arch/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         if (image->type == KEXEC_TYPE_CRASH)
 191                 buf.mem += crashk_res.start;
 192
 193         ptr = (void *)ipl_cert_list_addr;
 194         end = ptr + ipl_cert_list_size;
 195         ncerts = 0;
 196         while (ptr < end) {
 197                 ncerts++;
 198                 len = *(unsigned int *)ptr;
 199                 ptr += sizeof(len);
 200                 ptr += len;
 201         }
 202
 203         addr = data->memsz + data->report->size;
 204         addr += ncerts * sizeof(struct ipl_rb_certificate_entry);
 205         ptr = (void *)ipl_cert_list_addr;
 206         while (ptr < end) {
 207                 len = *(unsigned int *)ptr;
 208                 ptr += sizeof(len);
 209                 ipl_report_add_certificate(data->report, ptr, addr, len);
 210                 addr += len;
 211                 ptr += len;
 212         }
 213
 214         ret = -ENOMEM;
 215         buf.buffer = ipl_report_finish(data->report);
 216         if (!buf.buffer)
 217                 goto out;
 218         buf.bufsz = data->report->size;
 219         buf.memsz = buf.bufsz;
 220         image->arch.ipl_buf = buf.buffer;
 221
 222         data->memsz += buf.memsz;
 223
 224         lc_ipl_parmblock_ptr =
 225                 data->kernel_buf + offsetof(struct lowcore, ipl_parmblock_ptr);
 226         *lc_ipl_parmblock_ptr = (__u32)buf.mem;
 227
 228         ret = kexec_add_buffer(&buf);
 229 out:
 230         return ret;
 231 }
 232
 233 void *kexec_file_add_components(struct kimage *image,
 234                                 int (*add_kernel)(struct kimage *image,
 235                                                   struct s390_load_data *data))
 236 {
 237         unsigned long max_command_line_size = LEGACY_COMMAND_LINE_SIZE;
 238         struct s390_load_data data = {0};
 239         unsigned long minsize;
 240         int ret;
 241
 242         data.report = ipl_report_init(&ipl_block);
 243         if (IS_ERR(data.report))
 244                 return data.report;
 245
 246         ret = add_kernel(image, &data);
 247         if (ret)
 248                 goto out;
 249
 250         ret = -EINVAL;
 251         minsize = PARMAREA + offsetof(struct parmarea, command_line);
 252         if (image->kernel_buf_len < minsize)
 253                 goto out;
 254
 255         if (data.parm->max_command_line_size)
 256                 max_command_line_size = data.parm->max_command_line_size;
 257
 258         if (minsize + max_command_line_size < minsize)
 259                 goto out;
 260
 261         if (image->kernel_buf_len < minsize + max_command_line_size)
 262                 goto out;
 263
 264         if (image->cmdline_buf_len >= max_command_line_size)
 265                 goto out;
 266
 267         memcpy(data.parm->command_line, image->cmdline_buf,
 268                image->cmdline_buf_len);
 269
 270         if (image->type == KEXEC_TYPE_CRASH) {
 271                 data.parm->oldmem_base = crashk_res.start;
 272                 data.parm->oldmem_size = crashk_res.end - crashk_res.start + 1;
 273         }
 274
 275         if (image->initrd_buf) {
 276                 ret = kexec_file_add_initrd(image, &data);
 277                 if (ret)
 278                         goto out;
 279         }
 280
 281         ret = kexec_file_add_purgatory(image, &data);
 282         if (ret)
 283                 goto out;
 284
 285         if (data.kernel_mem == 0) {
 286                 unsigned long restart_psw =  0x0008000080000000UL;
 287                 restart_psw += image->start;
 288                 memcpy(data.kernel_buf, &restart_psw, sizeof(restart_psw));
 289                 image->start = 0;
 290         }
 291
 292         ret = kexec_file_add_ipl_report(image, &data);
 293 out:
 294         ipl_report_free(data.report);
 295         return ERR_PTR(ret);
 296 }
 297
 298 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 299                                      Elf_Shdr *section,
 300                                      const Elf_Shdr *relsec,
 301                                      const Elf_Shdr *symtab)
 302 {
 303         const char *strtab, *name, *shstrtab;
 304         const Elf_Shdr *sechdrs;
 305         Elf_Rela *relas;
 306         int i, r_type;
 307         int ret;
 308
 309         /* String & section header string table */
 310         sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 311         strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset;
 312         shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
 313
 314         relas = (void *)pi->ehdr + relsec->sh_offset;
 315
 316         for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
 317                 const Elf_Sym *sym;     /* symbol to relocate */
 318                 unsigned long addr;     /* final location after relocation */
 319                 unsigned long val;      /* relocated symbol value */
 320                 void *loc;              /* tmp location to modify */
 321
 322                 sym = (void *)pi->ehdr + symtab->sh_offset;
 323                 sym += ELF64_R_SYM(relas[i].r_info);
 324
 325                 if (sym->st_name)
 326                         name = strtab + sym->st_name;
 327                 else
 328                         name = shstrtab + sechdrs[sym->st_shndx].sh_name;
 329
 330                 if (sym->st_shndx == SHN_UNDEF) {
 331                         pr_err("Undefined symbol: %s\n", name);
 332                         return -ENOEXEC;
 333                 }
 334
 335                 if (sym->st_shndx == SHN_COMMON) {
 336                         pr_err("symbol '%s' in common section\n", name);
 337                         return -ENOEXEC;
 338                 }
 339
 340                 if (sym->st_shndx >= pi->ehdr->e_shnum &&
 341                     sym->st_shndx != SHN_ABS) {
 342                         pr_err("Invalid section %d for symbol %s\n",
 343                                sym->st_shndx, name);
 344                         return -ENOEXEC;
 345                 }
 346
 347                 loc = pi->purgatory_buf;
 348                 loc += section->sh_offset;
 349                 loc += relas[i].r_offset;
 350
 351                 val = sym->st_value;
 352                 if (sym->st_shndx != SHN_ABS)
 353                         val += pi->sechdrs[sym->st_shndx].sh_addr;
 354                 val += relas[i].r_addend;
 355
 356                 addr = section->sh_addr + relas[i].r_offset;
 357
 358                 r_type = ELF64_R_TYPE(relas[i].r_info);
 359
 360                 if (r_type == R_390_PLT32DBL)
 361                         r_type = R_390_PC32DBL;
 362
 363                 ret = arch_kexec_do_relocs(r_type, loc, val, addr);
 364                 if (ret) {
 365                         pr_err("Unknown rela relocation: %d\n", r_type);
 366                         return -ENOEXEC;
 367                 }
 368         }
 369         return 0;
 370 }
 371
 372 int arch_kimage_file_post_load_cleanup(struct kimage *image)
 373 {
 374         vfree(image->arch.ipl_buf);
 375         image->arch.ipl_buf = NULL;
 376
 377         return kexec_image_post_load_cleanup_default(image);
 378 }