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(kbuf: &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(error: -EINVAL); |
85 | |
86 | if (!ehdr->e_phnum || ehdr->e_phentsize != sizeof(Elf_Phdr)) |
87 | return ERR_PTR(error: -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(error: -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(error: -EINVAL); |
99 | |
100 | if (phdr->p_offset > kernel_len) |
101 | return ERR_PTR(error: -EINVAL); |
102 | |
103 | size += ALIGN(phdr->p_filesz, phdr->p_align); |
104 | } |
105 | |
106 | if (size > kernel_len) |
107 | return ERR_PTR(error: -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(p: 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 | |