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Systemd/src/shared/dissect-image.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2016 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include "sd-id128.h"
#include "architecture.h"
#include "ask-password-api.h"
#include "blkid-util.h"
#include "blockdev-util.h"
#include "copy.h"
#include "crypt-util.h"
#include "def.h"
#include "device-nodes.h"
#include "dissect-image.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "gpt.h"
#include "hexdecoct.h"
#include "hostname-util.h"
#include "id128-util.h"
#include "linux-3.13/dm-ioctl.h"
#include "missing.h"
#include "mount-util.h"
#include "path-util.h"
#include "process-util.h"
#include "raw-clone.h"
#include "signal-util.h"
#include "stat-util.h"
#include "stdio-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "udev-util.h"
#include "user-util.h"
#include "xattr-util.h"
int probe_filesystem(const char *node, char **ret_fstype) {
/* Try to find device content type and return it in *ret_fstype. If nothing is found,
* 0/NULL will be returned. -EUCLEAN will be returned for ambigous results, and an
* different error otherwise. */
#if HAVE_BLKID
_cleanup_blkid_free_probe_ blkid_probe b = NULL;
const char *fstype;
int r;
errno = 0;
b = blkid_new_probe_from_filename(node);
if (!b)
return -errno ?: -ENOMEM;
blkid_probe_enable_superblocks(b, 1);
blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE);
errno = 0;
r = blkid_do_safeprobe(b);
if (r == 1) {
log_debug("No type detected on partition %s", node);
goto not_found;
}
if (r == -2) {
log_debug("Results ambiguous for partition %s", node);
return -EUCLEAN;
}
if (r != 0)
return -errno ?: -EIO;
(void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
if (fstype) {
char *t;
t = strdup(fstype);
if (!t)
return -ENOMEM;
*ret_fstype = t;
return 1;
}
not_found:
*ret_fstype = NULL;
return 0;
#else
return -EOPNOTSUPP;
#endif
}
int dissect_image(
int fd,
const void *root_hash,
size_t root_hash_size,
DissectImageFlags flags,
DissectedImage **ret) {
#if HAVE_BLKID
sd_id128_t root_uuid = SD_ID128_NULL, verity_uuid = SD_ID128_NULL;
_cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
bool is_gpt, is_mbr, generic_rw, multiple_generic = false;
_cleanup_udev_device_unref_ struct udev_device *d = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
_cleanup_blkid_free_probe_ blkid_probe b = NULL;
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_free_ char *generic_node = NULL;
sd_id128_t generic_uuid = SD_ID128_NULL;
const char *pttype = NULL;
struct udev_list_entry *first, *item;
blkid_partlist pl;
int r, generic_nr;
struct stat st;
unsigned i;
assert(fd >= 0);
assert(ret);
assert(root_hash || root_hash_size == 0);
/* Probes a disk image, and returns information about what it found in *ret.
*
* Returns -ENOPKG if no suitable partition table or file system could be found.
* Returns -EADDRNOTAVAIL if a root hash was specified but no matching root/verity partitions found. */
if (root_hash) {
/* If a root hash is supplied, then we use the root partition that has a UUID that match the first
* 128bit of the root hash. And we use the verity partition that has a UUID that match the final
* 128bit. */
if (root_hash_size < sizeof(sd_id128_t))
return -EINVAL;
memcpy(&root_uuid, root_hash, sizeof(sd_id128_t));
memcpy(&verity_uuid, (const uint8_t*) root_hash + root_hash_size - sizeof(sd_id128_t), sizeof(sd_id128_t));
if (sd_id128_is_null(root_uuid))
return -EINVAL;
if (sd_id128_is_null(verity_uuid))
return -EINVAL;
}
if (fstat(fd, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENOTBLK;
b = blkid_new_probe();
if (!b)
return -ENOMEM;
errno = 0;
r = blkid_probe_set_device(b, fd, 0, 0);
if (r != 0)
return -errno ?: -ENOMEM;
if ((flags & DISSECT_IMAGE_GPT_ONLY) == 0) {
/* Look for file system superblocks, unless we only shall look for GPT partition tables */
blkid_probe_enable_superblocks(b, 1);
blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE|BLKID_SUBLKS_USAGE);
}
blkid_probe_enable_partitions(b, 1);
blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
errno = 0;
r = blkid_do_safeprobe(b);
if (IN_SET(r, -2, 1)) {
log_debug("Failed to identify any partition table.");
return -ENOPKG;
}
if (r != 0)
return -errno ?: -EIO;
m = new0(DissectedImage, 1);
if (!m)
return -ENOMEM;
if (!(flags & DISSECT_IMAGE_GPT_ONLY) &&
(flags & DISSECT_IMAGE_REQUIRE_ROOT)) {
const char *usage = NULL;
(void) blkid_probe_lookup_value(b, "USAGE", &usage, NULL);
if (STRPTR_IN_SET(usage, "filesystem", "crypto")) {
_cleanup_free_ char *t = NULL, *n = NULL;
const char *fstype = NULL;
/* OK, we have found a file system, that's our root partition then. */
(void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
if (fstype) {
t = strdup(fstype);
if (!t)
return -ENOMEM;
}
if (asprintf(&n, "/dev/block/%u:%u", major(st.st_rdev), minor(st.st_rdev)) < 0)
return -ENOMEM;
m->partitions[PARTITION_ROOT] = (DissectedPartition) {
.found = true,
.rw = true,
.partno = -1,
.architecture = _ARCHITECTURE_INVALID,
.fstype = t,
.node = n,
};
t = n = NULL;
m->encrypted = streq(fstype, "crypto_LUKS");
*ret = m;
m = NULL;
return 0;
}
}
(void) blkid_probe_lookup_value(b, "PTTYPE", &pttype, NULL);
if (!pttype)
return -ENOPKG;
is_gpt = streq_ptr(pttype, "gpt");
is_mbr = streq_ptr(pttype, "dos");
if (!is_gpt && ((flags & DISSECT_IMAGE_GPT_ONLY) || !is_mbr))
return -ENOPKG;
errno = 0;
pl = blkid_probe_get_partitions(b);
if (!pl)
return -errno ?: -ENOMEM;
udev = udev_new();
if (!udev)
return -errno;
d = udev_device_new_from_devnum(udev, 'b', st.st_rdev);
if (!d)
return -ENOMEM;
for (i = 0;; i++) {
int n, z;
if (i >= 10) {
log_debug("Kernel partitions never appeared.");
return -ENXIO;
}
e = udev_enumerate_new(udev);
if (!e)
return -errno;
r = udev_enumerate_add_match_parent(e, d);
if (r < 0)
return r;
r = udev_enumerate_scan_devices(e);
if (r < 0)
return r;
/* Count the partitions enumerated by the kernel */
n = 0;
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first)
n++;
/* Count the partitions enumerated by blkid */
z = blkid_partlist_numof_partitions(pl);
if (n == z + 1)
break;
if (n > z + 1) {
log_debug("blkid and kernel partition list do not match.");
return -EIO;
}
if (n < z + 1) {
unsigned j = 0;
/* The kernel has probed fewer partitions than blkid? Maybe the kernel prober is still running
* or it got EBUSY because udev already opened the device. Let's reprobe the device, which is a
* synchronous call that waits until probing is complete. */
for (;;) {
if (j++ > 20)
return -EBUSY;
if (ioctl(fd, BLKRRPART, 0) < 0) {
r = -errno;
if (r == -EINVAL) {
struct loop_info64 info;
/* If we are running on a loop device that has partition scanning off,
* return an explicit recognizable error about this, so that callers
* can generate a proper message explaining the situation. */
if (ioctl(fd, LOOP_GET_STATUS64, &info) >= 0 && (info.lo_flags & LO_FLAGS_PARTSCAN) == 0) {
log_debug("Device is loop device and partition scanning is off!");
return -EPROTONOSUPPORT;
}
}
if (r != -EBUSY)
return r;
} else
break;
/* If something else has the device open, such as an udev rule, the ioctl will return
* EBUSY. Since there's no way to wait until it isn't busy anymore, let's just wait a
* bit, and try again.
*
* This is really something they should fix in the kernel! */
(void) usleep(50 * USEC_PER_MSEC);
}
}
e = udev_enumerate_unref(e);
}
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first) {
_cleanup_udev_device_unref_ struct udev_device *q;
unsigned long long pflags;
blkid_partition pp;
const char *node, *sysname;
dev_t qn;
int nr;
q = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
if (!q)
return -errno;
qn = udev_device_get_devnum(q);
if (major(qn) == 0)
continue;
if (st.st_rdev == qn)
continue;
/* Filter out weird MMC RPMB partitions, which cannot reasonably be read, see
* https://github.com/systemd/systemd/issues/5806 */
sysname = udev_device_get_sysname(q);
if (sysname && startswith(sysname, "mmcblk") &&
(endswith(sysname, "rpmb") || endswith(sysname, "boot0" ) || endswith(sysname, "boot1")))
continue;
node = udev_device_get_devnode(q);
if (!node)
continue;
pp = blkid_partlist_devno_to_partition(pl, qn);
if (!pp)
continue;
pflags = blkid_partition_get_flags(pp);
nr = blkid_partition_get_partno(pp);
if (nr < 0)
continue;
if (is_gpt) {
int designator = _PARTITION_DESIGNATOR_INVALID, architecture = _ARCHITECTURE_INVALID;
const char *stype, *sid, *fstype = NULL;
sd_id128_t type_id, id;
bool rw = true;
sid = blkid_partition_get_uuid(pp);
if (!sid)
continue;
if (sd_id128_from_string(sid, &id) < 0)
continue;
stype = blkid_partition_get_type_string(pp);
if (!stype)
continue;
if (sd_id128_from_string(stype, &type_id) < 0)
continue;
if (sd_id128_equal(type_id, GPT_HOME)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
designator = PARTITION_HOME;
rw = !(pflags & GPT_FLAG_READ_ONLY);
} else if (sd_id128_equal(type_id, GPT_SRV)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
designator = PARTITION_SRV;
rw = !(pflags & GPT_FLAG_READ_ONLY);
} else if (sd_id128_equal(type_id, GPT_ESP)) {
/* Note that we don't check the GPT_FLAG_NO_AUTO flag for the ESP, as it is not defined
* there. We instead check the GPT_FLAG_NO_BLOCK_IO_PROTOCOL, as recommended by the
* UEFI spec (See "12.3.3 Number and Location of System Partitions"). */
if (pflags & GPT_FLAG_NO_BLOCK_IO_PROTOCOL)
continue;
designator = PARTITION_ESP;
fstype = "vfat";
}
#ifdef GPT_ROOT_NATIVE
else if (sd_id128_equal(type_id, GPT_ROOT_NATIVE)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
/* If a root ID is specified, ignore everything but the root id */
if (!sd_id128_is_null(root_uuid) && !sd_id128_equal(root_uuid, id))
continue;
designator = PARTITION_ROOT;
architecture = native_architecture();
rw = !(pflags & GPT_FLAG_READ_ONLY);
} else if (sd_id128_equal(type_id, GPT_ROOT_NATIVE_VERITY)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
m->can_verity = true;
/* Ignore verity unless a root hash is specified */
if (sd_id128_is_null(verity_uuid) || !sd_id128_equal(verity_uuid, id))
continue;
designator = PARTITION_ROOT_VERITY;
fstype = "DM_verity_hash";
architecture = native_architecture();
rw = false;
}
#endif
#ifdef GPT_ROOT_SECONDARY
else if (sd_id128_equal(type_id, GPT_ROOT_SECONDARY)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
/* If a root ID is specified, ignore everything but the root id */
if (!sd_id128_is_null(root_uuid) && !sd_id128_equal(root_uuid, id))
continue;
designator = PARTITION_ROOT_SECONDARY;
architecture = SECONDARY_ARCHITECTURE;
rw = !(pflags & GPT_FLAG_READ_ONLY);
} else if (sd_id128_equal(type_id, GPT_ROOT_SECONDARY_VERITY)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
m->can_verity = true;
/* Ignore verity unless root has is specified */
if (sd_id128_is_null(verity_uuid) || !sd_id128_equal(verity_uuid, id))
continue;
designator = PARTITION_ROOT_SECONDARY_VERITY;
fstype = "DM_verity_hash";
architecture = SECONDARY_ARCHITECTURE;
rw = false;
}
#endif
else if (sd_id128_equal(type_id, GPT_SWAP)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
designator = PARTITION_SWAP;
fstype = "swap";
} else if (sd_id128_equal(type_id, GPT_LINUX_GENERIC)) {
if (pflags & GPT_FLAG_NO_AUTO)
continue;
if (generic_node)
multiple_generic = true;
else {
generic_nr = nr;
generic_rw = !(pflags & GPT_FLAG_READ_ONLY);
generic_uuid = id;
generic_node = strdup(node);
if (!generic_node)
return -ENOMEM;
}
}
if (designator != _PARTITION_DESIGNATOR_INVALID) {
_cleanup_free_ char *t = NULL, *n = NULL;
/* First one wins */
if (m->partitions[designator].found)
continue;
if (fstype) {
t = strdup(fstype);
if (!t)
return -ENOMEM;
}
n = strdup(node);
if (!n)
return -ENOMEM;
m->partitions[designator] = (DissectedPartition) {
.found = true,
.partno = nr,
.rw = rw,
.architecture = architecture,
.node = n,
.fstype = t,
.uuid = id,
};
n = t = NULL;
}
} else if (is_mbr) {
if (pflags != 0x80) /* Bootable flag */
continue;
if (blkid_partition_get_type(pp) != 0x83) /* Linux partition */
continue;
if (generic_node)
multiple_generic = true;
else {
generic_nr = nr;
generic_rw = true;
generic_node = strdup(node);
if (!generic_node)
return -ENOMEM;
}
}
}
if (!m->partitions[PARTITION_ROOT].found) {
/* No root partition found? Then let's see if ther's one for the secondary architecture. And if not
* either, then check if there's a single generic one, and use that. */
if (m->partitions[PARTITION_ROOT_VERITY].found)
return -EADDRNOTAVAIL;
if (m->partitions[PARTITION_ROOT_SECONDARY].found) {
m->partitions[PARTITION_ROOT] = m->partitions[PARTITION_ROOT_SECONDARY];
zero(m->partitions[PARTITION_ROOT_SECONDARY]);
m->partitions[PARTITION_ROOT_VERITY] = m->partitions[PARTITION_ROOT_SECONDARY_VERITY];
zero(m->partitions[PARTITION_ROOT_SECONDARY_VERITY]);
} else if (flags & DISSECT_IMAGE_REQUIRE_ROOT) {
/* If the root has was set, then we won't fallback to a generic node, because the root hash
* decides */
if (root_hash)
return -EADDRNOTAVAIL;
/* If we didn't find a generic node, then we can't fix this up either */
if (!generic_node)
return -ENXIO;
/* If we didn't find a properly marked root partition, but we did find a single suitable
* generic Linux partition, then use this as root partition, if the caller asked for it. */
if (multiple_generic)
return -ENOTUNIQ;
m->partitions[PARTITION_ROOT] = (DissectedPartition) {
.found = true,
.rw = generic_rw,
.partno = generic_nr,
.architecture = _ARCHITECTURE_INVALID,
.node = generic_node,
.uuid = generic_uuid,
};
generic_node = NULL;
}
}
if (root_hash) {
if (!m->partitions[PARTITION_ROOT_VERITY].found || !m->partitions[PARTITION_ROOT].found)
return -EADDRNOTAVAIL;
/* If we found the primary root with the hash, then we definitely want to suppress any secondary root
* (which would be weird, after all the root hash should only be assigned to one pair of
* partitions... */
m->partitions[PARTITION_ROOT_SECONDARY].found = false;
m->partitions[PARTITION_ROOT_SECONDARY_VERITY].found = false;
/* If we found a verity setup, then the root partition is necessarily read-only. */
m->partitions[PARTITION_ROOT].rw = false;
m->verity = true;
}
blkid_free_probe(b);
b = NULL;
/* Fill in file system types if we don't know them yet. */
for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
DissectedPartition *p = m->partitions + i;
if (!p->found)
continue;
if (!p->fstype && p->node) {
r = probe_filesystem(p->node, &p->fstype);
if (r < 0 && r != -EUCLEAN)
return r;
}
if (streq_ptr(p->fstype, "crypto_LUKS"))
m->encrypted = true;
if (p->fstype && fstype_is_ro(p->fstype))
p->rw = false;
}
*ret = m;
m = NULL;
return 0;
#else
return -EOPNOTSUPP;
#endif
}
DissectedImage* dissected_image_unref(DissectedImage *m) {
unsigned i;
if (!m)
return NULL;
for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
free(m->partitions[i].fstype);
free(m->partitions[i].node);
free(m->partitions[i].decrypted_fstype);
free(m->partitions[i].decrypted_node);
}
free(m->hostname);
strv_free(m->machine_info);
strv_free(m->os_release);
return mfree(m);
}
static int is_loop_device(const char *path) {
char s[SYS_BLOCK_PATH_MAX("/../loop/")];
struct stat st;
assert(path);
if (stat(path, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENOTBLK;
xsprintf_sys_block_path(s, "/loop/", st.st_dev);
if (access(s, F_OK) < 0) {
if (errno != ENOENT)
return -errno;
/* The device itself isn't a loop device, but maybe it's a partition and its parent is? */
xsprintf_sys_block_path(s, "/../loop/", st.st_dev);
if (access(s, F_OK) < 0)
return errno == ENOENT ? false : -errno;
}
return true;
}
static int mount_partition(
DissectedPartition *m,
const char *where,
const char *directory,
uid_t uid_shift,
DissectImageFlags flags) {
_cleanup_free_ char *chased = NULL, *options = NULL;
const char *p, *node, *fstype;
bool rw;
int r;
assert(m);
assert(where);
node = m->decrypted_node ?: m->node;
fstype = m->decrypted_fstype ?: m->fstype;
if (!m->found || !node || !fstype)
return 0;
/* Stacked encryption? Yuck */
if (streq_ptr(fstype, "crypto_LUKS"))
return -ELOOP;
rw = m->rw && !(flags & DISSECT_IMAGE_READ_ONLY);
if (directory) {
r = chase_symlinks(directory, where, CHASE_PREFIX_ROOT, &chased);
if (r < 0)
return r;
p = chased;
} else
p = where;
/* If requested, turn on discard support. */
if (fstype_can_discard(fstype) &&
((flags & DISSECT_IMAGE_DISCARD) ||
((flags & DISSECT_IMAGE_DISCARD_ON_LOOP) && is_loop_device(m->node)))) {
options = strdup("discard");
if (!options)
return -ENOMEM;
}
if (uid_is_valid(uid_shift) && uid_shift != 0 && fstype_can_uid_gid(fstype)) {
_cleanup_free_ char *uid_option = NULL;
if (asprintf(&uid_option, "uid=" UID_FMT ",gid=" GID_FMT, uid_shift, (gid_t) uid_shift) < 0)
return -ENOMEM;
if (!strextend_with_separator(&options, ",", uid_option, NULL))
return -ENOMEM;
}
return mount_verbose(LOG_DEBUG, node, p, fstype, MS_NODEV|(rw ? 0 : MS_RDONLY), options);
}
int dissected_image_mount(DissectedImage *m, const char *where, uid_t uid_shift, DissectImageFlags flags) {
int r;
assert(m);
assert(where);
if (!m->partitions[PARTITION_ROOT].found)
return -ENXIO;
if ((flags & DISSECT_IMAGE_MOUNT_NON_ROOT_ONLY) == 0) {
r = mount_partition(m->partitions + PARTITION_ROOT, where, NULL, uid_shift, flags);
if (r < 0)
return r;
}
if ((flags & DISSECT_IMAGE_MOUNT_ROOT_ONLY))
return 0;
r = mount_partition(m->partitions + PARTITION_HOME, where, "/home", uid_shift, flags);
if (r < 0)
return r;
r = mount_partition(m->partitions + PARTITION_SRV, where, "/srv", uid_shift, flags);
if (r < 0)
return r;
if (m->partitions[PARTITION_ESP].found) {
const char *mp;
/* Mount the ESP to /efi if it exists and is empty. If it doesn't exist, use /boot instead. */
FOREACH_STRING(mp, "/efi", "/boot") {
_cleanup_free_ char *p = NULL;
r = chase_symlinks(mp, where, CHASE_PREFIX_ROOT, &p);
if (r < 0)
continue;
r = dir_is_empty(p);
if (r > 0) {
r = mount_partition(m->partitions + PARTITION_ESP, where, mp, uid_shift, flags);
if (r < 0)
return r;
}
}
}
return 0;
}
#if HAVE_LIBCRYPTSETUP
typedef struct DecryptedPartition {
struct crypt_device *device;
char *name;
bool relinquished;
} DecryptedPartition;
struct DecryptedImage {
DecryptedPartition *decrypted;
size_t n_decrypted;
size_t n_allocated;
};
#endif
DecryptedImage* decrypted_image_unref(DecryptedImage* d) {
#if HAVE_LIBCRYPTSETUP
size_t i;
int r;
if (!d)
return NULL;
for (i = 0; i < d->n_decrypted; i++) {
DecryptedPartition *p = d->decrypted + i;
if (p->device && p->name && !p->relinquished) {
r = crypt_deactivate(p->device, p->name);
if (r < 0)
log_debug_errno(r, "Failed to deactivate encrypted partition %s", p->name);
}
if (p->device)
crypt_free(p->device);
free(p->name);
}
free(d);
#endif
return NULL;
}
#if HAVE_LIBCRYPTSETUP
static int make_dm_name_and_node(const void *original_node, const char *suffix, char **ret_name, char **ret_node) {
_cleanup_free_ char *name = NULL, *node = NULL;
const char *base;
assert(original_node);
assert(suffix);
assert(ret_name);
assert(ret_node);
base = strrchr(original_node, '/');
if (!base)
return -EINVAL;
base++;
if (isempty(base))
return -EINVAL;
name = strjoin(base, suffix);
if (!name)
return -ENOMEM;
if (!filename_is_valid(name))
return -EINVAL;
node = strjoin(crypt_get_dir(), "/", name);
if (!node)
return -ENOMEM;
*ret_name = name;
*ret_node = node;
name = node = NULL;
return 0;
}
static int decrypt_partition(
DissectedPartition *m,
const char *passphrase,
DissectImageFlags flags,
DecryptedImage *d) {
_cleanup_free_ char *node = NULL, *name = NULL;
_cleanup_(crypt_freep) struct crypt_device *cd = NULL;
int r;
assert(m);
assert(d);
if (!m->found || !m->node || !m->fstype)
return 0;
if (!streq(m->fstype, "crypto_LUKS"))
return 0;
if (!passphrase)
return -ENOKEY;
r = make_dm_name_and_node(m->node, "-decrypted", &name, &node);
if (r < 0)
return r;
if (!GREEDY_REALLOC0(d->decrypted, d->n_allocated, d->n_decrypted + 1))
return -ENOMEM;
r = crypt_init(&cd, m->node);
if (r < 0)
return log_debug_errno(r, "Failed to initialize dm-crypt: %m");
r = crypt_load(cd, CRYPT_LUKS, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to load LUKS metadata: %m");
r = crypt_activate_by_passphrase(cd, name, CRYPT_ANY_SLOT, passphrase, strlen(passphrase),
((flags & DISSECT_IMAGE_READ_ONLY) ? CRYPT_ACTIVATE_READONLY : 0) |
((flags & DISSECT_IMAGE_DISCARD_ON_CRYPTO) ? CRYPT_ACTIVATE_ALLOW_DISCARDS : 0));
if (r < 0) {
log_debug_errno(r, "Failed to activate LUKS device: %m");
return r == -EPERM ? -EKEYREJECTED : r;
}
d->decrypted[d->n_decrypted].name = name;
name = NULL;
d->decrypted[d->n_decrypted].device = cd;
cd = NULL;
d->n_decrypted++;
m->decrypted_node = node;
node = NULL;
return 0;
}
static int verity_partition(
DissectedPartition *m,
DissectedPartition *v,
const void *root_hash,
size_t root_hash_size,
DissectImageFlags flags,
DecryptedImage *d) {
_cleanup_free_ char *node = NULL, *name = NULL;
_cleanup_(crypt_freep) struct crypt_device *cd = NULL;
int r;
assert(m);
assert(v);
if (!root_hash)
return 0;
if (!m->found || !m->node || !m->fstype)
return 0;
if (!v->found || !v->node || !v->fstype)
return 0;
if (!streq(v->fstype, "DM_verity_hash"))
return 0;
r = make_dm_name_and_node(m->node, "-verity", &name, &node);
if (r < 0)
return r;
if (!GREEDY_REALLOC0(d->decrypted, d->n_allocated, d->n_decrypted + 1))
return -ENOMEM;
r = crypt_init(&cd, v->node);
if (r < 0)
return r;
r = crypt_load(cd, CRYPT_VERITY, NULL);
if (r < 0)
return r;
r = crypt_set_data_device(cd, m->node);
if (r < 0)
return r;
r = crypt_activate_by_volume_key(cd, name, root_hash, root_hash_size, CRYPT_ACTIVATE_READONLY);
if (r < 0)
return r;
d->decrypted[d->n_decrypted].name = name;
name = NULL;
d->decrypted[d->n_decrypted].device = cd;
cd = NULL;
d->n_decrypted++;
m->decrypted_node = node;
node = NULL;
return 0;
}
#endif
int dissected_image_decrypt(
DissectedImage *m,
const char *passphrase,
const void *root_hash,
size_t root_hash_size,
DissectImageFlags flags,
DecryptedImage **ret) {
#if HAVE_LIBCRYPTSETUP
_cleanup_(decrypted_image_unrefp) DecryptedImage *d = NULL;
unsigned i;
int r;
#endif
assert(m);
assert(root_hash || root_hash_size == 0);
/* Returns:
*
* = 0 → There was nothing to decrypt
* > 0 → Decrypted successfully
* -ENOKEY → There's something to decrypt but no key was supplied
* -EKEYREJECTED → Passed key was not correct
*/
if (root_hash && root_hash_size < sizeof(sd_id128_t))
return -EINVAL;
if (!m->encrypted && !m->verity) {
*ret = NULL;
return 0;
}
#if HAVE_LIBCRYPTSETUP
d = new0(DecryptedImage, 1);
if (!d)
return -ENOMEM;
for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
DissectedPartition *p = m->partitions + i;
int k;
if (!p->found)
continue;
r = decrypt_partition(p, passphrase, flags, d);
if (r < 0)
return r;
k = PARTITION_VERITY_OF(i);
if (k >= 0) {
r = verity_partition(p, m->partitions + k, root_hash, root_hash_size, flags, d);
if (r < 0)
return r;
}
if (!p->decrypted_fstype && p->decrypted_node) {
r = probe_filesystem(p->decrypted_node, &p->decrypted_fstype);
if (r < 0 && r != -EUCLEAN)
return r;
}
}
*ret = d;
d = NULL;
return 1;
#else
return -EOPNOTSUPP;
#endif
}
int dissected_image_decrypt_interactively(
DissectedImage *m,
const char *passphrase,
const void *root_hash,
size_t root_hash_size,
DissectImageFlags flags,
DecryptedImage **ret) {
_cleanup_strv_free_erase_ char **z = NULL;
int n = 3, r;
if (passphrase)
n--;
for (;;) {
r = dissected_image_decrypt(m, passphrase, root_hash, root_hash_size, flags, ret);
if (r >= 0)
return r;
if (r == -EKEYREJECTED)
log_error_errno(r, "Incorrect passphrase, try again!");
else if (r != -ENOKEY) {
log_error_errno(r, "Failed to decrypt image: %m");
return r;
}
if (--n < 0) {
log_error("Too many retries.");
return -EKEYREJECTED;
}
z = strv_free(z);
r = ask_password_auto("Please enter image passphrase!", NULL, "dissect", "dissect", USEC_INFINITY, 0, &z);
if (r < 0)
return log_error_errno(r, "Failed to query for passphrase: %m");
passphrase = z[0];
}
}
#if HAVE_LIBCRYPTSETUP
static int deferred_remove(DecryptedPartition *p) {
struct dm_ioctl dm = {
.version = {
DM_VERSION_MAJOR,
DM_VERSION_MINOR,
DM_VERSION_PATCHLEVEL
},
.data_size = sizeof(dm),
.flags = DM_DEFERRED_REMOVE,
};
_cleanup_close_ int fd = -1;
assert(p);
/* Unfortunately, libcryptsetup doesn't provide a proper API for this, hence call the ioctl() directly. */
fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC);
if (fd < 0)
return -errno;
strncpy(dm.name, p->name, sizeof(dm.name));
if (ioctl(fd, DM_DEV_REMOVE, &dm))
return -errno;
return 0;
}
#endif
int decrypted_image_relinquish(DecryptedImage *d) {
#if HAVE_LIBCRYPTSETUP
size_t i;
int r;
#endif
assert(d);
/* Turns on automatic removal after the last use ended for all DM devices of this image, and sets a boolean so
* that we don't clean it up ourselves either anymore */
#if HAVE_LIBCRYPTSETUP
for (i = 0; i < d->n_decrypted; i++) {
DecryptedPartition *p = d->decrypted + i;
if (p->relinquished)
continue;
r = deferred_remove(p);
if (r < 0)
return log_debug_errno(r, "Failed to mark %s for auto-removal: %m", p->name);
p->relinquished = true;
}
#endif
return 0;
}
int root_hash_load(const char *image, void **ret, size_t *ret_size) {
_cleanup_free_ char *text = NULL;
_cleanup_free_ void *k = NULL;
size_t l;
int r;
assert(image);
assert(ret);
assert(ret_size);
if (is_device_path(image)) {
/* If we are asked to load the root hash for a device node, exit early */
*ret = NULL;
*ret_size = 0;
return 0;
}
r = getxattr_malloc(image, "user.verity.roothash", &text, true);
if (r < 0) {
char *fn, *e, *n;
if (!IN_SET(r, -ENODATA, -EOPNOTSUPP, -ENOENT))
return r;
fn = newa(char, strlen(image) + STRLEN(".roothash") + 1);
n = stpcpy(fn, image);
e = endswith(fn, ".raw");
if (e)
n = e;
strcpy(n, ".roothash");
r = read_one_line_file(fn, &text);
if (r == -ENOENT) {
*ret = NULL;
*ret_size = 0;
return 0;
}
if (r < 0)
return r;
}
r = unhexmem(text, strlen(text), &k, &l);
if (r < 0)
return r;
if (l < sizeof(sd_id128_t))
return -EINVAL;
*ret = k;
*ret_size = l;
k = NULL;
return 1;
}
int dissected_image_acquire_metadata(DissectedImage *m) {
enum {
META_HOSTNAME,
META_MACHINE_ID,
META_MACHINE_INFO,
META_OS_RELEASE,
_META_MAX,
};
static const char *const paths[_META_MAX] = {
[META_HOSTNAME] = "/etc/hostname\0",
[META_MACHINE_ID] = "/etc/machine-id\0",
[META_MACHINE_INFO] = "/etc/machine-info\0",
[META_OS_RELEASE] = "/etc/os-release\0/usr/lib/os-release\0",
};
_cleanup_strv_free_ char **machine_info = NULL, **os_release = NULL;
_cleanup_(rmdir_and_freep) char *t = NULL;
_cleanup_(sigkill_waitp) pid_t child = 0;
sd_id128_t machine_id = SD_ID128_NULL;
_cleanup_free_ char *hostname = NULL;
unsigned n_meta_initialized = 0, k;
int fds[2 * _META_MAX], r;
BLOCK_SIGNALS(SIGCHLD);
assert(m);
for (; n_meta_initialized < _META_MAX; n_meta_initialized ++)
if (pipe2(fds + 2*n_meta_initialized, O_CLOEXEC) < 0) {
r = -errno;
goto finish;
}
r = mkdtemp_malloc("/tmp/dissect-XXXXXX", &t);
if (r < 0)
goto finish;
r = safe_fork("(sd-dissect)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_NEW_MOUNTNS, &child);
if (r < 0)
goto finish;
if (r == 0) {
/* Make sure we never propagate to the host */
if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) < 0)
_exit(EXIT_FAILURE);
r = dissected_image_mount(m, t, UID_INVALID, DISSECT_IMAGE_READ_ONLY);
if (r < 0)
_exit(EXIT_FAILURE);
for (k = 0; k < _META_MAX; k++) {
_cleanup_close_ int fd = -1;
const char *p;
fds[2*k] = safe_close(fds[2*k]);
NULSTR_FOREACH(p, paths[k]) {
_cleanup_free_ char *q = NULL;
r = chase_symlinks(p, t, CHASE_PREFIX_ROOT, &q);
if (r < 0)
continue;
fd = open(q, O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd >= 0)
break;
}
if (fd < 0)
continue;
r = copy_bytes(fd, fds[2*k+1], (uint64_t) -1, 0);
if (r < 0)
_exit(EXIT_FAILURE);
fds[2*k+1] = safe_close(fds[2*k+1]);
}
_exit(EXIT_SUCCESS);
}
for (k = 0; k < _META_MAX; k++) {
_cleanup_fclose_ FILE *f = NULL;
fds[2*k+1] = safe_close(fds[2*k+1]);
f = fdopen(fds[2*k], "re");
if (!f) {
r = -errno;
goto finish;
}
fds[2*k] = -1;
switch (k) {
case META_HOSTNAME:
r = read_etc_hostname_stream(f, &hostname);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/hostname: %m");
break;
case META_MACHINE_ID: {
_cleanup_free_ char *line = NULL;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/machine-id: %m");
else if (r == 33) {
r = sd_id128_from_string(line, &machine_id);
if (r < 0)
log_debug_errno(r, "Image contains invalid /etc/machine-id: %s", line);
} else if (r == 0)
log_debug("/etc/machine-id file is empty.");
else
log_debug("/etc/machine-id has unexpected length %i.", r);
break;
}
case META_MACHINE_INFO:
r = load_env_file_pairs(f, "machine-info", NULL, &machine_info);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/machine-info: %m");
break;
case META_OS_RELEASE:
r = load_env_file_pairs(f, "os-release", NULL, &os_release);
if (r < 0)
log_debug_errno(r, "Failed to read OS release file: %m");
break;
}
}
r = wait_for_terminate_and_check("(sd-dissect)", child, 0);
child = 0;
if (r < 0)
goto finish;
if (r != EXIT_SUCCESS)
return -EPROTO;
free_and_replace(m->hostname, hostname);
m->machine_id = machine_id;
strv_free_and_replace(m->machine_info, machine_info);
strv_free_and_replace(m->os_release, os_release);
finish:
for (k = 0; k < n_meta_initialized; k++)
safe_close_pair(fds + 2*k);
return r;
}
int dissect_image_and_warn(
int fd,
const char *name,
const void *root_hash,
size_t root_hash_size,
DissectImageFlags flags,
DissectedImage **ret) {
_cleanup_free_ char *buffer = NULL;
int r;
if (!name) {
r = fd_get_path(fd, &buffer);
if (r < 0)
return r;
name = buffer;
}
r = dissect_image(fd, root_hash, root_hash_size, flags, ret);
switch (r) {
case -EOPNOTSUPP:
return log_error_errno(r, "Dissecting images is not supported, compiled without blkid support.");
case -ENOPKG:
return log_error_errno(r, "Couldn't identify a suitable partition table or file system in '%s'.", name);
case -EADDRNOTAVAIL:
return log_error_errno(r, "No root partition for specified root hash found in '%s'.", name);
case -ENOTUNIQ:
return log_error_errno(r, "Multiple suitable root partitions found in image '%s'.", name);
case -ENXIO:
return log_error_errno(r, "No suitable root partition found in image '%s'.", name);
case -EPROTONOSUPPORT:
return log_error_errno(r, "Device '%s' is loopback block device with partition scanning turned off, please turn it on.", name);
default:
if (r < 0)
return log_error_errno(r, "Failed to dissect image '%s': %m", name);
return r;
}
}
static const char *const partition_designator_table[] = {
[PARTITION_ROOT] = "root",
[PARTITION_ROOT_SECONDARY] = "root-secondary",
[PARTITION_HOME] = "home",
[PARTITION_SRV] = "srv",
[PARTITION_ESP] = "esp",
[PARTITION_SWAP] = "swap",
[PARTITION_ROOT_VERITY] = "root-verity",
[PARTITION_ROOT_SECONDARY_VERITY] = "root-secondary-verity",
};
DEFINE_STRING_TABLE_LOOKUP(partition_designator, int);
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