tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

UBUNTU: SAUCE: (noup) KEYS: Support for inserting a certificate into x86 bzImage

Browse Source 
BugLink: http://bugs.launchpad.net/bugs/1558553

The config option SYSTEM_EXTRA_CERTIFICATE reserves space in vmlinux file,
which is compressed to create the self-extracting bzImage. This patch adds the
capability of extracting the vmlinux, inserting the certificate, and
repackaging the result into a bzImage.

It only works if the resulting compressed vmlinux is smaller than the original.
Otherwise re-linking would be required. To make the reserved space allocate
actual space in bzImage, a null key is inserted into vmlinux before creating
the bzImage:

	make vmlinux
	scripts/insert-sys-cert -b vmlinux -c /dev/null
	make bzImage

After null key insertion, the script populates the rest of the reserved space
with random bytes, which have poor compression. After receiving a bzImage that
is created this way, actual certificate can be inserted into the bzImage:

	scripts/insert-sys-cert -s <System.map> -z <bzImage> -c <certfile>

Signed-off-by: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
This commit is contained in:
Mehmet Kayaalp
2016-03-10 16:22:13 -05:00
committed by Paolo Pisati
parent 5ac1fa5042
commit 1a011b4401
1 changed files with 203 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files
scripts/insert-sys-cert.c
+203 -7
View File
@@ -7,7 +7,8 @@
* 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>
* Usage: insert-sys-cert [-s <System.map>] -b <vmlinux> -c <certfile>
* [-s <System.map>] -z <bzImage> -c <certfile>
*/
#define _GNU_SOURCE
@@ -257,6 +258,169 @@ static char *read_file(char *file_name, int *size)
return buf;
}
static void get_payload_info(char *bzimage, int *offset, int *size)
{
unsigned int system_offset;
unsigned char setup_sectors;
setup_sectors = bzimage[0x1f1] + 1;
system_offset = setup_sectors * 512;
*offset = system_offset + *((int*)&bzimage[0x248]);
*size = *((int*)&bzimage[0x24c]);
}
static void update_payload_info(char* bzimage, int new_size)
{
int offset, size;
get_payload_info(bzimage, &offset, &size);
*((int*)&bzimage[0x24c]) = new_size;
if (new_size < size)
memset(bzimage + offset + new_size, 0, size - new_size);
}
struct zipper {
unsigned char pattern[10];
int length;
char *command;
char *compress;
};
struct zipper zippers[] = {
{{0x7F,'E','L','F'}, 4, "cat", "cat"},
{{0x1F,0x8B}, 2, "gunzip", "gzip -n -f -9"},
{{0xFD,'7','z','X','Z',0}, 6, "unxz", "xz"},
{{'B','Z','h'},3, "bunzip2", "bzip2 -9"},
{{0xFF,'L','Z','M','A',0}, 6, "unlzma", "lzma -9"},
{{0xD3,'L','Z','O',0,'\r','\n',0x20,'\n'}, 9, "lzop -d", "lzop -9"}
};
static struct zipper* get_zipper(char *p) {
int i;
for (i = 0; i < sizeof(zippers)/sizeof(struct zipper); i++) {
if (memcmp(p, zippers[i].pattern, zippers[i].length) == 0)
return &zippers[i];
}
return NULL;
}
/*
* This only works for x86 bzImage
*/
static void extract_vmlinux(char *bzimage, int bzimage_size,
char **file, struct zipper **zipper)
{
int r;
char src[15] = "vmlinux-XXXXXX";
char dest[15] = "vmlinux-XXXXXX";
char cmd[100];
int src_fd, dest_fd;
int offset, size;
struct zipper *z;
/* TODO: verify that bzImage is supported */
get_payload_info(bzimage, &offset, &size);
z = get_zipper(bzimage + offset);
if (z == NULL) {
err("Unable to determine the compression of vmlinux\n");
return;
}
src_fd = mkstemp(src);
if (src_fd == -1) {
perror("Could not create temp file");
return;
}
r = write(src_fd, bzimage + offset, size);
if (r != size) {
perror("Could not write vmlinux");
return;
}
dest_fd = mkstemp(dest);
if (dest_fd == -1) {
perror("Could not create temp file");
return;
}
snprintf(cmd, sizeof(cmd), "%s <%s >%s", z->command, src, dest);
info("Executing: %s\n", cmd);
r = system(cmd);
if (r!=0)
warn("Possible errors when extracting\n");
r = remove(src);
if (r!=0)
perror(src);
*file = strdup(dest);
*zipper = z;
}
static void repack_image(char *bzimage, int bzimage_size,
char* vmlinux_file, struct zipper *z)
{
char tmp[15] = "vmlinux-XXXXXX";
char cmd[100];
int fd;
struct stat st;
int new_size;
int r;
int offset, size;
get_payload_info(bzimage, &offset, &size);
fd = mkstemp(tmp);
if (fd == -1) {
perror("Could not create temp file");
return;
}
snprintf(cmd, sizeof(cmd), "%s <%s >%s",
z->compress, vmlinux_file, tmp);
info("Executing: %s\n", cmd);
r = system(cmd);
if (r!=0)
warn("Possible errors when compressing\n");
r = remove(vmlinux_file);
if (r!=0)
perror(vmlinux_file);
if (fstat(fd, &st)) {
perror("Could not determine file size");
close(fd);
}
new_size = st.st_size;
if (new_size > size) {
err("Increase in compressed size is not supported.\n");
err("Old size was %d, new size is %d\n", size, new_size);
exit(EXIT_FAILURE);
}
r = read(fd, bzimage + offset, new_size);
if (r != new_size)
perror(tmp);
r = remove(tmp);
if (r!=0)
perror(tmp);
/* x86 specific patching of bzimage */
update_payload_info(bzimage, new_size);
/* TODO: update CRC */
}
static void fill_random(unsigned char *p, int n) {
srand(0);
int i;
for (i = 0; i < n; i++)
p[i] = rand();
}
static void print_sym(Elf_Ehdr *hdr, struct sym *s)
{
info("sym: %s\n", s->name);
@@ -267,18 +431,23 @@ static void print_sym(Elf_Ehdr *hdr, struct sym *s)
static void print_usage(char *e)
{
printf("Usage %s [-s <System.map>] -b <vmlinux> -c <certfile>\n", e);
printf("Usage: %s [-s <System.map>] -b <vmlinux> -c <certfile>\n", e);
printf(" %s [-s <System.map>] -z <bzImage> -c <certfile>\n", e);
}
int main(int argc, char **argv)
{
char *system_map_file = NULL;
char *vmlinux_file = NULL;
char *bzimage_file = NULL;
char *cert_file = NULL;
int vmlinux_size;
int bzimage_size;
int cert_size;
Elf_Ehdr *hdr;
char *cert;
char *bzimage = NULL;
struct zipper *z = NULL;
FILE *system_map;
unsigned long *lsize;
int *used;
@@ -286,7 +455,7 @@ int main(int argc, char **argv)
Elf_Shdr *symtab = NULL;
struct sym cert_sym, lsize_sym, used_sym;
while ((opt = getopt(argc, argv, "b:c:s:")) != -1) {
while ((opt = getopt(argc, argv, "b:z:c:s:")) != -1) {
switch (opt) {
case 's':
system_map_file = optarg;
@@ -294,6 +463,9 @@ int main(int argc, char **argv)
case 'b':
vmlinux_file = optarg;
break;
case 'z':
bzimage_file = optarg;
break;
case 'c':
cert_file = optarg;
break;
@@ -302,7 +474,9 @@ int main(int argc, char **argv)
}
}
if (!vmlinux_file || !cert_file) {
if (!cert_file ||
(!vmlinux_file && !bzimage_file) ||
(vmlinux_file && bzimage_file)) {
print_usage(argv[0]);
exit(EXIT_FAILURE);
}
@@ -311,6 +485,16 @@ int main(int argc, char **argv)
if (!cert)
exit(EXIT_FAILURE);
if (bzimage_file) {
bzimage = map_file(bzimage_file, &bzimage_size);
if (!bzimage)
exit(EXIT_FAILURE);
extract_vmlinux(bzimage, bzimage_size, &vmlinux_file, &z);
if (!vmlinux_file)
exit(EXIT_FAILURE);
}
hdr = map_file(vmlinux_file, &vmlinux_size);
if (!hdr)
exit(EXIT_FAILURE);
@@ -386,7 +570,7 @@ int main(int argc, char **argv)
}
/* If the existing cert is the same, don't overwrite */
if (cert_size == *used &&
if (cert_size > 0 && cert_size == *used &&
strncmp(cert_sym.content, cert, cert_size) == 0) {
warn("Certificate was already inserted.\n");
exit(EXIT_SUCCESS);
@@ -396,9 +580,11 @@ int main(int argc, char **argv)
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);
/* This makes the reserved space incompressable */
fill_random(cert_sym.content + cert_size,
cert_sym.size - cert_size);
*lsize = *lsize + cert_size - *used;
*used = cert_size;
@@ -406,5 +592,15 @@ int main(int argc, char **argv)
cert_sym.address);
info("Used %d bytes out of %d bytes reserved.\n", *used,
cert_sym.size);
if (munmap(hdr, vmlinux_size) == -1) {
perror(vmlinux_file);
exit(EXIT_FAILURE);
}
if (bzimage) {
repack_image(bzimage, bzimage_size, vmlinux_file, z);
}
exit(EXIT_SUCCESS);
}