mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
411 lines
8.9 KiB
C
411 lines
8.9 KiB
C
![]() |
/* Write the contents of the <certfile> into kernel symbol system_extra_cert
|
||
|
*
|
||
|
* Copyright (C) IBM Corporation, 2015
|
||
|
*
|
||
|
* Author: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
|
||
|
*
|
||
|
* This software may be used and distributed according to the terms
|
||
|
* of the GNU General Public License, incorporated herein by reference.
|
||
|
*
|
||
|
* Usage: insert-sys-cert [-s <System.map> -b <vmlinux> -c <certfile>
|
||
|
*/
|
||
|
|
||
|
#define _GNU_SOURCE
|
||
|
#include <stdio.h>
|
||
|
#include <ctype.h>
|
||
|
#include <string.h>
|
||
|
#include <limits.h>
|
||
|
#include <stdbool.h>
|
||
|
#include <errno.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <stdarg.h>
|
||
|
#include <sys/types.h>
|
||
|
#include <sys/stat.h>
|
||
|
#include <sys/mman.h>
|
||
|
#include <fcntl.h>
|
||
|
#include <unistd.h>
|
||
|
#include <elf.h>
|
||
|
|
||
|
#define CERT_SYM "system_extra_cert"
|
||
|
#define USED_SYM "system_extra_cert_used"
|
||
|
#define LSIZE_SYM "system_certificate_list_size"
|
||
|
|
||
|
#define info(format, args...) fprintf(stderr, "INFO: " format, ## args)
|
||
|
#define warn(format, args...) fprintf(stdout, "WARNING: " format, ## args)
|
||
|
#define err(format, args...) fprintf(stderr, "ERROR: " format, ## args)
|
||
|
|
||
|
#if UINTPTR_MAX == 0xffffffff
|
||
|
#define CURRENT_ELFCLASS ELFCLASS32
|
||
|
#define Elf_Ehdr Elf32_Ehdr
|
||
|
#define Elf_Shdr Elf32_Shdr
|
||
|
#define Elf_Sym Elf32_Sym
|
||
|
#else
|
||
|
#define CURRENT_ELFCLASS ELFCLASS64
|
||
|
#define Elf_Ehdr Elf64_Ehdr
|
||
|
#define Elf_Shdr Elf64_Shdr
|
||
|
#define Elf_Sym Elf64_Sym
|
||
|
#endif
|
||
|
|
||
|
static unsigned char endianness(void)
|
||
|
{
|
||
|
uint16_t two_byte = 0x00FF;
|
||
|
uint8_t low_address = *((uint8_t *)&two_byte);
|
||
|
|
||
|
if (low_address == 0)
|
||
|
return ELFDATA2MSB;
|
||
|
else
|
||
|
return ELFDATA2LSB;
|
||
|
}
|
||
|
|
||
|
struct sym {
|
||
|
char *name;
|
||
|
unsigned long address;
|
||
|
unsigned long offset;
|
||
|
void *content;
|
||
|
int size;
|
||
|
};
|
||
|
|
||
|
static unsigned long get_offset_from_address(Elf_Ehdr *hdr, unsigned long addr)
|
||
|
{
|
||
|
Elf_Shdr *x;
|
||
|
unsigned int i, num_sections;
|
||
|
|
||
|
x = (void *)hdr + hdr->e_shoff;
|
||
|
if (hdr->e_shnum == SHN_UNDEF)
|
||
|
num_sections = x[0].sh_size;
|
||
|
else
|
||
|
num_sections = hdr->e_shnum;
|
||
|
|
||
|
for (i = 1; i < num_sections; i++) {
|
||
|
unsigned long start = x[i].sh_addr;
|
||
|
unsigned long end = start + x[i].sh_size;
|
||
|
unsigned long offset = x[i].sh_offset;
|
||
|
|
||
|
if (addr >= start && addr <= end)
|
||
|
return addr - start + offset;
|
||
|
}
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
|
||
|
#define LINE_SIZE 100
|
||
|
|
||
|
static void get_symbol_from_map(Elf_Ehdr *hdr, FILE *f, char *name,
|
||
|
struct sym *s)
|
||
|
{
|
||
|
char l[LINE_SIZE];
|
||
|
char *w, *p, *n;
|
||
|
|
||
|
s->size = 0;
|
||
|
s->address = 0;
|
||
|
s->offset = 0;
|
||
|
if (fseek(f, 0, SEEK_SET) != 0) {
|
||
|
perror("File seek failed");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
while (fgets(l, LINE_SIZE, f)) {
|
||
|
p = strchr(l, '\n');
|
||
|
if (!p) {
|
||
|
err("Missing line ending.\n");
|
||
|
return;
|
||
|
}
|
||
|
n = strstr(l, name);
|
||
|
if (n)
|
||
|
break;
|
||
|
}
|
||
|
if (!n) {
|
||
|
err("Unable to find symbol: %s\n", name);
|
||
|
return;
|
||
|
}
|
||
|
w = strchr(l, ' ');
|
||
|
if (!w)
|
||
|
return;
|
||
|
|
||
|
*w = '\0';
|
||
|
s->address = strtoul(l, NULL, 16);
|
||
|
if (s->address == 0)
|
||
|
return;
|
||
|
s->offset = get_offset_from_address(hdr, s->address);
|
||
|
s->name = name;
|
||
|
s->content = (void *)hdr + s->offset;
|
||
|
}
|
||
|
|
||
|
static Elf_Sym *find_elf_symbol(Elf_Ehdr *hdr, Elf_Shdr *symtab, char *name)
|
||
|
{
|
||
|
Elf_Sym *sym, *symtab_start;
|
||
|
char *strtab, *symname;
|
||
|
unsigned int link;
|
||
|
Elf_Shdr *x;
|
||
|
int i, n;
|
||
|
|
||
|
x = (void *)hdr + hdr->e_shoff;
|
||
|
link = symtab->sh_link;
|
||
|
symtab_start = (void *)hdr + symtab->sh_offset;
|
||
|
n = symtab->sh_size / symtab->sh_entsize;
|
||
|
strtab = (void *)hdr + x[link].sh_offset;
|
||
|
|
||
|
for (i = 0; i < n; i++) {
|
||
|
sym = &symtab_start[i];
|
||
|
symname = strtab + sym->st_name;
|
||
|
if (strcmp(symname, name) == 0)
|
||
|
return sym;
|
||
|
}
|
||
|
err("Unable to find symbol: %s\n", name);
|
||
|
return NULL;
|
||
|
}
|
||
|
|
||
|
static void get_symbol_from_table(Elf_Ehdr *hdr, Elf_Shdr *symtab,
|
||
|
char *name, struct sym *s)
|
||
|
{
|
||
|
Elf_Shdr *sec;
|
||
|
int secndx;
|
||
|
Elf_Sym *elf_sym;
|
||
|
Elf_Shdr *x;
|
||
|
|
||
|
x = (void *)hdr + hdr->e_shoff;
|
||
|
s->size = 0;
|
||
|
s->address = 0;
|
||
|
s->offset = 0;
|
||
|
elf_sym = find_elf_symbol(hdr, symtab, name);
|
||
|
if (!elf_sym)
|
||
|
return;
|
||
|
secndx = elf_sym->st_shndx;
|
||
|
if (!secndx)
|
||
|
return;
|
||
|
sec = &x[secndx];
|
||
|
s->size = elf_sym->st_size;
|
||
|
s->address = elf_sym->st_value;
|
||
|
s->offset = s->address - sec->sh_addr
|
||
|
+ sec->sh_offset;
|
||
|
s->name = name;
|
||
|
s->content = (void *)hdr + s->offset;
|
||
|
}
|
||
|
|
||
|
static Elf_Shdr *get_symbol_table(Elf_Ehdr *hdr)
|
||
|
{
|
||
|
Elf_Shdr *x;
|
||
|
unsigned int i, num_sections;
|
||
|
|
||
|
x = (void *)hdr + hdr->e_shoff;
|
||
|
if (hdr->e_shnum == SHN_UNDEF)
|
||
|
num_sections = x[0].sh_size;
|
||
|
else
|
||
|
num_sections = hdr->e_shnum;
|
||
|
|
||
|
for (i = 1; i < num_sections; i++)
|
||
|
if (x[i].sh_type == SHT_SYMTAB)
|
||
|
return &x[i];
|
||
|
return NULL;
|
||
|
}
|
||
|
|
||
|
static void *map_file(char *file_name, int *size)
|
||
|
{
|
||
|
struct stat st;
|
||
|
void *map;
|
||
|
int fd;
|
||
|
|
||
|
fd = open(file_name, O_RDWR);
|
||
|
if (fd < 0) {
|
||
|
perror(file_name);
|
||
|
return NULL;
|
||
|
}
|
||
|
if (fstat(fd, &st)) {
|
||
|
perror("Could not determine file size");
|
||
|
close(fd);
|
||
|
return NULL;
|
||
|
}
|
||
|
*size = st.st_size;
|
||
|
map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
|
||
|
if (map == MAP_FAILED) {
|
||
|
perror("Mapping to memory failed");
|
||
|
close(fd);
|
||
|
return NULL;
|
||
|
}
|
||
|
close(fd);
|
||
|
return map;
|
||
|
}
|
||
|
|
||
|
static char *read_file(char *file_name, int *size)
|
||
|
{
|
||
|
struct stat st;
|
||
|
char *buf;
|
||
|
int fd;
|
||
|
|
||
|
fd = open(file_name, O_RDONLY);
|
||
|
if (fd < 0) {
|
||
|
perror(file_name);
|
||
|
return NULL;
|
||
|
}
|
||
|
if (fstat(fd, &st)) {
|
||
|
perror("Could not determine file size");
|
||
|
close(fd);
|
||
|
return NULL;
|
||
|
}
|
||
|
*size = st.st_size;
|
||
|
buf = malloc(*size);
|
||
|
if (!buf) {
|
||
|
perror("Allocating memory failed");
|
||
|
close(fd);
|
||
|
return NULL;
|
||
|
}
|
||
|
if (read(fd, buf, *size) != *size) {
|
||
|
perror("File read failed");
|
||
|
close(fd);
|
||
|
return NULL;
|
||
|
}
|
||
|
close(fd);
|
||
|
return buf;
|
||
|
}
|
||
|
|
||
|
static void print_sym(Elf_Ehdr *hdr, struct sym *s)
|
||
|
{
|
||
|
info("sym: %s\n", s->name);
|
||
|
info("addr: 0x%lx\n", s->address);
|
||
|
info("size: %d\n", s->size);
|
||
|
info("offset: 0x%lx\n", (unsigned long)s->offset);
|
||
|
}
|
||
|
|
||
|
static void print_usage(char *e)
|
||
|
{
|
||
|
printf("Usage %s [-s <System.map>] -b <vmlinux> -c <certfile>\n", e);
|
||
|
}
|
||
|
|
||
|
int main(int argc, char **argv)
|
||
|
{
|
||
|
char *system_map_file = NULL;
|
||
|
char *vmlinux_file = NULL;
|
||
|
char *cert_file = NULL;
|
||
|
int vmlinux_size;
|
||
|
int cert_size;
|
||
|
Elf_Ehdr *hdr;
|
||
|
char *cert;
|
||
|
FILE *system_map;
|
||
|
unsigned long *lsize;
|
||
|
int *used;
|
||
|
int opt;
|
||
|
Elf_Shdr *symtab = NULL;
|
||
|
struct sym cert_sym, lsize_sym, used_sym;
|
||
|
|
||
|
while ((opt = getopt(argc, argv, "b:c:s:")) != -1) {
|
||
|
switch (opt) {
|
||
|
case 's':
|
||
|
system_map_file = optarg;
|
||
|
break;
|
||
|
case 'b':
|
||
|
vmlinux_file = optarg;
|
||
|
break;
|
||
|
case 'c':
|
||
|
cert_file = optarg;
|
||
|
break;
|
||
|
default:
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (!vmlinux_file || !cert_file) {
|
||
|
print_usage(argv[0]);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
cert = read_file(cert_file, &cert_size);
|
||
|
if (!cert)
|
||
|
exit(EXIT_FAILURE);
|
||
|
|
||
|
hdr = map_file(vmlinux_file, &vmlinux_size);
|
||
|
if (!hdr)
|
||
|
exit(EXIT_FAILURE);
|
||
|
|
||
|
if (vmlinux_size < sizeof(*hdr)) {
|
||
|
err("Invalid ELF file.\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
|
||
|
(hdr->e_ident[EI_MAG1] != ELFMAG1) ||
|
||
|
(hdr->e_ident[EI_MAG2] != ELFMAG2) ||
|
||
|
(hdr->e_ident[EI_MAG3] != ELFMAG3)) {
|
||
|
err("Invalid ELF magic.\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
if (hdr->e_ident[EI_CLASS] != CURRENT_ELFCLASS) {
|
||
|
err("ELF class mismatch.\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
if (hdr->e_ident[EI_DATA] != endianness()) {
|
||
|
err("ELF endian mismatch.\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
if (hdr->e_shoff > vmlinux_size) {
|
||
|
err("Could not find section header.\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
symtab = get_symbol_table(hdr);
|
||
|
if (!symtab) {
|
||
|
warn("Could not find the symbol table.\n");
|
||
|
if (!system_map_file) {
|
||
|
err("Please provide a System.map file.\n");
|
||
|
print_usage(argv[0]);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
system_map = fopen(system_map_file, "r");
|
||
|
if (!system_map) {
|
||
|
perror(system_map_file);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
get_symbol_from_map(hdr, system_map, CERT_SYM, &cert_sym);
|
||
|
get_symbol_from_map(hdr, system_map, USED_SYM, &used_sym);
|
||
|
get_symbol_from_map(hdr, system_map, LSIZE_SYM, &lsize_sym);
|
||
|
cert_sym.size = used_sym.address - cert_sym.address;
|
||
|
} else {
|
||
|
info("Symbol table found.\n");
|
||
|
if (system_map_file)
|
||
|
warn("System.map is ignored.\n");
|
||
|
get_symbol_from_table(hdr, symtab, CERT_SYM, &cert_sym);
|
||
|
get_symbol_from_table(hdr, symtab, USED_SYM, &used_sym);
|
||
|
get_symbol_from_table(hdr, symtab, LSIZE_SYM, &lsize_sym);
|
||
|
}
|
||
|
|
||
|
if (!cert_sym.offset || !lsize_sym.offset || !used_sym.offset)
|
||
|
exit(EXIT_FAILURE);
|
||
|
|
||
|
print_sym(hdr, &cert_sym);
|
||
|
print_sym(hdr, &used_sym);
|
||
|
print_sym(hdr, &lsize_sym);
|
||
|
|
||
|
lsize = (unsigned long *)lsize_sym.content;
|
||
|
used = (int *)used_sym.content;
|
||
|
|
||
|
if (cert_sym.size < cert_size) {
|
||
|
err("Certificate is larger than the reserved area!\n");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
/* If the existing cert is the same, don't overwrite */
|
||
|
if (cert_size == *used &&
|
||
|
strncmp(cert_sym.content, cert, cert_size) == 0) {
|
||
|
warn("Certificate was already inserted.\n");
|
||
|
exit(EXIT_SUCCESS);
|
||
|
}
|
||
|
|
||
|
if (*used > 0)
|
||
|
warn("Replacing previously inserted certificate.\n");
|
||
|
|
||
|
memcpy(cert_sym.content, cert, cert_size);
|
||
|
if (cert_size < cert_sym.size)
|
||
|
memset(cert_sym.content + cert_size,
|
||
|
0, cert_sym.size - cert_size);
|
||
|
|
||
|
*lsize = *lsize + cert_size - *used;
|
||
|
*used = cert_size;
|
||
|
info("Inserted the contents of %s into %lx.\n", cert_file,
|
||
|
cert_sym.address);
|
||
|
info("Used %d bytes out of %d bytes reserved.\n", *used,
|
||
|
cert_sym.size);
|
||
|
exit(EXIT_SUCCESS);
|
||
|
}
|