1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * ELF loader 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/errno.h> 11 #include <linux/kernel.h> 12 #include <linux/kexec.h> 13 #include <asm/ipl.h> 14 #include <asm/setup.h> 15 16 static int kexec_file_add_kernel_elf(struct kimage *image, 17 struct s390_load_data *data) 18 { 19 struct kexec_buf buf; 20 const Elf_Ehdr *ehdr; 21 const Elf_Phdr *phdr; 22 Elf_Addr entry; 23 void *kernel; 24 int i, ret; 25 26 kernel = image->kernel_buf; 27 ehdr = (Elf_Ehdr *)kernel; 28 buf.image = image; 29 if (image->type == KEXEC_TYPE_CRASH) 30 entry = STARTUP_KDUMP_OFFSET; 31 else 32 entry = ehdr->e_entry; 33 34 phdr = (void *)ehdr + ehdr->e_phoff; 35 for (i = 0; i < ehdr->e_phnum; i++, phdr++) { 36 if (phdr->p_type != PT_LOAD) 37 continue; 38 39 buf.buffer = kernel + phdr->p_offset; 40 buf.bufsz = phdr->p_filesz; 41 42 buf.mem = ALIGN(phdr->p_paddr, phdr->p_align); 43 if (image->type == KEXEC_TYPE_CRASH) 44 buf.mem += crashk_res.start; 45 buf.memsz = phdr->p_memsz; 46 data->memsz = ALIGN(data->memsz, phdr->p_align) + buf.memsz; 47 48 if (entry - phdr->p_paddr < phdr->p_memsz) { 49 data->kernel_buf = buf.buffer; 50 data->kernel_mem = buf.mem; 51 data->parm = buf.buffer + PARMAREA; 52 } 53 54 ipl_report_add_component(data->report, &buf, 55 IPL_RB_COMPONENT_FLAG_SIGNED | 56 IPL_RB_COMPONENT_FLAG_VERIFIED, 57 IPL_RB_CERT_UNKNOWN); 58 ret = kexec_add_buffer(&buf); 59 if (ret) 60 return ret; 61 } 62 63 return data->memsz ? 0 : -EINVAL; 64 } 65 66 static void *s390_elf_load(struct kimage *image, 67 char *kernel, unsigned long kernel_len, 68 char *initrd, unsigned long initrd_len, 69 char *cmdline, unsigned long cmdline_len) 70 { 71 const Elf_Ehdr *ehdr; 72 const Elf_Phdr *phdr; 73 size_t size; 74 int i; 75 76 /* image->fobs->probe already checked for valid ELF magic number. */ 77 ehdr = (Elf_Ehdr *)kernel; 78 79 if (ehdr->e_type != ET_EXEC || 80 ehdr->e_ident[EI_CLASS] != ELFCLASS64 || 81 !elf_check_arch(ehdr)) 82 return ERR_PTR(-EINVAL); 83 84 if (!ehdr->e_phnum || ehdr->e_phentsize != sizeof(Elf_Phdr)) 85 return ERR_PTR(-EINVAL); 86 87 size = ehdr->e_ehsize + ehdr->e_phoff; 88 size += ehdr->e_phentsize * ehdr->e_phnum; 89 if (size > kernel_len) 90 return ERR_PTR(-EINVAL); 91 92 phdr = (void *)ehdr + ehdr->e_phoff; 93 size = ALIGN(size, phdr->p_align); 94 for (i = 0; i < ehdr->e_phnum; i++, phdr++) { 95 if (phdr->p_type == PT_INTERP) 96 return ERR_PTR(-EINVAL); 97 98 if (phdr->p_offset > kernel_len) 99 return ERR_PTR(-EINVAL); 100 101 size += ALIGN(phdr->p_filesz, phdr->p_align); 102 } 103 104 if (size > kernel_len) 105 return ERR_PTR(-EINVAL); 106 107 return kexec_file_add_components(image, kexec_file_add_kernel_elf); 108 } 109 110 static int s390_elf_probe(const char *buf, unsigned long len) 111 { 112 const Elf_Ehdr *ehdr; 113 114 if (len < sizeof(Elf_Ehdr)) 115 return -ENOEXEC; 116 117 ehdr = (Elf_Ehdr *)buf; 118 119 /* Only check the ELF magic number here and do proper validity check 120 * in the loader. Any check here that fails would send the erroneous 121 * ELF file to the image loader that does not care what it gets. 122 * (Most likely) causing behavior not intended by the user. 123 */ 124 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) 125 return -ENOEXEC; 126 127 return 0; 128 } 129 130 const struct kexec_file_ops s390_kexec_elf_ops = { 131 .probe = s390_elf_probe, 132 .load = s390_elf_load, 133 #ifdef CONFIG_KEXEC_SIG 134 .verify_sig = s390_verify_sig, 135 #endif /* CONFIG_KEXEC_SIG */ 136 }; 137