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 #ifdef CONFIG_CRASH_DUMP 44 if (image->type == KEXEC_TYPE_CRASH) 45 buf.mem += crashk_res.start; 46 #endif 47 buf.memsz = phdr->p_memsz; 48 data->memsz = ALIGN(data->memsz, phdr->p_align) + buf.memsz; 49 50 if (entry - phdr->p_paddr < phdr->p_memsz) { 51 data->kernel_buf = buf.buffer; 52 data->kernel_mem = buf.mem; 53 data->parm = buf.buffer + PARMAREA; 54 } 55 56 ipl_report_add_component(data->report, &buf, 57 IPL_RB_COMPONENT_FLAG_SIGNED | 58 IPL_RB_COMPONENT_FLAG_VERIFIED, 59 IPL_RB_CERT_UNKNOWN); 60 ret = kexec_add_buffer(&buf); 61 if (ret) 62 return ret; 63 } 64 65 return data->memsz ? 0 : -EINVAL; 66 } 67 68 static void *s390_elf_load(struct kimage *image, 69 char *kernel, unsigned long kernel_len, 70 char *initrd, unsigned long initrd_len, 71 char *cmdline, unsigned long cmdline_len) 72 { 73 const Elf_Ehdr *ehdr; 74 const Elf_Phdr *phdr; 75 size_t size; 76 int i; 77 78 /* image->fobs->probe already checked for valid ELF magic number. */ 79 ehdr = (Elf_Ehdr *)kernel; 80 81 if (ehdr->e_type != ET_EXEC || 82 ehdr->e_ident[EI_CLASS] != ELFCLASS64 || 83 !elf_check_arch(ehdr)) 84 return ERR_PTR(-EINVAL); 85 86 if (!ehdr->e_phnum || ehdr->e_phentsize != sizeof(Elf_Phdr)) 87 return ERR_PTR(-EINVAL); 88 89 size = ehdr->e_ehsize + ehdr->e_phoff; 90 size += ehdr->e_phentsize * ehdr->e_phnum; 91 if (size > kernel_len) 92 return ERR_PTR(-EINVAL); 93 94 phdr = (void *)ehdr + ehdr->e_phoff; 95 size = ALIGN(size, phdr->p_align); 96 for (i = 0; i < ehdr->e_phnum; i++, phdr++) { 97 if (phdr->p_type == PT_INTERP) 98 return ERR_PTR(-EINVAL); 99 100 if (phdr->p_offset > kernel_len) 101 return ERR_PTR(-EINVAL); 102 103 size += ALIGN(phdr->p_filesz, phdr->p_align); 104 } 105 106 if (size > kernel_len) 107 return ERR_PTR(-EINVAL); 108 109 return kexec_file_add_components(image, kexec_file_add_kernel_elf); 110 } 111 112 static int s390_elf_probe(const char *buf, unsigned long len) 113 { 114 const Elf_Ehdr *ehdr; 115 116 if (len < sizeof(Elf_Ehdr)) 117 return -ENOEXEC; 118 119 ehdr = (Elf_Ehdr *)buf; 120 121 /* Only check the ELF magic number here and do proper validity check 122 * in the loader. Any check here that fails would send the erroneous 123 * ELF file to the image loader that does not care what it gets. 124 * (Most likely) causing behavior not intended by the user. 125 */ 126 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0) 127 return -ENOEXEC; 128 129 return 0; 130 } 131 132 const struct kexec_file_ops s390_kexec_elf_ops = { 133 .probe = s390_elf_probe, 134 .load = s390_elf_load, 135 #ifdef CONFIG_KEXEC_SIG 136 .verify_sig = s390_verify_sig, 137 #endif /* CONFIG_KEXEC_SIG */ 138 }; 139