1 files changed, 382 insertions, 0 deletions
diff --git a/src/utils_blockdev.c b/src/utils_blockdev.c
new file mode 100644
index 0000000..ae6dec4
--- /dev/null
+++ b/src/utils_blockdev.c
@@ -0,0 +1,382 @@
+/*
+ * Linux block devices helpers
+ *
+ * Copyright (C) 2018-2023 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2018-2023 Ondrej Kozina
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "cryptsetup.h"
+#include <dirent.h>
+#ifdef HAVE_SYS_SYSMACROS_H
+# include <sys/sysmacros.h>     /* for major, minor */
+#endif
+#include <uuid/uuid.h>
+
+#define UUID_LEN 37 /* 36 + \0, libuuid ... */
+
+static int dm_prepare_uuid(const char *type, const char *uuid, char *buf, size_t buflen)
+{
+	char *ptr, uuid2[UUID_LEN] = {0};
+	uuid_t uu;
+	unsigned i = 0;
+
+	/* Remove '-' chars */
+	if (uuid) {
+		if (uuid_parse(uuid, uu) < 0) {
+			log_dbg("Requested UUID %s has invalid format.", uuid);
+			return 0;
+		}
+
+		for (ptr = uuid2, i = 0; i < UUID_LEN; i++)
+			if (uuid[i] != '-') {
+				*ptr = uuid[i];
+				ptr++;
+			}
+	}
+
+	if (snprintf(buf, buflen, DM_UUID_PREFIX "%s%s%s%s",
+	    type ?: "", type ? "-" : "",
+	    uuid2[0] ? uuid2 : "", uuid2[0] ? "-" : "") < 0)
+		return 0;
+
+	return 1;
+}
+
+/* return number of holders in general, if matched dm_uuid prefix it's returned via dm_name */
+/* negative value is error */
+static int lookup_holder_dm_name(const char *dm_uuid, dev_t devno, char **r_dm_name)
+{
+	struct dirent *entry;
+	char dm_subpath[PATH_MAX], data_dev_dir[PATH_MAX], uuid[DM_UUID_LEN], dm_name[PATH_MAX] = {};
+	ssize_t s;
+	struct stat st;
+	int dmfd, fd, len, r = 0; /* not found */
+	DIR *dir;
+
+	if (!r_dm_name)
+		return -EINVAL;
+
+	len = snprintf(data_dev_dir, PATH_MAX, "/sys/dev/block/%u:%u/holders", major(devno), minor(devno));
+	if (len < 0 || len >= PATH_MAX)
+		return -EINVAL;
+
+	if (!(dir = opendir(data_dev_dir)))
+		/* map ENOTDIR to ENOENT we'll handle both errors same */
+		return errno == ENOTDIR ? -ENOENT : -errno;
+
+	while (r != 1 && (entry = readdir(dir))) {
+		if (entry->d_name[0] == '.' ||
+		    !strncmp(entry->d_name, "..", 2))
+			continue;
+
+		/* there's a holder */
+		r++;
+
+		/* we already have a dm_name, just count remaining holders */
+		if (*dm_name != '\0')
+			continue;
+
+		len = snprintf(dm_subpath, PATH_MAX, "%s/%s", entry->d_name, "dm");
+		if (len < 0 || len >= PATH_MAX) {
+			r = -EINVAL;
+			break;
+		}
+
+		/* looking for dm-X/dm directory, symlinks are fine */
+		dmfd = openat(dirfd(dir), dm_subpath, O_DIRECTORY | O_RDONLY);
+		if (dmfd < 0)
+			continue;
+
+		fd = openat(dmfd, "uuid", O_RDONLY);
+		if (fd < 0) {
+			close(dmfd);
+			continue;
+		}
+
+		if (fstat(fd, &st) || !S_ISREG(st.st_mode)) {
+			close(fd);
+			close(dmfd);
+			continue;
+		}
+
+		/* reads binary data */
+		s = read_buffer(fd, uuid, sizeof(uuid) - 1);
+		close(fd);
+		uuid[s > 0 ? s : 0] = '\0';
+		if (!strncmp(uuid, dm_uuid, strlen(dm_uuid)))
+			log_dbg("Found candidate device %s", entry->d_name);
+		else {
+			close(dmfd);
+			continue;
+		}
+
+		fd = openat(dmfd, "name", O_RDONLY);
+		if (fd < 0) {
+			close(dmfd);
+			continue;
+		}
+
+		if (fstat(fd, &st) || !S_ISREG(st.st_mode)) {
+			close(fd);
+			close(dmfd);
+			continue;
+		}
+
+		/* reads binary data */
+		s = read_buffer(fd, dm_name, sizeof(dm_name));
+		close(fd);
+		close(dmfd);
+		if (s > 1) {
+			dm_name[s-1] = '\0';
+			log_dbg("Found dm device %s", dm_name);
+			if (!(*r_dm_name = strdup(dm_name)))
+				return -ENOMEM;
+		}
+	}
+
+	closedir(dir);
+
+	return r;
+}
+
+int tools_lookup_crypt_device(struct crypt_device *cd, const char *type,
+		const char *data_device_path, char **r_name)
+{
+	char *c;
+	struct stat st;
+	char dev_uuid[DM_UUID_LEN + DM_BY_ID_PREFIX_LEN] = DM_BY_ID_PREFIX;
+
+	if (!dm_prepare_uuid(type, crypt_get_uuid(cd), dev_uuid + DM_BY_ID_PREFIX_LEN, DM_UUID_LEN))
+		return -EINVAL;
+
+	c = strrchr(dev_uuid, '-');
+	if (!c)
+		return -EINVAL;
+
+	/* cut of dm name */
+	*c = '\0';
+
+	log_dbg("Looking for any dm device with prefix: %s", dev_uuid);
+
+	if (stat(data_device_path, &st) < 0)
+		return -ENODEV;
+
+	if (!S_ISBLK(st.st_mode))
+		return -ENOTBLK;
+
+	return lookup_holder_dm_name(dev_uuid + DM_BY_ID_PREFIX_LEN, st.st_rdev, r_name);
+}
+
+static void report_partition(const char *value, const char *device, bool batch_mode)
+{
+	if (batch_mode)
+		log_dbg("Device %s already contains a '%s' partition signature.", device, value);
+	else
+		log_std(_("WARNING: Device %s already contains a '%s' partition signature.\n"), device, value);
+}
+
+static void report_superblock(const char *value, const char *device, bool batch_mode)
+{
+	if (batch_mode)
+		log_dbg("Device %s already contains a '%s' superblock signature.", device, value);
+	else
+		log_std(_("WARNING: Device %s already contains a '%s' superblock signature.\n"), device, value);
+}
+
+int tools_detect_signatures(const char *device, tools_probe_filter_info filter,
+		size_t *count,bool batch_mode)
+{
+	int r;
+	size_t tmp_count;
+	struct blkid_handle *h;
+	blk_probe_status pr;
+
+	if (!count)
+		count = &tmp_count;
+
+	*count = 0;
+
+	if (!blk_supported()) {
+		log_dbg("Blkid support disabled.");
+		return 0;
+	}
+
+	if ((r = blk_init_by_path(&h, device))) {
+		log_err(_("Failed to initialize device signature probes."));
+		return -EINVAL;
+	}
+
+	switch (filter) {
+	case PRB_FILTER_LUKS:
+		if (blk_superblocks_filter_luks(h)) {
+			r = -EINVAL;
+			goto out;
+		}
+		/* fall-through */
+	case PRB_FILTER_NONE:
+		blk_set_chains_for_full_print(h);
+		break;
+	case PRB_ONLY_LUKS:
+		blk_set_chains_for_fast_detection(h);
+		if (blk_superblocks_only_luks(h)) {
+			r = -EINVAL;
+			goto out;
+		}
+	}
+
+	while ((pr = blk_probe(h)) < PRB_EMPTY) {
+		if (blk_is_partition(h))
+			report_partition(blk_get_partition_type(h), device, batch_mode);
+		else if (blk_is_superblock(h))
+			report_superblock(blk_get_superblock_type(h), device, batch_mode);
+		else {
+			log_dbg("Internal tools_detect_signatures() error.");
+			r = -EINVAL;
+			goto out;
+		}
+		(*count)++;
+	}
+
+	if (pr == PRB_FAIL)
+		r = -EINVAL;
+out:
+	blk_free(h);
+	return r;
+}
+
+int tools_wipe_all_signatures(const char *path, bool exclusive, bool only_luks)
+{
+	int fd, flags, r;
+	blk_probe_status pr;
+	struct stat st;
+	struct blkid_handle *h = NULL;
+
+	if (!blk_supported()) {
+		log_dbg("Blkid support disabled.");
+		return 0;
+	}
+
+	if (stat(path, &st)) {
+		log_err(_("Failed to stat device %s."), path);
+		return -EINVAL;
+	}
+
+	flags = O_RDWR;
+	if (S_ISBLK(st.st_mode) && exclusive)
+		flags |= O_EXCL;
+
+	/* better than opening regular file with O_EXCL (undefined) */
+	/* coverity[toctou] */
+	fd = open(path, flags); /* lgtm[cpp/toctou-race-condition] */
+	if (fd < 0) {
+		if (errno == EBUSY)
+			log_err(_("Cannot exclusively open %s, device in use."), path);
+		else
+			log_err(_("Failed to open file %s in read/write mode."), path);
+		return -EINVAL;
+	}
+
+	if ((r = blk_init_by_fd(&h, fd))) {
+		log_err(_("Failed to initialize device signature probes."));
+		r = -EINVAL;
+		goto out;
+	}
+
+	blk_set_chains_for_wipes(h);
+	if (only_luks && (r = blk_superblocks_only_luks(h))) {
+		r = -EINVAL;
+		goto out;
+	}
+
+	while ((pr = blk_probe(h)) < PRB_EMPTY) {
+		if (blk_is_partition(h))
+			log_verbose(_("Existing '%s' partition signature on device %s will be wiped."),
+				    blk_get_partition_type(h), path);
+		if (blk_is_superblock(h))
+			log_verbose(_("Existing '%s' superblock signature on device %s will be wiped."),
+				    blk_get_superblock_type(h), path);
+		if (blk_do_wipe(h) || fsync(fd)) {
+			log_err(_("Failed to wipe device signature."));
+			r = -EINVAL;
+			goto out;
+		}
+	}
+
+	if (pr != PRB_EMPTY) {
+		log_err(_("Failed to probe device %s for a signature."), path);
+		r = -EINVAL;
+	}
+out:
+	close(fd);
+	blk_free(h);
+	return r;
+}
+
+int tools_superblock_block_size(const char *device, char *sb_name, size_t sb_name_len, unsigned *r_block_size)
+{
+	struct blkid_handle *h;
+	const char *name;
+	int r = 0;
+
+	if (!r_block_size || !sb_name || sb_name_len < 1)
+		return -EINVAL;
+
+	if (!blk_supported()) {
+		log_dbg("Blkid support disabled.");
+		return 0;
+	}
+
+	if ((r = blk_init_by_path(&h, device))) {
+		log_err(_("Failed to initialize device signature probes."));
+		return -EINVAL;
+	}
+
+	blk_set_chains_for_superblocks(h);
+
+	switch (blk_probe(h)) {
+	case PRB_OK:
+		*r_block_size = blk_get_block_size(h);
+		if (!*r_block_size) /* same as not-found */
+			break;
+
+		if (!(name = blk_get_superblock_type(h))) {
+			r = -EINVAL;
+			break;
+		}
+
+		/* we don't mind truncating */
+		strncpy(sb_name, name, sb_name_len - 1);
+		sb_name[sb_name_len-1] = '\0';
+
+		log_dbg("Detected superblock %s on device %s (block size: %u).", sb_name, device, *r_block_size);
+		r = 1;
+		/* fall-through */
+	case PRB_EMPTY:
+		break;
+	default:
+		r = -EINVAL;
+	}
+
+	blk_free(h);
+
+	return r;
+}
+
+bool tools_blkid_supported(void)
+{
+	return blk_supported() != 0;
+}