This patch adds the probe_fs_envblk() function to identify the root filesystem and invoke fs_envblk_init() with the probed filesystem type and device. This checks if the feature is available and initializes the handle, fs_envblk, to access the external environment block. It avoids configurations with diskfilter or cryptodisk where filesystem blocks may be remapped or encrypted.
The probe is only invoked when grub-editenv is working on the default environment file path. This restriction ensures that probing and possible raw device access are not triggered for arbitrary user supplied paths, but only for the standard grubenv file. In that case the code checks if the filename equals DEFAULT_ENVBLK_PATH and then calls probe_fs_envblk with fs_envblk_spec. The result is stored in the global fs_envblk handle. At this stage the external environment block is only detected and recorded, and the behavior of grub-editenv is unchanged. Signed-off-by: Michael Chang <[email protected]> Reviewed-by: Neal Gompa <[email protected]> Reviewed-by: Avnish Chouhan <[email protected]> --- util/grub-editenv.c | 115 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 113 insertions(+), 2 deletions(-) diff --git a/util/grub-editenv.c b/util/grub-editenv.c index f8fa294d8..1b923bf97 100644 --- a/util/grub-editenv.c +++ b/util/grub-editenv.c @@ -23,8 +23,11 @@ #include <grub/util/misc.h> #include <grub/lib/envblk.h> #include <grub/i18n.h> -#include <grub/emu/hostfile.h> +#include <grub/emu/hostdisk.h> #include <grub/util/install.h> +#include <grub/emu/getroot.h> +#include <grub/fs.h> +#include <grub/crypto.h> #include <stdio.h> #include <unistd.h> @@ -158,7 +161,7 @@ static fs_envblk_spec_t fs_envblk_spec[] = { static fs_envblk_t fs_envblk = NULL; -static void __attribute__ ((unused)) +static void fs_envblk_init (const char *fs_name, const char *dev) { fs_envblk_spec_t *p; @@ -534,6 +537,111 @@ unset_variables (const char *name, int argc, char *argv[]) } } +static bool +is_abstraction (grub_device_t dev) +{ + if (dev == NULL || dev->disk == NULL) + return false; + + if (dev->disk->dev->id == GRUB_DISK_DEVICE_DISKFILTER_ID || + dev->disk->dev->id == GRUB_DISK_DEVICE_CRYPTODISK_ID) + return true; + + return false; +} + +static void +probe_fs_envblk (fs_envblk_spec_t *spec) +{ + char **grub_devices = NULL; + char **curdev, **curdrive; + size_t ndev = 0; + char **grub_drives = NULL; + grub_device_t grub_dev = NULL; + grub_fs_t grub_fs = NULL; + bool have_abstraction = false; + + grub_util_biosdisk_init (DEFAULT_DEVICE_MAP); + grub_init_all (); + grub_gcry_init_all (); + + grub_lvm_fini (); + grub_mdraid09_fini (); + grub_mdraid1x_fini (); + grub_diskfilter_fini (); + grub_diskfilter_init (); + grub_mdraid09_init (); + grub_mdraid1x_init (); + grub_lvm_init (); + + grub_devices = grub_guess_root_devices (DEFAULT_DIRECTORY); + + if (grub_devices == NULL || grub_devices[0] == NULL) + { + grub_util_warn (_("cannot find a device for %s (is /dev mounted?)"), DEFAULT_DIRECTORY); + goto cleanup; + } + + for (curdev = grub_devices; *curdev != NULL; curdev++, ndev++) + grub_util_pull_device (*curdev); + + grub_drives = xcalloc ((ndev + 1), sizeof (grub_drives[0])); + + for (curdev = grub_devices, curdrive = grub_drives; *curdev != NULL; curdev++, + curdrive++) + { + *curdrive = grub_util_get_grub_dev (*curdev); + if (*curdrive == NULL) + { + grub_util_warn (_("cannot find a GRUB drive for %s. Check your device.map"), + *curdev); + goto cleanup; + } + } + *curdrive = NULL; + + grub_dev = grub_device_open (grub_drives[0]); + if (grub_dev == NULL) + { + grub_util_warn (_("cannot open device %s: %s"), grub_drives[0], grub_errmsg); + grub_errno = GRUB_ERR_NONE; + goto cleanup; + } + + grub_fs = grub_fs_probe (grub_dev); + if (grub_fs == NULL) + { + grub_util_warn (_("cannot probe fs for %s: %s"), grub_drives[0], grub_errmsg); + grub_errno = GRUB_ERR_NONE; + goto cleanup; + } + + have_abstraction = is_abstraction (grub_dev); + for (curdrive = grub_drives + 1; *curdrive != NULL && have_abstraction == false; curdrive++) + { + grub_device_t dev = grub_device_open (*curdrive); + + if (dev == NULL) + continue; + have_abstraction = is_abstraction (dev); + grub_device_close (dev); + } + + if (have_abstraction == false) + fs_envblk_init (grub_fs->name, grub_devices[0]); + + cleanup: + if (grub_devices != NULL) + for (curdev = grub_devices; *curdev != NULL; curdev++) + free (*curdev); + free (grub_devices); + free (grub_drives); + grub_device_close (grub_dev); + grub_gcry_fini_all (); + grub_fini_all (); + grub_util_biosdisk_fini (); +} + int main (int argc, char *argv[]) { @@ -565,6 +673,9 @@ main (int argc, char *argv[]) command = argv[curindex++]; } + if (strcmp (filename, DEFAULT_ENVBLK_PATH) == 0) + probe_fs_envblk (fs_envblk_spec); + if (strcmp (command, "create") == 0) grub_util_create_envblk_file (filename); else if (strcmp (command, "list") == 0) -- 2.51.0 _______________________________________________ Grub-devel mailing list [email protected] https://lists.gnu.org/mailman/listinfo/grub-devel
