aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/kexec_elf.c
blob: 9da6fa30c44749fd7f4b044f5d211f7cd25d2b33 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
// SPDX-License-Identifier: GPL-2.0
/*
 * ELF loader for kexec_file_load system call.
 *
 * Copyright IBM Corp. 2018
 *
 * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <asm/ipl.h>
#include <asm/setup.h>

static int kexec_file_add_kernel_elf(struct kimage *image,
				     struct s390_load_data *data)
{
	struct kexec_buf buf;
	const Elf_Ehdr *ehdr;
	const Elf_Phdr *phdr;
	Elf_Addr entry;
	void *kernel;
	int i, ret;

	kernel = image->kernel_buf;
	ehdr = (Elf_Ehdr *)kernel;
	buf.image = image;
	if (image->type == KEXEC_TYPE_CRASH)
		entry = STARTUP_KDUMP_OFFSET;
	else
		entry = ehdr->e_entry;

	phdr = (void *)ehdr + ehdr->e_phoff;
	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
		if (phdr->p_type != PT_LOAD)
			continue;

		buf.buffer = kernel + phdr->p_offset;
		buf.bufsz = phdr->p_filesz;

		buf.mem = ALIGN(phdr->p_paddr, phdr->p_align);
		if (image->type == KEXEC_TYPE_CRASH)
			buf.mem += crashk_res.start;
		buf.memsz = phdr->p_memsz;
		data->memsz = ALIGN(data->memsz, phdr->p_align) + buf.memsz;

		if (entry - phdr->p_paddr < phdr->p_memsz) {
			data->kernel_buf = buf.buffer;
			data->kernel_mem = buf.mem;
			data->parm = buf.buffer + PARMAREA;
		}

		ipl_report_add_component(data->report, &buf,
					 IPL_RB_COMPONENT_FLAG_SIGNED |
					 IPL_RB_COMPONENT_FLAG_VERIFIED,
					 IPL_RB_CERT_UNKNOWN);
		ret = kexec_add_buffer(&buf);
		if (ret)
			return ret;
	}

	return data->memsz ? 0 : -EINVAL;
}

static void *s390_elf_load(struct kimage *image,
			   char *kernel, unsigned long kernel_len,
			   char *initrd, unsigned long initrd_len,
			   char *cmdline, unsigned long cmdline_len)
{
	const Elf_Ehdr *ehdr;
	const Elf_Phdr *phdr;
	size_t size;
	int i;

	/* image->fobs->probe already checked for valid ELF magic number. */
	ehdr = (Elf_Ehdr *)kernel;

	if (ehdr->e_type != ET_EXEC ||
	    ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
	    !elf_check_arch(ehdr))
		return ERR_PTR(-EINVAL);

	if (!ehdr->e_phnum || ehdr->e_phentsize != sizeof(Elf_Phdr))
		return ERR_PTR(-EINVAL);

	size = ehdr->e_ehsize + ehdr->e_phoff;
	size += ehdr->e_phentsize * ehdr->e_phnum;
	if (size > kernel_len)
		return ERR_PTR(-EINVAL);

	phdr = (void *)ehdr + ehdr->e_phoff;
	size = ALIGN(size, phdr->p_align);
	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
		if (phdr->p_type == PT_INTERP)
			return ERR_PTR(-EINVAL);

		if (phdr->p_offset > kernel_len)
			return ERR_PTR(-EINVAL);

		size += ALIGN(phdr->p_filesz, phdr->p_align);
	}

	if (size > kernel_len)
		return ERR_PTR(-EINVAL);

	return kexec_file_add_components(image, kexec_file_add_kernel_elf);
}

static int s390_elf_probe(const char *buf, unsigned long len)
{
	const Elf_Ehdr *ehdr;

	if (len < sizeof(Elf_Ehdr))
		return -ENOEXEC;

	ehdr = (Elf_Ehdr *)buf;

	/* Only check the ELF magic number here and do proper validity check
	 * in the loader. Any check here that fails would send the erroneous
	 * ELF file to the image loader that does not care what it gets.
	 * (Most likely) causing behavior not intended by the user.
	 */
	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
		return -ENOEXEC;

	return 0;
}

const struct kexec_file_ops s390_kexec_elf_ops = {
	.probe = s390_elf_probe,
	.load = s390_elf_load,
#ifdef CONFIG_KEXEC_SIG
	.verify_sig = s390_verify_sig,
#endif /* CONFIG_KEXEC_SIG */
};