/* 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_t 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_t access_mode, uint32_t *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 = strlen8((const char *) target_dir_prefix); if (l > UINTN_MAX - target_dir_prefix_size) return EFI_OUT_OF_RESOURCES; l += target_dir_prefix_size; fname_size = strlen16(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 = ALIGN4(l); if (l == UINTN_MAX) /* overflow check */ return EFI_OUT_OF_RESOURCES; /* Align the contents to 4 byte size */ q = ALIGN4(contents_size); 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 = xrealloc(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + l); *cpio_buffer = a; a = (CHAR8*) *cpio_buffer + *cpio_buffer_size; memcpy(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" */ memcpy(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); memcpy(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_t access_mode, uint32_t *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 = strlen8((const char *) path); if (l > UINTN_MAX - path_size) return EFI_OUT_OF_RESOURCES; l += path_size; /* Align the whole header to 4 byte size */ l = ALIGN4(l); 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 = xrealloc(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + l); a = (CHAR8*) *cpio_buffer + *cpio_buffer_size; memcpy(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" */ memcpy(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_t dir_mode, uint32_t *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 = (const CHAR8 *) strchr8((const char *) p, '/'); if (!e) break; if (e > p) { _cleanup_freepool_ CHAR8 *t = NULL; t = (CHAR8 *) xstrndup8((const char *) path, e - path); if (!t) return EFI_OUT_OF_RESOURCES; err = pack_cpio_dir(t, 0555, inode_counter, cpio_buffer, cpio_buffer_size); if (err != EFI_SUCCESS) 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 = xrealloc(*cpio_buffer, *cpio_buffer_size, *cpio_buffer_size + sizeof(trailer)); memcpy((uint8_t*) *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_t dir_mode, uint32_t access_mode, const uint32_t tpm_pcr[], UINTN n_tpm_pcr, const CHAR16 *tpm_description, void **ret_buffer, UINTN *ret_buffer_size) { _cleanup_(file_closep) EFI_FILE *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_t inode = 1; /* inode counter, so that each item gets a new inode */ EFI_STATUS err; EFI_FILE_IO_INTERFACE *volume; assert(loaded_image); assert(target_dir_prefix); assert(tpm_pcr || n_tpm_pcr == 0); assert(ret_buffer); assert(ret_buffer_size); if (!loaded_image->DeviceHandle) { *ret_buffer = NULL; *ret_buffer_size = 0; return EFI_SUCCESS; } err = BS->HandleProtocol(loaded_image->DeviceHandle, &FileSystemProtocol, (void*)&volume); /* Error will be unsupported if the bootloader doesn't implement the * file system protocol on its file handles. */ if (err == EFI_UNSUPPORTED) { *ret_buffer = NULL; *ret_buffer_size = 0; return EFI_SUCCESS; } if (err != EFI_SUCCESS) return log_error_status_stall( err, L"Unable to load file system protocol: %r", err); err = volume->OpenVolume(volume, &root); if (err != EFI_SUCCESS) return log_error_status_stall( err, L"Unable to open root directory: %r", err); 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 (err != EFI_SUCCESS) 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 (err != EFI_SUCCESS) 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 (strlen16(dirent->FileName) > 255) /* Max filename size on Linux */ continue; d = xstrdup16(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_t)) - 16) /* Overflow check, just in case */ return log_oom(); m = n_items + 16; items = xrealloc(items, n_allocated * sizeof(uint16_t *), m * sizeof(uint16_t *)); 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) strcmp16); /* 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 (err != EFI_SUCCESS) 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 (err != EFI_SUCCESS) { 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 (err != EFI_SUCCESS) 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 (err != EFI_SUCCESS) return log_error_status_stall(err, L"Failed to pack cpio trailer: %r"); for (UINTN i = 0; i < n_tpm_pcr; i++) { err = tpm_log_event( tpm_pcr[i], POINTER_TO_PHYSICAL_ADDRESS(buffer), buffer_size, tpm_description); if (err != EFI_SUCCESS) log_error_stall(L"Unable to add initrd TPM measurement for PCR %u (%s), ignoring: %r", tpm_pcr[i], tpm_description, err); } *ret_buffer = TAKE_PTR(buffer); *ret_buffer_size = buffer_size; return EFI_SUCCESS; }