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 0000000000..9da6fa30c4
--- /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 */
+};