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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "cpio.h"
#include "measure.h"
#include "util.h"
static CHAR8* write_cpio_word(CHAR8 *p, UINT32 v) {
static const char hex[] = "0123456789abcdef";
assert(p);
/* Writes a CPIO header 8 character hex value */
for (UINTN i = 0; i < 8; i++)
p[7-i] = hex[(v >> (4 * i)) & 0xF];
return p + 8;
}
static CHAR8* mangle_filename(CHAR8 *p, const CHAR16 *f) {
CHAR8* w;
assert(p);
assert(f);
/* Basically converts UTF-16 to plain ASCII (note that we filtered non-ASCII filenames beforehand, so
* this operation is always safe) */
for (w = p; *f != 0; f++) {
assert(*f <= 0x7fu);
*(w++) = *f;
}
*(w++) = 0;
return w;
}
static CHAR8* pad4(CHAR8 *p, const CHAR8* start) {
assert(p);
assert(start);
assert(p >= start);
/* Appends NUL bytes to 'p', until the address is divisible by 4, when taken relative to 'start' */
while ((p - start) % 4 != 0)
*(p++) = 0;
return p;
}
static EFI_STATUS pack_cpio_one(
const CHAR16 *fname,
const void *contents,
UINTN contents_size,
const CHAR8 *target_dir_prefix,
UINT32 access_mode,
UINT32 *inode_counter,
void **cpio_buffer,
UINTN *cpio_buffer_size) {
UINTN l, target_dir_prefix_size, fname_size, q;
CHAR8 *a;
assert(fname);
assert(contents_size || contents_size == 0);
assert(target_dir_prefix);
assert(inode_counter);
assert(cpio_buffer);
assert(cpio_buffer_size);
/* Serializes one file in the cpio format understood by the kernel initrd logic.
*
* See: https://www.kernel.org/doc/Documentation/early-userspace/buffer-format.txt */
if (contents_size > UINT32_MAX) /* cpio cannot deal with > 32bit file sizes */
return EFI_LOAD_ERROR;
if (*inode_counter == UINT32_MAX) /* more than 2^32-1 inodes? yikes. cpio doesn't support that either */
return EFI_OUT_OF_RESOURCES;
l = 6 + 13*8 + 1 + 1; /* Fixed CPIO header size, slash separator, and NUL byte after the file name*/
target_dir_prefix_size = strlena(target_dir_prefix);
if (l > UINTN_MAX - target_dir_prefix_size)
return EFI_OUT_OF_RESOURCES;
l += target_dir_prefix_size;
fname_size = StrLen(fname);
if (l > UINTN_MAX - fname_size)
return EFI_OUT_OF_RESOURCES;
l += fname_size; /* append space for file name */
/* CPIO can't deal with fnames longer than 2^32-1 */
if (target_dir_prefix_size + fname_size >= UINT32_MAX)
return EFI_OUT_OF_RESOURCES;
/* Align the whole header to 4 byte size */
l = ALIGN_TO(l, 4);
if (l == UINTN_MAX) /* overflow check */
return EFI_OUT_OF_RESOURCES;
/* Align the contents to 4 byte size */
q = ALIGN_TO(contents_size, 4);
if (q == UINTN_MAX) /* overflow check */
return EFI_OUT_OF_RESOURCES;
if (l > UINTN_MAX - q) /* overflow check */
return EFI_OUT_OF_RESOURCES;
l += q; /* Add contents to header */
if (*cpio_buffer_size > UINTN_MAX - l) /* overflow check */
return EFI_OUT_OF_RESOURCES;
a = xreallocate_pool(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + l);
*cpio_buffer = a;
a = (CHAR8*) *cpio_buffer + *cpio_buffer_size;
CopyMem(a, "070701", 6); /* magic ID */
a += 6;
a = write_cpio_word(a, (*inode_counter)++); /* inode */
a = write_cpio_word(a, access_mode | 0100000 /* = S_IFREG */); /* mode */
a = write_cpio_word(a, 0); /* uid */
a = write_cpio_word(a, 0); /* gid */
a = write_cpio_word(a, 1); /* nlink */
/* Note: we don't make any attempt to propagate the mtime here, for two reasons: it's a mess given
* that FAT usually is assumed to operate with timezoned timestamps, while UNIX does not. More
* importantly though: the modifications times would hamper our goals of providing stable
* measurements for the same boots. After all we extend the initrds we generate here into TPM2
* PCRs. */
a = write_cpio_word(a, 0); /* mtime */
a = write_cpio_word(a, contents_size); /* size */
a = write_cpio_word(a, 0); /* major(dev) */
a = write_cpio_word(a, 0); /* minor(dev) */
a = write_cpio_word(a, 0); /* major(rdev) */
a = write_cpio_word(a, 0); /* minor(rdev) */
a = write_cpio_word(a, target_dir_prefix_size + fname_size + 2); /* fname size */
a = write_cpio_word(a, 0); /* "crc" */
CopyMem(a, target_dir_prefix, target_dir_prefix_size);
a += target_dir_prefix_size;
*(a++) = '/';
a = mangle_filename(a, fname);
/* Pad to next multiple of 4 */
a = pad4(a, *cpio_buffer);
CopyMem(a, contents, contents_size);
a += contents_size;
/* Pad to next multiple of 4 */
a = pad4(a, *cpio_buffer);
assert(a == (CHAR8*) *cpio_buffer + *cpio_buffer_size + l);
*cpio_buffer_size += l;
return EFI_SUCCESS;
}
static EFI_STATUS pack_cpio_dir(
const CHAR8 *path,
UINT32 access_mode,
UINT32 *inode_counter,
void **cpio_buffer,
UINTN *cpio_buffer_size) {
UINTN l, path_size;
CHAR8 *a;
assert(path);
assert(inode_counter);
assert(cpio_buffer);
assert(cpio_buffer_size);
/* Serializes one directory inode in cpio format. Note that cpio archives must first create the dirs
* they want to place files in. */
if (*inode_counter == UINT32_MAX)
return EFI_OUT_OF_RESOURCES;
l = 6 + 13*8 + 1; /* Fixed CPIO header size, and NUL byte after the file name*/
path_size = strlena(path);
if (l > UINTN_MAX - path_size)
return EFI_OUT_OF_RESOURCES;
l += path_size;
/* Align the whole header to 4 byte size */
l = ALIGN_TO(l, 4);
if (l == UINTN_MAX) /* overflow check */
return EFI_OUT_OF_RESOURCES;
if (*cpio_buffer_size > UINTN_MAX - l) /* overflow check */
return EFI_OUT_OF_RESOURCES;
*cpio_buffer = a = xreallocate_pool(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + l);
a = (CHAR8*) *cpio_buffer + *cpio_buffer_size;
CopyMem(a, "070701", 6); /* magic ID */
a += 6;
a = write_cpio_word(a, (*inode_counter)++); /* inode */
a = write_cpio_word(a, access_mode | 0040000 /* = S_IFDIR */); /* mode */
a = write_cpio_word(a, 0); /* uid */
a = write_cpio_word(a, 0); /* gid */
a = write_cpio_word(a, 1); /* nlink */
a = write_cpio_word(a, 0); /* mtime */
a = write_cpio_word(a, 0); /* size */
a = write_cpio_word(a, 0); /* major(dev) */
a = write_cpio_word(a, 0); /* minor(dev) */
a = write_cpio_word(a, 0); /* major(rdev) */
a = write_cpio_word(a, 0); /* minor(rdev) */
a = write_cpio_word(a, path_size + 1); /* fname size */
a = write_cpio_word(a, 0); /* "crc" */
CopyMem(a, path, path_size + 1);
a += path_size + 1;
/* Pad to next multiple of 4 */
a = pad4(a, *cpio_buffer);
assert(a == (CHAR8*) *cpio_buffer + *cpio_buffer_size + l);
*cpio_buffer_size += l;
return EFI_SUCCESS;
}
static EFI_STATUS pack_cpio_prefix(
const CHAR8 *path,
UINT32 dir_mode,
UINT32 *inode_counter,
void **cpio_buffer,
UINTN *cpio_buffer_size) {
EFI_STATUS err;
assert(path);
assert(inode_counter);
assert(cpio_buffer);
assert(cpio_buffer_size);
/* Serializes directory inodes of all prefix paths of the specified path in cpio format. Note that
* (similar to mkdir -p behaviour) all leading paths are created with 0555 access mode, only the
* final dir is created with the specified directory access mode. */
for (const CHAR8 *p = path;;) {
const CHAR8 *e;
e = strchra(p, '/');
if (!e)
break;
if (e > p) {
_cleanup_freepool_ CHAR8 *t = NULL;
t = xstrndup8(path, e - path);
if (!t)
return EFI_OUT_OF_RESOURCES;
err = pack_cpio_dir(t, 0555, inode_counter, cpio_buffer, cpio_buffer_size);
if (EFI_ERROR(err))
return err;
}
p = e + 1;
}
return pack_cpio_dir(path, dir_mode, inode_counter, cpio_buffer, cpio_buffer_size);
}
static EFI_STATUS pack_cpio_trailer(
void **cpio_buffer,
UINTN *cpio_buffer_size) {
static const char trailer[] =
"070701"
"00000000"
"00000000"
"00000000"
"00000000"
"00000001"
"00000000"
"00000000"
"00000000"
"00000000"
"00000000"
"00000000"
"0000000B"
"00000000"
"TRAILER!!!\0\0\0"; /* There's a fourth NUL byte appended here, because this is a string */
/* Generates the cpio trailer record that indicates the end of our initrd cpio archive */
assert(cpio_buffer);
assert(cpio_buffer_size);
assert_cc(sizeof(trailer) % 4 == 0);
*cpio_buffer = xreallocate_pool(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + sizeof(trailer));
CopyMem((UINT8*) *cpio_buffer + *cpio_buffer_size, trailer, sizeof(trailer));
*cpio_buffer_size += sizeof(trailer);
return EFI_SUCCESS;
}
EFI_STATUS pack_cpio(
EFI_LOADED_IMAGE *loaded_image,
const CHAR16 *dropin_dir,
const CHAR16 *match_suffix,
const CHAR8 *target_dir_prefix,
UINT32 dir_mode,
UINT32 access_mode,
UINTN tpm_pcr,
const CHAR16 *tpm_description,
void **ret_buffer,
UINTN *ret_buffer_size) {
_cleanup_(file_handle_closep) EFI_FILE_HANDLE root = NULL, extra_dir = NULL;
UINTN dirent_size = 0, buffer_size = 0, n_items = 0, n_allocated = 0;
_cleanup_freepool_ CHAR16 *rel_dropin_dir = NULL;
_cleanup_freepool_ EFI_FILE_INFO *dirent = NULL;
_cleanup_(strv_freep) CHAR16 **items = NULL;
_cleanup_freepool_ void *buffer = NULL;
UINT32 inode = 1; /* inode counter, so that each item gets a new inode */
EFI_STATUS err;
assert(loaded_image);
assert(target_dir_prefix);
assert(ret_buffer);
assert(ret_buffer_size);
if (!loaded_image->DeviceHandle) {
*ret_buffer = NULL;
*ret_buffer_size = 0;
return EFI_SUCCESS;
}
root = LibOpenRoot(loaded_image->DeviceHandle);
if (!root)
return log_error_status_stall(EFI_LOAD_ERROR, L"Unable to open root directory.");
if (!dropin_dir)
dropin_dir = rel_dropin_dir = xpool_print(L"%D.extra.d", loaded_image->FilePath);
err = open_directory(root, dropin_dir, &extra_dir);
if (err == EFI_NOT_FOUND) {
/* No extra subdir, that's totally OK */
*ret_buffer = NULL;
*ret_buffer_size = 0;
return EFI_SUCCESS;
}
if (EFI_ERROR(err))
return log_error_status_stall(err, L"Failed to open extra directory of loaded image: %r", err);
for (;;) {
_cleanup_freepool_ CHAR16 *d = NULL;
err = readdir_harder(extra_dir, &dirent, &dirent_size);
if (EFI_ERROR(err))
return log_error_status_stall(err, L"Failed to read extra directory of loaded image: %r", err);
if (!dirent) /* End of directory */
break;
if (dirent->FileName[0] == '.')
continue;
if (FLAGS_SET(dirent->Attribute, EFI_FILE_DIRECTORY))
continue;
if (match_suffix && !endswith_no_case(dirent->FileName, match_suffix))
continue;
if (!is_ascii(dirent->FileName))
continue;
if (StrLen(dirent->FileName) > 255) /* Max filename size on Linux */
continue;
d = xstrdup(dirent->FileName);
if (n_items+2 > n_allocated) {
UINTN m;
/* We allocate 16 entries at a time, as a matter of optimization */
if (n_items > (UINTN_MAX / sizeof(UINT16)) - 16) /* Overflow check, just in case */
return log_oom();
m = n_items + 16;
items = xreallocate_pool(items, n_allocated * sizeof(UINT16*), m * sizeof(UINT16*));
n_allocated = m;
}
items[n_items++] = TAKE_PTR(d);
items[n_items] = NULL; /* Let's always NUL terminate, to make freeing via strv_free() easy */
}
if (n_items == 0) {
/* Empty directory */
*ret_buffer = NULL;
*ret_buffer_size = 0;
return EFI_SUCCESS;
}
/* Now, sort the files we found, to make this uniform and stable (and to ensure the TPM measurements
* are not dependent on read order) */
sort_pointer_array((void**) items, n_items, (compare_pointer_func_t) StrCmp);
/* Generate the leading directory inodes right before adding the first files, to the
* archive. Otherwise the cpio archive cannot be unpacked, since the leading dirs won't exist. */
err = pack_cpio_prefix(target_dir_prefix, dir_mode, &inode, &buffer, &buffer_size);
if (EFI_ERROR(err))
return log_error_status_stall(err, L"Failed to pack cpio prefix: %r", err);
for (UINTN i = 0; i < n_items; i++) {
_cleanup_freepool_ CHAR8 *content = NULL;
UINTN contentsize;
err = file_read(extra_dir, items[i], 0, 0, &content, &contentsize);
if (EFI_ERROR(err)) {
log_error_status_stall(err, L"Failed to read %s, ignoring: %r", items[i], err);
continue;
}
err = pack_cpio_one(
items[i],
content, contentsize,
target_dir_prefix,
access_mode,
&inode,
&buffer, &buffer_size);
if (EFI_ERROR(err))
return log_error_status_stall(err, L"Failed to pack cpio file %s: %r", dirent->FileName, err);
}
err = pack_cpio_trailer(&buffer, &buffer_size);
if (EFI_ERROR(err))
return log_error_status_stall(err, L"Failed to pack cpio trailer: %r");
err = tpm_log_event(
tpm_pcr,
POINTER_TO_PHYSICAL_ADDRESS(buffer),
buffer_size,
tpm_description);
if (EFI_ERROR(err))
log_error_stall(L"Unable to add initrd TPM measurement for PCR %u (%s), ignoring: %r", tpm_pcr, tpm_description, err);
*ret_buffer = TAKE_PTR(buffer);
*ret_buffer_size = buffer_size;
return EFI_SUCCESS;
}
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