Re: [Libguestfs] [libguestfs-common PATCH 2/2] options: decrypt LUKS-on-LV devices

Using the previously extracted function decrypt_mountables(), look for LUKS devices on logical volumes (LVs) too. In the LVM-on-LUKS scheme, the names of the plaintext (decrypted) block devices don't matter, as these devices host Physical Volumes, and LVM enumerates PVs automatically -- there are no references to these decrypted block devices in "/etc/fstab", for example. For naming such decrypted devices, continue calling make_mapname(). In the LUKS-on-LVM scheme however, the decrypted devices are supposed to hold filesystems, and "/etc/fstab" may refer to them. Such decrypted devices are commonly called /dev/mapper/luks-<UUID>, where <UUID> is the UUID inside the LUKS header. Employ this naming when decrypting Logical Volumes. Reuse make_mapname() as a fallback in this case. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1658126 Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1658126 Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- options/decrypt.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/options/decrypt.c b/options/decrypt.c index 9141cf5193ad..f7c1d876b3ed 100644 --- a/options/decrypt.c +++ b/options/decrypt.c @@ -38,8 +38,11 @@ #include "options.h" /** - * Make a LUKS map name from the partition name, - * eg. C<"/dev/vda2" =E<gt> "cryptvda2"> + * Make a LUKS map name from the partition or logical volume name, eg. + * C<"/dev/vda2" =E<gt> "cryptvda2">, or C<"/dev/vg-ssd/lv-root7" =E<gt> + * "cryptvgssdlvroot7">. Note that, in logical volume device names, + * c_isalnum() eliminates the "/" separator from between the VG and the LV, so + * this mapping is not unique; but for our purposes, it will do. */ static void make_mapname (const char *device, char *mapname, size_t len) @@ -67,7 +70,7 @@ make_mapname (const char *device, char *mapname, size_t len) static bool decrypt_mountables (guestfs_h *g, const char * const *mountables, - struct key_store *ks) + struct key_store *ks, bool name_decrypted_by_uuid) { bool decrypted_some = false; const char * const *mnt_scan = mountables; @@ -77,7 +80,7 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables, CLEANUP_FREE char *type = NULL; CLEANUP_FREE char *uuid = NULL; CLEANUP_FREE_STRING_LIST char **keys = NULL; - char mapname[32]; + char mapname[512]; const char * const *key_scan; const char *key; @@ -102,7 +105,9 @@ decrypt_mountables (guestfs_h *g, const char * const *mountables, assert (keys[0] != NULL); /* Generate a node name for the plaintext (decrypted) device node. */ - make_mapname (mountable, mapname, sizeof mapname); + if (!name_decrypted_by_uuid || uuid == NULL || + snprintf (mapname, sizeof mapname, "luks-%s", uuid) < 0) + make_mapname (mountable, mapname, sizeof mapname);

/* Try each key in turn. */ key_scan = (const char * const *)keys; @@ -145,15 +150,22 @@ void inspect_do_decrypt (guestfs_h *g, struct key_store *ks) { CLEANUP_FREE_STRING_LIST char **partitions = guestfs_list_partitions (g); + CLEANUP_FREE_STRING_LIST char **lvs = NULL; bool need_rescan; if (partitions == NULL) exit (EXIT_FAILURE); - need_rescan = decrypt_mountables (g, (const char * const *)partitions, ks); + need_rescan = decrypt_mountables (g, (const char * const *)partitions, ks, + false); if (need_rescan) { if (guestfs_lvm_scan (g, 1) == -1) exit (EXIT_FAILURE); } + + lvs = guestfs_lvs (g); + if (lvs == NULL) + exit (EXIT_FAILURE); + decrypt_mountables (g, (const char * const *)lvs, ks, true);