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 #include <linux/elf.h>
  11 #include <linux/errno.h>
  12 #include <linux/kexec.h>
  13 #include <linux/module_signature.h>
  14 #include <linux/verification.h>
  15 #include <asm/boot_data.h>
  16 #include <asm/ipl.h>
  17 #include <asm/setup.h>
  18
  19 const struct kexec_file_ops * const kexec_file_loaders[] = {
  20         &s390_kexec_elf_ops,
  21         &s390_kexec_image_ops,
  22         NULL,
  23 };
  24
  25 #ifdef CONFIG_KEXEC_SIG
  26 int s390_verify_sig(const char *kernel, unsigned long kernel_len)
  27 {
  28         const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
  29         struct module_signature *ms;
  30         unsigned long sig_len;
  31
  32         /* Skip signature verification when not secure IPLed. */
  33         if (!ipl_secure_flag)
  34                 return 0;
  35
  36         if (marker_len > kernel_len)
  37                 return -EKEYREJECTED;
  38
  39         if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING,
  40                    marker_len))
  41                 return -EKEYREJECTED;
  42         kernel_len -= marker_len;
  43
  44         ms = (void *)kernel + kernel_len - sizeof(*ms);
  45         kernel_len -= sizeof(*ms);
  46
  47         sig_len = be32_to_cpu(ms->sig_len);
  48         if (sig_len >= kernel_len)
  49                 return -EKEYREJECTED;
  50         kernel_len -= sig_len;
  51
  52         if (ms->id_type != PKEY_ID_PKCS7)
  53                 return -EKEYREJECTED;
  54
  55         if (ms->algo != 0 ||
  56             ms->hash != 0 ||
  57             ms->signer_len != 0 ||
  58             ms->key_id_len != 0 ||
  59             ms->__pad[0] != 0 ||
  60             ms->__pad[1] != 0 ||
  61             ms->__pad[2] != 0) {
  62                 return -EBADMSG;
  63         }
  64
  65         return verify_pkcs7_signature(kernel, kernel_len,
  66                                       kernel + kernel_len, sig_len,
  67                                       VERIFY_USE_PLATFORM_KEYRING,
  68                                       VERIFYING_MODULE_SIGNATURE,
  69                                       NULL, NULL);
  70 }
  71 #endif /* CONFIG_KEXEC_SIG */
  72
  73 static int kexec_file_update_purgatory(struct kimage *image,
  74                                        struct s390_load_data *data)
  75 {
  76         u64 entry, type;
  77         int ret;
  78
  79         if (image->type == KEXEC_TYPE_CRASH) {
  80                 entry = STARTUP_KDUMP_OFFSET;
  81                 type = KEXEC_TYPE_CRASH;
  82         } else {
  83                 entry = STARTUP_NORMAL_OFFSET;
  84                 type = KEXEC_TYPE_DEFAULT;
  85         }
  86
  87         ret = kexec_purgatory_get_set_symbol(image, "kernel_entry", &entry,
  88                                              sizeof(entry), false);
  89         if (ret)
  90                 return ret;
  91
  92         ret = kexec_purgatory_get_set_symbol(image, "kernel_type", &type,
  93                                              sizeof(type), false);
  94         if (ret)
  95                 return ret;
  96
  97         if (image->type == KEXEC_TYPE_CRASH) {
  98                 u64 crash_size;
  99
 100                 ret = kexec_purgatory_get_set_symbol(image, "crash_start",
 101                                                      &crashk_res.start,
 102                                                      sizeof(crashk_res.start),
 103                                                      false);
 104                 if (ret)
 105                         return ret;
 106
 107                 crash_size = crashk_res.end - crashk_res.start + 1;
 108                 ret = kexec_purgatory_get_set_symbol(image, "crash_size",
 109                                                      &crash_size,
 110                                                      sizeof(crash_size),
 111                                                      false);
 112         }
 113         return ret;
 114 }
 115
 116 static int kexec_file_add_purgatory(struct kimage *image,
 117                                     struct s390_load_data *data)
 118 {
 119         struct kexec_buf buf;
 120         int ret;
 121
 122         buf.image = image;
 123
 124         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 125         buf.mem = data->memsz;
 126         if (image->type == KEXEC_TYPE_CRASH)
 127                 buf.mem += crashk_res.start;
 128
 129         ret = kexec_load_purgatory(image, &buf);
 130         if (ret)
 131                 return ret;
 132         data->memsz += buf.memsz;
 133
 134         return kexec_file_update_purgatory(image, data);
 135 }
 136
 137 static int kexec_file_add_initrd(struct kimage *image,
 138                                  struct s390_load_data *data)
 139 {
 140         struct kexec_buf buf;
 141         int ret;
 142
 143         buf.image = image;
 144
 145         buf.buffer = image->initrd_buf;
 146         buf.bufsz = image->initrd_buf_len;
 147
 148         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 149         buf.mem = data->memsz;
 150         if (image->type == KEXEC_TYPE_CRASH)
 151                 buf.mem += crashk_res.start;
 152         buf.memsz = buf.bufsz;
 153
 154         data->parm->initrd_start = data->memsz;
 155         data->parm->initrd_size = buf.memsz;
 156         data->memsz += buf.memsz;
 157
 158         ret = kexec_add_buffer(&buf);
 159         if (ret)
 160                 return ret;
 161
 162         return ipl_report_add_component(data->report, &buf, 0, 0);
 163 }
 164
 165 static int kexec_file_add_ipl_report(struct kimage *image,
 166                                      struct s390_load_data *data)
 167 {
 168         __u32 *lc_ipl_parmblock_ptr;
 169         unsigned int len, ncerts;
 170         struct kexec_buf buf;
 171         unsigned long addr;
 172         void *ptr, *end;
 173
 174         buf.image = image;
 175
 176         data->memsz = ALIGN(data->memsz, PAGE_SIZE);
 177         buf.mem = data->memsz;
 178         if (image->type == KEXEC_TYPE_CRASH)
 179                 buf.mem += crashk_res.start;
 180
 181         ptr = (void *)ipl_cert_list_addr;
 182         end = ptr + ipl_cert_list_size;
 183         ncerts = 0;
 184         while (ptr < end) {
 185                 ncerts++;
 186                 len = *(unsigned int *)ptr;
 187                 ptr += sizeof(len);
 188                 ptr += len;
 189         }
 190
 191         addr = data->memsz + data->report->size;
 192         addr += ncerts * sizeof(struct ipl_rb_certificate_entry);
 193         ptr = (void *)ipl_cert_list_addr;
 194         while (ptr < end) {
 195                 len = *(unsigned int *)ptr;
 196                 ptr += sizeof(len);
 197                 ipl_report_add_certificate(data->report, ptr, addr, len);
 198                 addr += len;
 199                 ptr += len;
 200         }
 201
 202         buf.buffer = ipl_report_finish(data->report);
 203         buf.bufsz = data->report->size;
 204         buf.memsz = buf.bufsz;
 205
 206         data->memsz += buf.memsz;
 207
 208         lc_ipl_parmblock_ptr =
 209                 data->kernel_buf + offsetof(struct lowcore, ipl_parmblock_ptr);
 210         *lc_ipl_parmblock_ptr = (__u32)buf.mem;
 211
 212         return kexec_add_buffer(&buf);
 213 }
 214
 215 void *kexec_file_add_components(struct kimage *image,
 216                                 int (*add_kernel)(struct kimage *image,
 217                                                   struct s390_load_data *data))
 218 {
 219         struct s390_load_data data = {0};
 220         int ret;
 221
 222         data.report = ipl_report_init(&ipl_block);
 223         if (IS_ERR(data.report))
 224                 return data.report;
 225
 226         ret = add_kernel(image, &data);
 227         if (ret)
 228                 goto out;
 229
 230         if (image->cmdline_buf_len >= ARCH_COMMAND_LINE_SIZE) {
 231                 ret = -EINVAL;
 232                 goto out;
 233         }
 234         memcpy(data.parm->command_line, image->cmdline_buf,
 235                image->cmdline_buf_len);
 236
 237         if (image->type == KEXEC_TYPE_CRASH) {
 238                 data.parm->oldmem_base = crashk_res.start;
 239                 data.parm->oldmem_size = crashk_res.end - crashk_res.start + 1;
 240         }
 241
 242         if (image->initrd_buf) {
 243                 ret = kexec_file_add_initrd(image, &data);
 244                 if (ret)
 245                         goto out;
 246         }
 247
 248         ret = kexec_file_add_purgatory(image, &data);
 249         if (ret)
 250                 goto out;
 251
 252         if (data.kernel_mem == 0) {
 253                 unsigned long restart_psw =  0x0008000080000000UL;
 254                 restart_psw += image->start;
 255                 memcpy(data.kernel_buf, &restart_psw, sizeof(restart_psw));
 256                 image->start = 0;
 257         }
 258
 259         ret = kexec_file_add_ipl_report(image, &data);
 260 out:
 261         ipl_report_free(data.report);
 262         return ERR_PTR(ret);
 263 }
 264
 265 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 266                                      Elf_Shdr *section,
 267                                      const Elf_Shdr *relsec,
 268                                      const Elf_Shdr *symtab)
 269 {
 270         Elf_Rela *relas;
 271         int i, r_type;
 272
 273         relas = (void *)pi->ehdr + relsec->sh_offset;
 274
 275         for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
 276                 const Elf_Sym *sym;     /* symbol to relocate */
 277                 unsigned long addr;     /* final location after relocation */
 278                 unsigned long val;      /* relocated symbol value */
 279                 void *loc;              /* tmp location to modify */
 280
 281                 sym = (void *)pi->ehdr + symtab->sh_offset;
 282                 sym += ELF64_R_SYM(relas[i].r_info);
 283
 284                 if (sym->st_shndx == SHN_UNDEF)
 285                         return -ENOEXEC;
 286
 287                 if (sym->st_shndx == SHN_COMMON)
 288                         return -ENOEXEC;
 289
 290                 if (sym->st_shndx >= pi->ehdr->e_shnum &&
 291                     sym->st_shndx != SHN_ABS)
 292                         return -ENOEXEC;
 293
 294                 loc = pi->purgatory_buf;
 295                 loc += section->sh_offset;
 296                 loc += relas[i].r_offset;
 297
 298                 val = sym->st_value;
 299                 if (sym->st_shndx != SHN_ABS)
 300                         val += pi->sechdrs[sym->st_shndx].sh_addr;
 301                 val += relas[i].r_addend;
 302
 303                 addr = section->sh_addr + relas[i].r_offset;
 304
 305                 r_type = ELF64_R_TYPE(relas[i].r_info);
 306                 arch_kexec_do_relocs(r_type, loc, val, addr);
 307         }
 308         return 0;
 309 }
 310
 311 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
 312                                   unsigned long buf_len)
 313 {
 314         /* A kernel must be at least large enough to contain head.S. During
 315          * load memory in head.S will be accessed, e.g. to register the next
 316          * command line. If the next kernel were smaller the current kernel
 317          * will panic at load.
 318          */
 319         if (buf_len < HEAD_END)
 320                 return -ENOEXEC;
 321
 322         return kexec_image_probe_default(image, buf, buf_len);
 323 }