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-rw-r--r--arch/s390/kernel/kexec_elf.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/s390/kernel/kexec_elf.c b/arch/s390/kernel/kexec_elf.c
new file mode 100644
index 000000000..9da6fa30c
--- /dev/null
+++ b/arch/s390/kernel/kexec_elf.c
@@ -0,0 +1,136 @@
+// 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 */
+};