diff options
Diffstat (limited to 'lib/utils_device.c')
| -rw-r--r-- | lib/utils_device.c | 892 |
1 files changed, 892 insertions, 0 deletions
diff --git a/lib/utils_device.c b/lib/utils_device.c new file mode 100644 index 0000000..fbb1904 --- /dev/null +++ b/lib/utils_device.c @@ -0,0 +1,892 @@ +/* + * device backend utilities + * + * Copyright (C) 2004 Jana Saout <jana@saout.de> + * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2019 Red Hat, Inc. All rights reserved. + * Copyright (C) 2009-2019 Milan Broz + * + * 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 <assert.h> +#include <string.h> +#include <stdlib.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/ioctl.h> +#include <linux/fs.h> +#include <unistd.h> +#ifdef HAVE_SYS_SYSMACROS_H +# include <sys/sysmacros.h> /* for major, minor */ +#endif +#ifdef HAVE_SYS_STATVFS_H +# include <sys/statvfs.h> +#endif +#include "internal.h" +#include "utils_device_locking.h" + +struct device { + char *path; + + char *file_path; + int loop_fd; + + struct crypt_lock_handle *lh; + + unsigned int o_direct:1; + unsigned int init_done:1; /* path is bdev or loop already initialized */ + + /* cached values */ + size_t alignment; + size_t block_size; +}; + +static size_t device_fs_block_size_fd(int fd) +{ + size_t page_size = crypt_getpagesize(); + +#ifdef HAVE_SYS_STATVFS_H + struct statvfs buf; + + /* + * NOTE: some filesystems (NFS) returns bogus blocksize (1MB). + * Page-size io should always work and avoids increasing IO beyond aligned LUKS header. + */ + if (!fstatvfs(fd, &buf) && buf.f_bsize && buf.f_bsize <= page_size) + return (size_t)buf.f_bsize; +#endif + return page_size; +} + +static size_t device_block_size_fd(int fd, size_t *min_size) +{ + struct stat st; + size_t bsize; + int arg; + + if (fstat(fd, &st) < 0) + return 0; + + if (S_ISREG(st.st_mode)) + bsize = device_fs_block_size_fd(fd); + else { + if (ioctl(fd, BLKSSZGET, &arg) < 0) + bsize = crypt_getpagesize(); + else + bsize = (size_t)arg; + } + + if (!min_size) + return bsize; + + if (S_ISREG(st.st_mode)) { + /* file can be empty as well */ + if (st.st_size > (ssize_t)bsize) + *min_size = bsize; + else + *min_size = st.st_size; + } else { + /* block device must have at least one block */ + *min_size = bsize; + } + + return bsize; +} + +static size_t device_alignment_fd(int devfd) +{ + long alignment = DEFAULT_MEM_ALIGNMENT; + +#ifdef _PC_REC_XFER_ALIGN + alignment = fpathconf(devfd, _PC_REC_XFER_ALIGN); + if (alignment < 0) + alignment = DEFAULT_MEM_ALIGNMENT; +#endif + return (size_t)alignment; +} + +static int device_read_test(int devfd) +{ + char buffer[512]; + int r = -EIO; + size_t minsize = 0, blocksize, alignment; + + blocksize = device_block_size_fd(devfd, &minsize); + alignment = device_alignment_fd(devfd); + + if (!blocksize || !alignment) + return -EINVAL; + + if (minsize == 0) + return 0; + + if (minsize > sizeof(buffer)) + minsize = sizeof(buffer); + + if (read_blockwise(devfd, blocksize, alignment, buffer, minsize) == (ssize_t)minsize) + r = 0; + + crypt_memzero(buffer, sizeof(buffer)); + return r; +} + +/* + * The direct-io is always preferred. The header is usually mapped to the same + * device and can be accessed when the rest of device is mapped to data device. + * Using dirct-io encsures that we do not mess with data in cache. + * (But proper alignment should prevent this in the first place.) + * The read test is needed to detect broken configurations (seen with remote + * block devices) that allow open with direct-io but then fails on read. + */ +static int device_ready(struct crypt_device *cd, struct device *device) +{ + int devfd = -1, r = 0; + struct stat st; + size_t tmp_size; + + if (device->o_direct) { + log_dbg(cd, "Trying to open and read device %s with direct-io.", + device_path(device)); + device->o_direct = 0; + devfd = open(device_path(device), O_RDONLY | O_DIRECT); + if (devfd >= 0) { + if (device_read_test(devfd) == 0) { + device->o_direct = 1; + } else { + close(devfd); + devfd = -1; + } + } + } + + if (devfd < 0) { + log_dbg(cd, "Trying to open device %s without direct-io.", + device_path(device)); + devfd = open(device_path(device), O_RDONLY); + } + + if (devfd < 0) { + log_err(cd, _("Device %s doesn't exist or access denied."), + device_path(device)); + return -EINVAL; + } + + if (fstat(devfd, &st) < 0) + r = -EINVAL; + else if (!S_ISBLK(st.st_mode)) + r = S_ISREG(st.st_mode) ? -ENOTBLK : -EINVAL; + if (r == -EINVAL) { + log_err(cd, _("Device %s is not compatible."), + device_path(device)); + close(devfd); + return r; + } + + /* Allow only increase (loop device) */ + tmp_size = device_alignment_fd(devfd); + if (tmp_size > device->alignment) + device->alignment = tmp_size; + + tmp_size = device_block_size_fd(devfd, NULL); + if (tmp_size > device->block_size) + device->block_size = tmp_size; + + close(devfd); + return r; +} + +static int _open_locked(struct crypt_device *cd, struct device *device, int flags) +{ + int fd; + + log_dbg(cd, "Opening locked device %s", device_path(device)); + + if ((flags & O_ACCMODE) != O_RDONLY && device_locked_readonly(device->lh)) { + log_dbg(cd, "Can not open locked device %s in write mode. Read lock held.", device_path(device)); + return -EAGAIN; + } + + fd = open(device_path(device), flags); + if (fd < 0) + return -errno; + + if (device_locked_verify(cd, fd, device->lh)) { + /* fd doesn't correspond to a locked resource */ + close(fd); + log_dbg(cd, "Failed to verify lock resource for device %s.", device_path(device)); + return -EINVAL; + } + + return fd; +} + +/* + * Common wrapper for device sync. + * FIXME: file descriptor will be in struct later. + */ +void device_sync(struct crypt_device *cd, struct device *device, int devfd) +{ + if (fsync(devfd) == -1) + log_dbg(cd, "Cannot sync device %s.", device_path(device)); +} + +/* + * in non-locked mode returns always fd or -1 + * + * in locked mode: + * opened fd or one of: + * -EAGAIN : requested write mode while device being locked in via shared lock + * -EINVAL : invalid lock fd state + * -1 : all other errors + */ +static int device_open_internal(struct crypt_device *cd, struct device *device, int flags) +{ + int devfd; + + if (device->o_direct) + flags |= O_DIRECT; + + if (device_locked(device->lh)) + devfd = _open_locked(cd, device, flags); + else + devfd = open(device_path(device), flags); + + if (devfd < 0) + log_dbg(cd, "Cannot open device %s%s.", + device_path(device), + (flags & O_ACCMODE) != O_RDONLY ? " for write" : ""); + + return devfd; +} + +int device_open(struct crypt_device *cd, struct device *device, int flags) +{ + assert(!device_locked(device->lh)); + return device_open_internal(cd, device, flags); +} + +int device_open_locked(struct crypt_device *cd, struct device *device, int flags) +{ + assert(!crypt_metadata_locking_enabled() || device_locked(device->lh)); + return device_open_internal(cd, device, flags); +} + +/* Avoid any read from device, expects direct-io to work. */ +int device_alloc_no_check(struct device **device, const char *path) +{ + struct device *dev; + + if (!path) { + *device = NULL; + return 0; + } + + dev = malloc(sizeof(struct device)); + if (!dev) + return -ENOMEM; + + memset(dev, 0, sizeof(struct device)); + dev->path = strdup(path); + if (!dev->path) { + free(dev); + return -ENOMEM; + } + dev->loop_fd = -1; + dev->o_direct = 1; + + *device = dev; + return 0; +} + +int device_alloc(struct crypt_device *cd, struct device **device, const char *path) +{ + struct device *dev; + int r; + + r = device_alloc_no_check(&dev, path); + if (r < 0) + return r; + + if (dev) { + r = device_ready(cd, dev); + if (!r) { + dev->init_done = 1; + } else if (r == -ENOTBLK) { + /* alloc loop later */ + } else if (r < 0) { + free(dev->path); + free(dev); + return -ENOTBLK; + } + } + + *device = dev; + return 0; +} + +void device_free(struct crypt_device *cd, struct device *device) +{ + if (!device) + return; + + if (device->loop_fd != -1) { + log_dbg(cd, "Closed loop %s (%s).", device->path, device->file_path); + close(device->loop_fd); + } + + assert (!device_locked(device->lh)); + + free(device->file_path); + free(device->path); + free(device); +} + +/* Get block device path */ +const char *device_block_path(const struct device *device) +{ + if (!device || !device->init_done) + return NULL; + + return device->path; +} + +/* Get device-mapper name of device (if possible) */ +const char *device_dm_name(const struct device *device) +{ + const char *dmdir = dm_get_dir(); + size_t dmdir_len = strlen(dmdir); + + if (!device || !device->init_done) + return NULL; + + if (strncmp(device->path, dmdir, dmdir_len)) + return NULL; + + return &device->path[dmdir_len+1]; +} + +/* Get path to device / file */ +const char *device_path(const struct device *device) +{ + if (!device) + return NULL; + + if (device->file_path) + return device->file_path; + + return device->path; +} + +/* block device topology ioctls, introduced in 2.6.32 */ +#ifndef BLKIOMIN +#define BLKIOMIN _IO(0x12,120) +#define BLKIOOPT _IO(0x12,121) +#define BLKALIGNOFF _IO(0x12,122) +#endif + +void device_topology_alignment(struct crypt_device *cd, + struct device *device, + unsigned long *required_alignment, /* bytes */ + unsigned long *alignment_offset, /* bytes */ + unsigned long default_alignment) +{ + int dev_alignment_offset = 0; + unsigned int min_io_size = 0, opt_io_size = 0; + unsigned long temp_alignment = 0; + int fd; + + *required_alignment = default_alignment; + *alignment_offset = 0; + + if (!device || !device->path) //FIXME + return; + + fd = open(device->path, O_RDONLY); + if (fd == -1) + return; + + /* minimum io size */ + if (ioctl(fd, BLKIOMIN, &min_io_size) == -1) { + log_dbg(cd, "Topology info for %s not supported, using default offset %lu bytes.", + device->path, default_alignment); + goto out; + } + + /* optimal io size */ + if (ioctl(fd, BLKIOOPT, &opt_io_size) == -1) + opt_io_size = min_io_size; + + /* alignment offset, bogus -1 means misaligned/unknown */ + if (ioctl(fd, BLKALIGNOFF, &dev_alignment_offset) == -1 || dev_alignment_offset < 0) + dev_alignment_offset = 0; + *alignment_offset = (unsigned long)dev_alignment_offset; + + temp_alignment = (unsigned long)min_io_size; + + /* Ignore bogus opt-io that could break alignment */ + if ((temp_alignment < (unsigned long)opt_io_size) && + !((unsigned long)opt_io_size % temp_alignment)) + temp_alignment = (unsigned long)opt_io_size; + + /* If calculated alignment is multiple of default, keep default */ + if (temp_alignment && (default_alignment % temp_alignment)) + *required_alignment = temp_alignment; + + log_dbg(cd, "Topology: IO (%u/%u), offset = %lu; Required alignment is %lu bytes.", + min_io_size, opt_io_size, *alignment_offset, *required_alignment); +out: + (void)close(fd); +} + +size_t device_block_size(struct crypt_device *cd, struct device *device) +{ + int fd; + + if (!device) + return 0; + + if (device->block_size) + return device->block_size; + + fd = open(device->file_path ?: device->path, O_RDONLY); + if (fd >= 0) { + device->block_size = device_block_size_fd(fd, NULL); + close(fd); + } + + if (!device->block_size) + log_dbg(cd, "Cannot get block size for device %s.", device_path(device)); + + return device->block_size; +} + +int device_read_ahead(struct device *device, uint32_t *read_ahead) +{ + int fd, r = 0; + long read_ahead_long; + + if (!device) + return 0; + + if ((fd = open(device->path, O_RDONLY)) < 0) + return 0; + + r = ioctl(fd, BLKRAGET, &read_ahead_long) ? 0 : 1; + close(fd); + + if (r) + *read_ahead = (uint32_t) read_ahead_long; + + return r; +} + +/* Get data size in bytes */ +int device_size(struct device *device, uint64_t *size) +{ + struct stat st; + int devfd, r = -EINVAL; + + devfd = open(device->path, O_RDONLY); + if(devfd == -1) + return -EINVAL; + + if (fstat(devfd, &st) < 0) + goto out; + + if (S_ISREG(st.st_mode)) { + *size = (uint64_t)st.st_size; + r = 0; + } else if (ioctl(devfd, BLKGETSIZE64, size) >= 0) + r = 0; +out: + close(devfd); + return r; +} + +/* For a file, allocate the required space */ +int device_fallocate(struct device *device, uint64_t size) +{ + struct stat st; + int devfd, r = -EINVAL; + + devfd = open(device_path(device), O_RDWR); + if (devfd == -1) + return -EINVAL; + + if (!fstat(devfd, &st) && S_ISREG(st.st_mode) && + ((uint64_t)st.st_size >= size || !posix_fallocate(devfd, 0, size))) { + r = 0; + if (device->file_path && crypt_loop_resize(device->path)) + r = -EINVAL; + } + + close(devfd); + return r; +} + +int device_check_size(struct crypt_device *cd, + struct device *device, + uint64_t req_offset, int falloc) +{ + uint64_t dev_size; + + if (device_size(device, &dev_size)) { + log_dbg(cd, "Cannot get device size for device %s.", device_path(device)); + return -EIO; + } + + log_dbg(cd, "Device size %" PRIu64 ", offset %" PRIu64 ".", dev_size, req_offset); + + if (req_offset > dev_size) { + /* If it is header file, increase its size */ + if (falloc && !device_fallocate(device, req_offset)) + return 0; + + log_err(cd, _("Device %s is too small. Need at least %" PRIu64 " bytes."), + device_path(device), req_offset); + return -EINVAL; + } + + return 0; +} + +static int device_info(struct crypt_device *cd, + struct device *device, + enum devcheck device_check, + int *readonly, uint64_t *size) +{ + struct stat st; + int fd = -1, r, flags = 0, real_readonly; + uint64_t real_size; + + if (!device) + return -ENOTBLK; + + real_readonly = 0; + real_size = 0; + + if (stat(device->path, &st) < 0) { + r = -EINVAL; + goto out; + } + + /* never wipe header on mounted device */ + if (device_check == DEV_EXCL && S_ISBLK(st.st_mode)) + flags |= O_EXCL; + + /* Try to open read-write to check whether it is a read-only device */ + /* coverity[toctou] */ + fd = open(device->path, O_RDWR | flags); + if (fd == -1 && errno == EROFS) { + real_readonly = 1; + fd = open(device->path, O_RDONLY | flags); + } + + if (fd == -1 && device_check == DEV_EXCL && errno == EBUSY) { + r = -EBUSY; + goto out; + } + + if (fd == -1) { + r = errno ? -errno : -EINVAL; + goto out; + } + + r = 0; + if (S_ISREG(st.st_mode)) { + //FIXME: add readonly check + real_size = (uint64_t)st.st_size; + real_size >>= SECTOR_SHIFT; + } else { + /* If the device can be opened read-write, i.e. readonly is still 0, then + * check whether BKROGET says that it is read-only. E.g. read-only loop + * devices may be opened read-write but are read-only according to BLKROGET + */ + if (real_readonly == 0 && (r = ioctl(fd, BLKROGET, &real_readonly)) < 0) + goto out; + + r = ioctl(fd, BLKGETSIZE64, &real_size); + if (r >= 0) { + real_size >>= SECTOR_SHIFT; + goto out; + } + } +out: + if (fd != -1) + close(fd); + + switch (r) { + case 0: + if (readonly) + *readonly = real_readonly; + if (size) + *size = real_size; + break; + case -EBUSY: + log_err(cd, _("Cannot use device %s which is in use " + "(already mapped or mounted)."), device_path(device)); + break; + case -EACCES: + log_err(cd, _("Cannot use device %s, permission denied."), device_path(device)); + break; + default: + log_err(cd, _("Cannot get info about device %s."), device_path(device)); + r = -EINVAL; + } + + return r; +} + +int device_check_access(struct crypt_device *cd, + struct device *device, + enum devcheck device_check) +{ + return device_info(cd, device, device_check, NULL, NULL); +} + +static int device_internal_prepare(struct crypt_device *cd, struct device *device) +{ + char *loop_device = NULL, *file_path = NULL; + int r, loop_fd, readonly = 0; + + if (device->init_done) + return 0; + + if (getuid() || geteuid()) { + log_err(cd, _("Cannot use a loopback device, " + "running as non-root user.")); + return -ENOTSUP; + } + + log_dbg(cd, "Allocating a free loop device."); + + /* Keep the loop open, dettached on last close. */ + loop_fd = crypt_loop_attach(&loop_device, device->path, 0, 1, &readonly); + if (loop_fd == -1) { + log_err(cd, _("Attaching loopback device failed " + "(loop device with autoclear flag is required).")); + free(loop_device); + return -EINVAL; + } + + file_path = device->path; + device->path = loop_device; + + r = device_ready(cd, device); + if (r < 0) { + device->path = file_path; + crypt_loop_detach(loop_device); + free(loop_device); + return r; + } + + device->loop_fd = loop_fd; + device->file_path = file_path; + device->init_done = 1; + + return 0; +} + +int device_block_adjust(struct crypt_device *cd, + struct device *device, + enum devcheck device_check, + uint64_t device_offset, + uint64_t *size, + uint32_t *flags) +{ + int r, real_readonly; + uint64_t real_size; + + if (!device) + return -ENOTBLK; + + r = device_internal_prepare(cd, device); + if (r) + return r; + + r = device_info(cd, device, device_check, &real_readonly, &real_size); + if (r) + return r; + + if (device_offset >= real_size) { + log_err(cd, _("Requested offset is beyond real size of device %s."), + device_path(device)); + return -EINVAL; + } + + if (size && !*size) { + *size = real_size; + if (!*size) { + log_err(cd, _("Device %s has zero size."), device_path(device)); + return -ENOTBLK; + } + *size -= device_offset; + } + + /* in case of size is set by parameter */ + if (size && ((real_size - device_offset) < *size)) { + log_dbg(cd, "Device %s: offset = %" PRIu64 " requested size = %" PRIu64 + ", backing device size = %" PRIu64, + device->path, device_offset, *size, real_size); + log_err(cd, _("Device %s is too small."), device_path(device)); + return -EINVAL; + } + + if (flags && real_readonly) + *flags |= CRYPT_ACTIVATE_READONLY; + + if (size) + log_dbg(cd, "Calculated device size is %" PRIu64" sectors (%s), offset %" PRIu64 ".", + *size, real_readonly ? "RO" : "RW", device_offset); + return 0; +} + +size_t size_round_up(size_t size, size_t block) +{ + size_t s = (size + (block - 1)) / block; + return s * block; +} + +void device_disable_direct_io(struct device *device) +{ + device->o_direct = 0; +} + +int device_direct_io(const struct device *device) +{ + return device->o_direct; +} + +static dev_t device_devno(const struct device *device) +{ + struct stat st; + + if (stat(device->path, &st) || !S_ISBLK(st.st_mode)) + return 0; + + return st.st_rdev; +} + +int device_is_identical(struct device *device1, struct device *device2) +{ + if (!device1 || !device2) + return 0; + + if (device1 == device2) + return 1; + + if (device1->init_done && device2->init_done) + return (device_devno(device1) == device_devno(device2)); + else if (device1->init_done || device2->init_done) + return 0; + + if (!strcmp(device_path(device1), device_path(device2))) + return 1; + + return 0; +} + +int device_is_rotational(struct device *device) +{ + struct stat st; + + if (stat(device_path(device), &st) < 0) + return -EINVAL; + + if (!S_ISBLK(st.st_mode)) + return 0; + + return crypt_dev_is_rotational(major(st.st_rdev), minor(st.st_rdev)); +} + +size_t device_alignment(struct device *device) +{ + int devfd; + + if (!device->alignment) { + devfd = open(device_path(device), O_RDONLY); + if (devfd != -1) { + device->alignment = device_alignment_fd(devfd); + close(devfd); + } + } + + return device->alignment; +} + +int device_read_lock(struct crypt_device *cd, struct device *device) +{ + if (!crypt_metadata_locking_enabled()) + return 0; + + assert(!device_locked(device->lh)); + + device->lh = device_read_lock_handle(cd, device_path(device)); + + if (device_locked(device->lh)) { + log_dbg(cd, "Device %s READ lock taken.", device_path(device)); + return 0; + } + + return -EBUSY; +} + +int device_write_lock(struct crypt_device *cd, struct device *device) +{ + if (!crypt_metadata_locking_enabled()) + return 0; + + assert(!device_locked(device->lh)); + + device->lh = device_write_lock_handle(cd, device_path(device)); + + if (device_locked(device->lh)) { + log_dbg(cd, "Device %s WRITE lock taken.", device_path(device)); + return 0; + } + + return -EBUSY; +} + +void device_read_unlock(struct crypt_device *cd, struct device *device) +{ + if (!crypt_metadata_locking_enabled()) + return; + + assert(device_locked(device->lh) && device_locked_readonly(device->lh)); + + device_unlock_handle(cd, device->lh); + + log_dbg(cd, "Device %s READ lock released.", device_path(device)); + + device->lh = NULL; +} + +void device_write_unlock(struct crypt_device *cd, struct device *device) +{ + if (!crypt_metadata_locking_enabled()) + return; + + assert(device_locked(device->lh) && !device_locked_readonly(device->lh)); + + device_unlock_handle(cd, device->lh); + + log_dbg(cd, "Device %s WRITE lock released.", device_path(device)); + + device->lh = NULL; +} |