src/shared/dissect-image.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include <stdbool.h>
   5
   6 #include "sd-id128.h"
   7
   8 #include "architecture.h"
   9 #include "gpt.h"
  10 #include "list.h"
  11 #include "loop-util.h"
  12 #include "macro.h"
  13
  14 typedef struct DissectedImage DissectedImage;
  15 typedef struct DissectedPartition DissectedPartition;
  16 typedef struct DecryptedImage DecryptedImage;
  17 typedef struct MountOptions MountOptions;
  18 typedef struct VeritySettings VeritySettings;
  19
  20 struct DissectedPartition {
  21         bool found:1;
  22         bool rw:1;
  23         bool growfs:1;
  24         int partno;                 /* -1 if there was no partition and the images contains a file system directly */
  25         Architecture architecture;  /* Intended architecture: either native, secondary or unset ARCHITECTURE_INVALID. */
  26         sd_id128_t uuid;            /* Partition entry UUID as reported by the GPT */
  27         char *fstype;
  28         char *node;
  29         char *label;
  30         char *decrypted_node;
  31         char *decrypted_fstype;
  32         char *mount_options;
  33         int mount_node_fd;
  34         uint64_t size;
  35         uint64_t offset;
  36         uint64_t gpt_flags;
  37 };
  38
  39 #define DISSECTED_PARTITION_NULL                                        \
  40         ((DissectedPartition) {                                         \
  41                 .partno = -1,                                           \
  42                 .architecture = _ARCHITECTURE_INVALID,                  \
  43                 .mount_node_fd = -EBADF,                                \
  44         })
  45 #define TAKE_PARTITION(p)                                       \
  46         ({                                                      \
  47                 DissectedPartition *_pp = &(p), _p = *_pp;      \
  48                 *_pp = DISSECTED_PARTITION_NULL;                \
  49                 _p;                                             \
  50         })
  51
  52 typedef enum DissectImageFlags {
  53         DISSECT_IMAGE_DEVICE_READ_ONLY         = 1 << 0,  /* Make device read-only */
  54         DISSECT_IMAGE_DISCARD_ON_LOOP          = 1 << 1,  /* Turn on "discard" if on a loop device and file system supports it */
  55         DISSECT_IMAGE_DISCARD                  = 1 << 2,  /* Turn on "discard" if file system supports it, on all block devices */
  56         DISSECT_IMAGE_DISCARD_ON_CRYPTO        = 1 << 3,  /* Turn on "discard" also on crypto devices */
  57         DISSECT_IMAGE_DISCARD_ANY              = DISSECT_IMAGE_DISCARD_ON_LOOP |
  58                                                  DISSECT_IMAGE_DISCARD |
  59                                                  DISSECT_IMAGE_DISCARD_ON_CRYPTO,
  60         DISSECT_IMAGE_GPT_ONLY                 = 1 << 4,  /* Only recognize images with GPT partition tables */
  61         DISSECT_IMAGE_GENERIC_ROOT             = 1 << 5,  /* If no partition table or only single generic partition, assume it's the root fs */
  62         DISSECT_IMAGE_MOUNT_ROOT_ONLY          = 1 << 6,  /* Mount only the root and /usr partitions */
  63         DISSECT_IMAGE_MOUNT_NON_ROOT_ONLY      = 1 << 7,  /* Mount only the non-root and non-/usr partitions */
  64         DISSECT_IMAGE_VALIDATE_OS              = 1 << 8,  /* Refuse mounting images that aren't identifiable as OS images */
  65         DISSECT_IMAGE_VALIDATE_OS_EXT          = 1 << 9,  /* Refuse mounting images that aren't identifiable as OS extension images */
  66         DISSECT_IMAGE_RELAX_VAR_CHECK          = 1 << 10, /* Don't insist that the UUID of /var is hashed from /etc/machine-id */
  67         DISSECT_IMAGE_FSCK                     = 1 << 11, /* File system check the partition before mounting (no effect when combined with DISSECT_IMAGE_READ_ONLY) */
  68         DISSECT_IMAGE_NO_PARTITION_TABLE       = 1 << 12, /* Only recognize single file system images */
  69         DISSECT_IMAGE_VERITY_SHARE             = 1 << 13, /* When activating a verity device, reuse existing one if already open */
  70         DISSECT_IMAGE_MKDIR                    = 1 << 14, /* Make top-level directory to mount right before mounting, if missing */
  71         DISSECT_IMAGE_USR_NO_ROOT              = 1 << 15, /* If no root fs is in the image, but /usr is, then allow this (so that we can mount the rootfs as tmpfs or so */
  72         DISSECT_IMAGE_REQUIRE_ROOT             = 1 << 16, /* Don't accept disks without root partition (or at least /usr partition if DISSECT_IMAGE_USR_NO_ROOT is set) */
  73         DISSECT_IMAGE_MOUNT_READ_ONLY          = 1 << 17, /* Make mounts read-only */
  74         DISSECT_IMAGE_READ_ONLY                = DISSECT_IMAGE_DEVICE_READ_ONLY |
  75                                                  DISSECT_IMAGE_MOUNT_READ_ONLY,
  76         DISSECT_IMAGE_GROWFS                   = 1 << 18, /* Grow file systems in partitions marked for that to the size of the partitions after mount */
  77         DISSECT_IMAGE_MOUNT_IDMAPPED           = 1 << 19, /* Mount mounts with kernel 5.12-style userns ID mapping, if file system type doesn't support uid=/gid= */
  78         DISSECT_IMAGE_ADD_PARTITION_DEVICES    = 1 << 20, /* Create partition devices via BLKPG_ADD_PARTITION */
  79         DISSECT_IMAGE_PIN_PARTITION_DEVICES    = 1 << 21, /* Open dissected partitions and decrypted partitions and pin them by fd */
  80         DISSECT_IMAGE_RELAX_SYSEXT_CHECK       = 1 << 22, /* Don't insist that the extension-release file name matches the image name */
  81 } DissectImageFlags;
  82
  83 struct DissectedImage {
  84         bool encrypted:1;
  85         bool has_verity:1;         /* verity available in image, but not necessarily used */
  86         bool has_verity_sig:1;     /* pkcs#7 signature embedded in image */
  87         bool verity_ready:1;       /* verity available, fully specified and usable */
  88         bool verity_sig_ready:1;   /* verity signature logic, fully specified and usable */
  89         bool single_file_system:1; /* MBR/GPT or single file system */
  90
  91         LoopDevice *loop;
  92         DissectedPartition partitions[_PARTITION_DESIGNATOR_MAX];
  93         DecryptedImage *decrypted_image;
  94
  95         /* Meta information extracted from /etc/os-release and similar */
  96         char *image_name;
  97         sd_id128_t image_uuid;
  98         char *hostname;
  99         sd_id128_t machine_id;
 100         char **machine_info;
 101         char **os_release;
 102         char **initrd_release;
 103         char **extension_release;
 104         int has_init_system;
 105 };
 106
 107 struct MountOptions {
 108         PartitionDesignator partition_designator;
 109         char *options;
 110         LIST_FIELDS(MountOptions, mount_options);
 111 };
 112
 113 struct VeritySettings {
 114         /* Binary root hash for the Verity Merkle tree */
 115         void *root_hash;
 116         size_t root_hash_size;
 117
 118         /* PKCS#7 signature of the above */
 119         void *root_hash_sig;
 120         size_t root_hash_sig_size;
 121
 122         /* Path to the verity data file, if stored externally */
 123         char *data_path;
 124
 125         /* PARTITION_ROOT or PARTITION_USR, depending on what these Verity settings are for */
 126         PartitionDesignator designator;
 127 };
 128
 129 #define VERITY_SETTINGS_DEFAULT {                               \
 130                 .designator = _PARTITION_DESIGNATOR_INVALID     \
 131         }
 132
 133 MountOptions* mount_options_free_all(MountOptions *options);
 134 DEFINE_TRIVIAL_CLEANUP_FUNC(MountOptions*, mount_options_free_all);
 135 const char* mount_options_from_designator(const MountOptions *options, PartitionDesignator designator);
 136
 137 int probe_filesystem_full(int fd, const char *path, uint64_t offset, uint64_t size, char **ret_fstype);
 138 static inline int probe_filesystem(const char *path, char **ret_fstype) {
 139         return probe_filesystem_full(-1, path, 0, UINT64_MAX, ret_fstype);
 140 }
 141 int dissect_image_file(
 142                 const char *path,
 143                 const VeritySettings *verity,
 144                 const MountOptions *mount_options,
 145                 DissectImageFlags flags,
 146                 DissectedImage **ret);
 147 int dissect_loop_device(LoopDevice *loop, const VeritySettings *verity, const MountOptions *mount_options, DissectImageFlags flags, DissectedImage **ret);
 148 int dissect_loop_device_and_warn(LoopDevice *loop, const VeritySettings *verity, const MountOptions *mount_options, DissectImageFlags flags, DissectedImage **ret);
 149
 150 DissectedImage* dissected_image_unref(DissectedImage *m);
 151 DEFINE_TRIVIAL_CLEANUP_FUNC(DissectedImage*, dissected_image_unref);
 152
 153 int dissected_image_decrypt(DissectedImage *m, const char *passphrase, const VeritySettings *verity, DissectImageFlags flags);
 154 int dissected_image_decrypt_interactively(DissectedImage *m, const char *passphrase, const VeritySettings *verity, DissectImageFlags flags);
 155 int dissected_image_mount(DissectedImage *m, const char *dest, uid_t uid_shift, uid_t uid_range, DissectImageFlags flags);
 156 int dissected_image_mount_and_warn(DissectedImage *m, const char *where, uid_t uid_shift, uid_t uid_range, DissectImageFlags flags);
 157
 158 int dissected_image_acquire_metadata(DissectedImage *m, DissectImageFlags extra_flags);
 159
 160 DecryptedImage* decrypted_image_ref(DecryptedImage *p);
 161 DecryptedImage* decrypted_image_unref(DecryptedImage *p);
 162 DEFINE_TRIVIAL_CLEANUP_FUNC(DecryptedImage*, decrypted_image_unref);
 163
 164 int dissected_image_relinquish(DissectedImage *m);
 165
 166 int verity_settings_load(VeritySettings *verity, const char *image, const char *root_hash_path, const char *root_hash_sig_path);
 167 void verity_settings_done(VeritySettings *verity);
 168
 169 static inline bool verity_settings_data_covers(const VeritySettings *verity, PartitionDesignator d) {
 170         /* Returns true if the verity settings contain sufficient information to cover the specified partition */
 171         return verity &&
 172                 ((d >= 0 && verity->designator == d) || (d == PARTITION_ROOT && verity->designator < 0)) &&
 173                 verity->root_hash &&
 174                 verity->data_path;
 175 }
 176
 177 int dissected_image_load_verity_sig_partition(DissectedImage *m, int fd, VeritySettings *verity);
 178
 179 bool dissected_image_verity_candidate(const DissectedImage *image, PartitionDesignator d);
 180 bool dissected_image_verity_ready(const DissectedImage *image, PartitionDesignator d);
 181 bool dissected_image_verity_sig_ready(const DissectedImage *image, PartitionDesignator d);
 182
 183 int mount_image_privately_interactively(const char *path, DissectImageFlags flags, char **ret_directory, LoopDevice **ret_loop_device);
 184
 185 int verity_dissect_and_mount(int src_fd, const char *src, const char *dest, const MountOptions *options, const char *required_host_os_release_id, const char *required_host_os_release_version_id, const char *required_host_os_release_sysext_level, const char *required_sysext_scope);