[PATCHv3 2/3] kexec: Introduce UKI image parser
Pingfan Liu
piliu at redhat.com
Mon Oct 21 23:27:18 PDT 2024
A UKI image is a PE file that consists of several sections, typically
including: .text, .data, .linux, .initrd, .cmdline, and others.
The kernel image is stored in the .linux section, which is one of the
formats currently recognized by kexec-tools. Therefore, the UKI parser
can be used to strip away the UKI layer, allowing the other parser to
continue the procession of the kernel image.
Signed-off-by: Pingfan Liu <piliu at redhat.com>
Cc: Simon Horman <horms at kernel.org>
Cc: kexec at lists.infradead.org
---
include/Makefile | 1 +
include/pe.h | 104 +++++++++++++++++++++++++++++++++++++++
kexec/Makefile | 1 +
kexec/kexec-uki.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++
kexec/kexec.h | 4 ++
5 files changed, 233 insertions(+)
create mode 100644 include/pe.h
create mode 100644 kexec/kexec-uki.c
diff --git a/include/Makefile b/include/Makefile
index cd88a26..6a3e854 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -8,6 +8,7 @@ dist += include/Makefile \
include/x86/mb_header.h \
include/x86/multiboot2.h \
include/elf.h \
+ include/pe.h \
include/image.h \
include/unused.h \
include/boot/linuxbios_tables.h \
diff --git a/include/pe.h b/include/pe.h
new file mode 100644
index 0000000..2617074
--- /dev/null
+++ b/include/pe.h
@@ -0,0 +1,104 @@
+/*
+ * Extract from linux kernel include/linux/pe.h
+ */
+
+#ifndef __PE_H__
+#define __PE_H__
+
+struct pe_hdr {
+ uint32_t magic; /* PE magic */
+ uint16_t machine; /* machine type */
+ uint16_t sections; /* number of sections */
+ uint32_t timestamp; /* time_t */
+ uint32_t symbol_table; /* symbol table offset */
+ uint32_t symbols; /* number of symbols */
+ uint16_t opt_hdr_size; /* size of optional header */
+ uint16_t flags; /* flags */
+};
+
+/* the fact that pe32 isn't padded where pe32+ is 64-bit means union won't
+ * work right. vomit. */
+struct pe32_opt_hdr {
+ /* "standard" header */
+ uint16_t magic; /* file type */
+ uint8_t ld_major; /* linker major version */
+ uint8_t ld_minor; /* linker minor version */
+ uint32_t text_size; /* size of text section(s) */
+ uint32_t data_size; /* size of data section(s) */
+ uint32_t bss_size; /* size of bss section(s) */
+ uint32_t entry_point; /* file offset of entry point */
+ uint32_t code_base; /* relative code addr in ram */
+ uint32_t data_base; /* relative data addr in ram */
+ /* "windows" header */
+ uint32_t image_base; /* preferred load address */
+ uint32_t section_align; /* alignment in bytes */
+ uint32_t file_align; /* file alignment in bytes */
+ uint16_t os_major; /* major OS version */
+ uint16_t os_minor; /* minor OS version */
+ uint16_t image_major; /* major image version */
+ uint16_t image_minor; /* minor image version */
+ uint16_t subsys_major; /* major subsystem version */
+ uint16_t subsys_minor; /* minor subsystem version */
+ uint32_t win32_version; /* reserved, must be 0 */
+ uint32_t image_size; /* image size */
+ uint32_t header_size; /* header size rounded up to
+ file_align */
+ uint32_t csum; /* checksum */
+ uint16_t subsys; /* subsystem */
+ uint16_t dll_flags; /* more flags! */
+ uint32_t stack_size_req;/* amt of stack requested */
+ uint32_t stack_size; /* amt of stack required */
+ uint32_t heap_size_req; /* amt of heap requested */
+ uint32_t heap_size; /* amt of heap required */
+ uint32_t loader_flags; /* reserved, must be 0 */
+ uint32_t data_dirs; /* number of data dir entries */
+};
+
+struct pe32plus_opt_hdr {
+ uint16_t magic; /* file type */
+ uint8_t ld_major; /* linker major version */
+ uint8_t ld_minor; /* linker minor version */
+ uint32_t text_size; /* size of text section(s) */
+ uint32_t data_size; /* size of data section(s) */
+ uint32_t bss_size; /* size of bss section(s) */
+ uint32_t entry_point; /* file offset of entry point */
+ uint32_t code_base; /* relative code addr in ram */
+ /* "windows" header */
+ uint64_t image_base; /* preferred load address */
+ uint32_t section_align; /* alignment in bytes */
+ uint32_t file_align; /* file alignment in bytes */
+ uint16_t os_major; /* major OS version */
+ uint16_t os_minor; /* minor OS version */
+ uint16_t image_major; /* major image version */
+ uint16_t image_minor; /* minor image version */
+ uint16_t subsys_major; /* major subsystem version */
+ uint16_t subsys_minor; /* minor subsystem version */
+ uint32_t win32_version; /* reserved, must be 0 */
+ uint32_t image_size; /* image size */
+ uint32_t header_size; /* header size rounded up to
+ file_align */
+ uint32_t csum; /* checksum */
+ uint16_t subsys; /* subsystem */
+ uint16_t dll_flags; /* more flags! */
+ uint64_t stack_size_req;/* amt of stack requested */
+ uint64_t stack_size; /* amt of stack required */
+ uint64_t heap_size_req; /* amt of heap requested */
+ uint64_t heap_size; /* amt of heap required */
+ uint32_t loader_flags; /* reserved, must be 0 */
+ uint32_t data_dirs; /* number of data dir entries */
+};
+
+struct section_header {
+ char name[8]; /* name or "/12\0" string tbl offset */
+ uint32_t virtual_size; /* size of loaded section in ram */
+ uint32_t virtual_address; /* relative virtual address */
+ uint32_t raw_data_size; /* size of the section */
+ uint32_t data_addr; /* file pointer to first page of sec */
+ uint32_t relocs; /* file pointer to relocation entries */
+ uint32_t line_numbers; /* line numbers! */
+ uint16_t num_relocs; /* number of relocations */
+ uint16_t num_lin_numbers; /* srsly. */
+ uint32_t flags;
+};
+
+#endif
diff --git a/kexec/Makefile b/kexec/Makefile
index 11682bf..d4f26d7 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -18,6 +18,7 @@ KEXEC_SRCS_base += kexec/kexec-elf-core.c
KEXEC_SRCS_base += kexec/kexec-elf-rel.c
KEXEC_SRCS_base += kexec/kexec-elf-boot.c
KEXEC_SRCS_base += kexec/kexec-pe-zboot.c
+KEXEC_SRCS_base += kexec/kexec-uki.c
KEXEC_SRCS_base += kexec/kexec-iomem.c
KEXEC_SRCS_base += kexec/firmware_memmap.c
KEXEC_SRCS_base += kexec/crashdump.c
diff --git a/kexec/kexec-uki.c b/kexec/kexec-uki.c
new file mode 100644
index 0000000..210ebb6
--- /dev/null
+++ b/kexec/kexec-uki.c
@@ -0,0 +1,123 @@
+#include <limits.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <pe.h>
+#include "kexec.h"
+
+#define UKI_LINUX_SECTION ".linux"
+#define UKI_INITRD_SECTION ".initrd"
+#define UKI_CMDLINE_SECTION ".cmdline"
+#define UKI_DTB_SECTION ".dtb"
+
+#define FILENAME_UKI_INITRD "/tmp/InitrdXXXXXX"
+
+static int embeded_linux_format_index = -1;
+
+/*
+ * Return -1 if not PE, else offset of the PE header
+ */
+static int get_pehdr_offset(const char *buf)
+{
+ int pe_hdr_offset;
+
+ pe_hdr_offset = *((int *)(buf + 0x3c));
+ buf += pe_hdr_offset;
+ if (!!memcmp(buf, "PE\0\0", 4)) {
+ printf("Not a PE file\n");
+ return -1;
+ }
+
+ return pe_hdr_offset;
+}
+
+int uki_image_probe(const char *file_buf, off_t buf_sz)
+{
+ struct pe_hdr *pe_hdr;
+ struct pe32plus_opt_hdr *opt_hdr;
+ struct section_header *sect_hdr;
+ int pe_hdr_offset, section_nr, linux_sz = -1;
+ char *pe_part_buf, *linux_src;
+ char *initrd_fname = NULL;
+ int initrd_fd = -1;
+
+ pe_hdr_offset = get_pehdr_offset(file_buf);
+ pe_part_buf = (char *)file_buf + pe_hdr_offset;
+ pe_hdr = (struct pe_hdr *)pe_part_buf;
+ if (pe_hdr->opt_hdr_size == 0) {
+ printf("ERR: optional header is missing\n");
+ return -1;
+ }
+ section_nr = pe_hdr->sections;
+ opt_hdr = (struct pe32plus_opt_hdr *)(pe_part_buf + sizeof(struct pe_hdr));
+ sect_hdr = (struct section_header *)((char *)opt_hdr + pe_hdr->opt_hdr_size);
+
+ for (int i = 0; i < section_nr; i++) {
+ if (!strcmp(sect_hdr->name, UKI_LINUX_SECTION)) {
+ /* data_addr is relative to the whole file */
+ linux_src = (char *)file_buf + sect_hdr->data_addr;
+ linux_sz = sect_hdr->raw_data_size;
+
+ } else if (!strcmp(sect_hdr->name, UKI_INITRD_SECTION)) {
+ if (!(initrd_fname = strdup(FILENAME_UKI_INITRD))) {
+ dbgprintf("%s: Can't duplicate strings\n", __func__);
+ goto next;
+ }
+
+ if ((initrd_fd = mkstemp(initrd_fname)) < 0) {
+ dbgprintf("%s: Can't open file %s\n", __func__, initrd_fname);
+ goto next;
+ }
+
+ if (write(initrd_fd, (char *)file_buf + sect_hdr->data_addr,
+ sect_hdr->raw_data_size) != sect_hdr->raw_data_size) {
+ dbgprintf("%s: Can't write the compressed file %s\n",
+ __func__, initrd_fname);
+ close(initrd_fd);
+ goto next;
+ } else {
+ implicit_initrd_fd = open(initrd_fname, O_RDONLY);
+ close(initrd_fd);
+ }
+ }
+next:
+ sect_hdr++;
+ }
+
+ if (linux_sz == -1) {
+ printf("ERR: can not find .linux section\n");
+ return -1;
+ }
+ /*
+ * After stripping the UKI coat, the real kernel format can be handled now.
+ */
+ for (int i = 0; i < file_types; i++) {
+ /* kernel_fd will be created by probe */
+ if (file_type[i].probe != uki_image_probe &&
+ file_type[i].probe(linux_src, linux_sz) >= 0) {
+ embeded_linux_format_index = i;
+ break;
+ }
+ }
+ if (embeded_linux_format_index < 0) {
+ printf("Can not recognize the kernel format in .linux section\n");
+ return -1;
+ }
+ return 0;
+}
+
+int uki_image_load(int argc, char **argv, const char *buf, off_t len,
+ struct kexec_info *info)
+{
+ return file_type[embeded_linux_format_index].load(argc, argv, buf, len, info);
+}
+
+void uki_image_usage(void)
+{
+ printf(
+" An UKI image.\n");
+}
diff --git a/kexec/kexec.h b/kexec/kexec.h
index e70c18d..a2e19c4 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -357,4 +357,8 @@ static inline void ultoa(unsigned long val, char *str)
str[pos] = 0;
}
+extern int uki_image_probe(const char *file_buf, off_t buf_sz);
+extern int uki_image_load(int argc, char **argv, const char *buf, off_t len,
+ struct kexec_info *info);
+extern void uki_image_usage(void);
#endif /* KEXEC_H */
--
2.41.0
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