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
kexec_file_add_kernel_elf(struct kimage * image,struct s390_load_data * data)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
s390_elf_load(struct kimage * image,char * kernel,unsigned long kernel_len,char * initrd,unsigned long initrd_len,char * cmdline,unsigned long cmdline_len)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
s390_elf_probe(const char * buf,unsigned long len)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
