = (void *)kernel + kernel_len - sizeof(*ms);
  49         kernel_len -= sizeof(*ms);
  50
  51         sig_len = be32_to_cpu(ms->sig_len);
  52         if (sig_len >= kernel_len)
  53                 return -EKEYREJECTED;
  54         kernel_len -= sig_len;
  55
  56         if (ms->id_type != PKEY_ID_PKCS7)
  57                 return -EKEYREJECTED;
  58
  59         if (ms->algo != 0 ||
  60             ms->hash != 0 ||
  61             ms->signer_len != 0 ||
  62             ms->key_id_len != 0 ||
  63             ms->__pad[0] != 0 ||
  64             ms->__pad[1] != 0 ||
  65             ms->__pad[2] != 0) {
  66                 return -EBADMSG;
  67         }
  68
  69         ret = verify_pkcs7_signature(kernel, kernel_len,
  70                                      kernel + kernel_len, sig_len,
  71                                      VERIFY_USE_SECONDARY_KEYRING,
  72                                      VERIFYING_MODULE_SIGNATURE,
  73                                      NULL, NULL);
  74         if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
  75                 ret = verify_pkcs7_signature(kernel, kernel_len,
  76                                              kernel + kernel_len, sig_len,
  77                                              VERIFY_USE_PLATFORM_KEYRING,
  78                                              VERIFYING_MODULE_SIGNATURE,
  79                                              NULL, NULL);
  80         return ret;
  81 }
  82 #endif /* CONFIG_KEXEC_SIG */
  83
  84 static int kexec_file_update_purgatory(struct kimage *image,
  85                                        struct s390_load_data *data)
  86 {
  87         u64 entry, type;
  88         int ret;
  89
  90         if (image->type == KEXEC_TYPE_CRASH) {
  91                 entry = STARTUP_KDUMP_OFFSET;
  92                 type = KEXEC_TYPE_CRASH;
  93         } else {
  94                 entry = STARTUP_NORMAL_OFFSET;
  95                 type = KEXEC_TYPE_DEFAULT;
  96         }
  97
  98         ret = kexec_purgatory_get_set_symbol(image, "kernel_entry", &entry,
  99                                              sizeof(entry), false);
 100         if (ret)
 101                 return ret;
 102
 103         ret = kexec_purgatory_get_set_symbol(image, "kernel_type", &type,
 104                                              sizeof(type), false);
 105         if (ret)
 106                 return ret;
 107
 108         if (image->type == KEXEC_TYPE_CRASH) {
 109                 u64 crash_size;
 110
 111                 ret = kexec_purgatory_get_set_symbol(image, "crash_start",
 112                                                      &crashk_res.start,
 113                                                      sizeof(crashk_res.start),
 114                                                      false);
 115                 if (ret)
 116                         return ret;
 117
 118                 crash_size = crashk_res.end - crashk_res.start + 1;
 119                 ret = kexec_purgatory_get_set_symbol(image, "crash_size",
 120                                                      &crash_size,
 121                                                      sizeof(crash_size),
 122                                                      false);
 123         }
 124         return ret;
 125 }
 126
 127 static int kexec_file_add_purgatory(struct kimage *image,
 128                                     struct s390_load_data *data)
 129 {
 130         struct kexec_buf buf;
 131         int ret;
 132
 133         buf.image = image;
 134
 135         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 136         buf.mem = data->memsz;
 137         if (image->type == KEXEC_TYPE_CRASH)
 138                 buf.mem += crashk_res.start;
 139
 140         ret = kexec_load_purgatory(image, &buf);
 141         if (ret)
 142                 return ret;
 143         data->memsz += buf.memsz;
 144
 145         return kexec_file_update_purgatory(image, data);
 146 }
 147
 148 static int kexec_file_add_initrd(struct kimage *image,
 149                                  struct s390_load_data *data)
 150 {
 151         struct kexec_buf buf;
 152         int ret;
 153
 154         buf.image = image;
 155
 156         buf.buffer = image->initrd_buf;
 157         buf.bufsz = image->initrd_buf_len;
 158
 159         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 160         buf.mem = data->memsz;
 161         if (image->type == KEXEC_TYPE_CRASH)
 162                 buf.mem += crashk_res.start;
 163         buf.memsz = buf.bufsz;
 164
 165         data->parm->initrd_start = data->memsz;
 166         data->parm->initrd_size = buf.memsz;
 167         data->memsz += buf.memsz;
 168
 169         ret = kexec_add_buffer(&buf);
 170         if (ret)
 171                 return ret;
 172
 173         return ipl_report_add_component(data->report, &buf, 0, 0);
 174 }
 175
 176 static int kexec_file_add_ipl_report(struct kimage *image,
 177                                      struct s390_load_data *data)
 178 {
 179         __u32 *lc_ipl_parmblock_ptr;
 180         unsigned int len, ncerts;
 181         struct kexec_buf buf;
 182         unsigned long addr;
 183         void *ptr, *end;
 184         int ret;
 185
 186         buf.image = image;
 187
 188         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 189         buf.mem = data->memsz;
 190
 191         ptr = (void *)ipl_cert_list_addr;
 192         end = ptr + ipl_cert_list_size;
 193         ncerts = 0;
 194         while (ptr < end) {
 195                 ncerts++;
 196                 len = *(unsigned int *)ptr;
 197                 ptr += sizeof(len);
 198                 ptr += len;
 199         }
 200
 201         addr = data->memsz + data->report->size;
 202         addr += ncerts * sizeof(struct ipl_rb_certificate_entry);
 203         ptr = (void *)ipl_cert_list_addr;
 204         while (ptr < end) {
 205                 len = *(unsigned int *)ptr;
 206                 ptr += sizeof(len);
 207                 ipl_report_add_certificate(data->report, ptr, addr, len);
 208                 addr += len;
 209                 ptr += len;
 210         }
 211
 212         ret = -ENOMEM;
 213         buf.buffer = ipl_report_finish(data->report);
 214         if (!buf.buffer)
 215                 goto out;
 216         buf.bufsz = data->report->size;
 217         buf.memsz = buf.bufsz;
 218         image->arch.ipl_buf = buf.buffer;
 219
 220         data->memsz += buf.memsz;
 221
 222         lc_ipl_parmblock_ptr =
 223                 data->kernel_buf + offsetof(struct lowcore, ipl_parmblock_ptr);
 224         *lc_ipl_parmblock_ptr = (__u32)buf.mem;
 225
 226         if (image->type == KEXEC_TYPE_CRASH)
 227                 buf.mem += crashk_res.start;
 228
 229         ret = kexec_add_buffer(&buf);
 230 out:
 231         return ret;
 232 }
 233
 234 void *kexec_file_add_components(struct kimage *image,
 235                                 int (*add_kernel)(struct kimage *image,
 236                                                   struct s390_load_data *data))
 237 {
 238         unsigned long max_command_line_size = LEGACY_COMMAND_LINE_SIZE;
 239         struct s390_load_data data = {0};
 240         unsigned long minsize;
 241         int ret;
 242
 243         data.report = ipl_report_init(&ipl_block);
 244         if (IS_ERR(data.report))
 245                 return data.report;
 246
 247         ret = add_kernel(image, &data);
 248         if (ret)
 249                 goto out;
 250
 251         ret = -EINVAL;
 252         minsize = PARMAREA + offsetof(struct parmarea, command_line);
 253         if (image->kernel_buf_len < minsize)
 254                 goto out;
 255
 256         if (data.parm->max_command_line_size)
 257                 max_command_line_size = data.parm->max_command_line_size;
 258
 259         if (minsize + max_command_line_size < minsize)
 260                 goto out;
 261
 262         if (image->kernel_buf_len < minsize + max_command_line_size)
 263                 goto out;
 264
 265         if (image->cmdline_buf_len >= max_command_line_size)
 266                 goto out;
 267
 268         memcpy(data.parm->command_line, image->cmdline_buf,
 269                image->cmdline_buf_len);
 270
 271         if (image->type == KEXEC_TYPE_CRASH) {
 272                 data.parm->oldmem_base = crashk_res.start;
 273                 data.parm->oldmem_size = crashk_res.end - crashk_res.start + 1;
 274         }
 275
 276         if (image->initrd_buf) {
 277                 ret = kexec_file_add_initrd(image, &data);
 278                 if (ret)
 279                         goto out;
 280         }
 281
 282         ret = kexec_file_add_purgatory(image, &data);
 283         if (ret)
 284                 goto out;
 285
 286         if (data.kernel_mem == 0) {
 287                 unsigned long restart_psw =  0x0008000080000000UL;
 288                 restart_psw += image->start;
 289                 memcpy(data.kernel_buf, &restart_psw, sizeof(restart_psw));
 290                 image->start = 0;
 291         }
 292
 293         ret = kexec_file_add_ipl_report(image, &data);
 294 out:
 295         ipl_report_free(data.report);
 296         return ERR_PTR(ret);
 297 }
 298
 299 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 300                                      Elf_Shdr *section,
 301                                      const Elf_Shdr *relsec,
 302                                      const Elf_Shdr *symtab)
 303 {
 304         const char *strtab, *name, *shstrtab;
 305         const Elf_Shdr *sechdrs;
 306         Elf_Rela *relas;
 307         int i, r_type;
 308         int ret;
 309
 310         /* String & section header string table */
 311         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 312         strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset;
 313         shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
 314
 315         relas = (void *)pi->ehdr + relsec->sh_offset;
 316
 317         for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
 318                 const Elf_Sym *sym;     /* symbol to relocate */
 319                 unsigned long addr;     /* final location after relocation */
 320                 unsigned long val;      /* relocated symbol value */
 321                 void *loc;              /* tmp location to modify */
 322
 323                 sym = (void *)pi->ehdr + symtab->sh_offset;
 324                 sym += ELF64_R_SYM(relas[i].r_info);
 325
 326                 if (sym->st_name)
 327                         name = strtab + sym->st_name;
 328                 else
 329                         name = shstrtab + sechdrs[sym->st_shndx].sh_name;
 330
 331                 if (sym->st_shndx == SHN_UNDEF) {
 332                         pr_err("Undefined symbol: %s\n", name);
 333                         return -ENOEXEC;
 334                 }
 335
 336                 if (sym->st_shndx == SHN_COMMON) {
 337                         pr_err("symbol '%s' in common section\n", name);
 338                         return -ENOEXEC;
 339                 }
 340
 341                 if (sym->st_shndx >= pi->ehdr->e_shnum &&
 342                     sym->st_shndx != SHN_ABS) {
 343                         pr_err("Invalid section %d for symbol %s\n",
 344                                sym->st_shndx, name);
 345                         return -ENOEXEC;
 346                 }
 347
 348                 loc = pi->purgatory_buf;
 349                 loc += section->sh_offset;
 350                 loc += relas[i].r_offset;
 351
 352                 val = sym->st_value;
 353                 if (sym->st_shndx != SHN_ABS)
 354                         val += pi->sechdrs[sym->st_shndx].sh_addr;
 355                 val += relas[i].r_addend;
 356
 357                 addr = section->sh_addr + relas[i].r_offset;
 358
 359                 r_type = ELF64_R_TYPE(relas[i].r_info);
 360
 361                 if (r_type == R_390_PLT32DBL)
 362                         r_type = R_390_PC32DBL;
 363
 364                 ret = arch_kexec_do_relocs(r_type, loc, val, addr);
 365                 if (ret) {
 366                         pr_err("Unknown rela relocation: %d\n", r_type);
 367                         return -ENOEXEC;
 368                 }
 369         }
 370         return 0;
 371 }
 372
 373 int arch_kimage_file_post_load_cleanup(struct kimage *image)
 374 {
 375         vfree(image->arch.ipl_buf);
 376         image->arch.ipl_buf = NULL;
 377
 378         return kexec_image_post_load_cleanup_default(image);
 379 }