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Re: [Libguestfs] [PATCH] inspection: add support for systemd .mount files



On Mon, Mar 16, 2015 at 07:09:51PM +0100, Maros Zatko wrote:
> Fixes RHBZ#1113153.
> ---
>  src/inspect-fs-unix.c | 240 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 240 insertions(+)
> 
> diff --git a/src/inspect-fs-unix.c b/src/inspect-fs-unix.c
> index 2abbf24..6dfc299 100644
> --- a/src/inspect-fs-unix.c
> +++ b/src/inspect-fs-unix.c
> @@ -96,6 +96,9 @@ static char *resolve_fstab_device (guestfs_h *g, const char *spec,
>                                     Hash_table *md_map,
>                                     enum inspect_os_type os_type);
>  static int inspect_with_augeas (guestfs_h *g, struct inspect_fs *fs, const char **configfiles, int (*f) (guestfs_h *, struct inspect_fs *));
> +static int inspect_with_augeas2 (guestfs_h *g, struct inspect_fs *fs, const char **configfiles, int (*f) (guestfs_h *, struct inspect_fs *, const char *));

I think there is a case for splitting out the commit which adds
this new function.

Also, do we need a new function?  I don't see why it's needed at all -
just modify the old inspect_with_augeas so it passes the extra
parameter always, and update the call sites [in a separate commit].

> +static int check_systemd_mounts (guestfs_h *g, struct inspect_fs *fs);
> +static int check_systemd_mnt (guestfs_h *g, struct inspect_fs *fs, const char *path);

You don't need to prototype check_systemd_mnt at all - just remove
that line as it's confusing for people reading the code.

>  /* Hash structure for uuid->path lookups */
>  typedef struct md_uuid {
> @@ -582,6 +585,9 @@ guestfs_int_check_linux_root (guestfs_h *g, struct inspect_fs *fs)
>    if (check_hostname_unix (g, fs) == -1)
>      return -1;
>  
> +  if (check_systemd_mounts (g, fs) == -1)
> +    return -1;
> +
>    return 0;
>  }
>  
> @@ -981,6 +987,180 @@ check_hostname_freebsd (guestfs_h *g, struct inspect_fs *fs)
>  }
>  
>  static int
> +check_systemd_mnt (guestfs_h *g, struct inspect_fs *fs, const char *fname)
> +{
> +  CLEANUP_FREE_STRING_LIST char **entries = NULL;
> +  char **entry;
> +  char augpath[256];
> +  CLEANUP_HASH_FREE Hash_table *md_map = NULL;
> +  bool is_bsd = (fs->type == OS_TYPE_FREEBSD ||
> +                 fs->type == OS_TYPE_NETBSD ||
> +                 fs->type == OS_TYPE_OPENBSD);
> +
> +  /* Generate a map of MD device paths listed in /etc/mdadm.conf to MD device
> +   * paths in the guestfs appliance */
> +  if (map_md_devices (g, &md_map) == -1) {
> +    printf ("map_md_dev fail\n");

This printf shouldn't be here.

> +    return -1;
> +  }
> +
> +  char expr[512];
> +  snprintf (expr, sizeof expr, "/files%s", fname);

Yikes.  Don't use fixed size buffers, especially where (as seems to be
the case here) the path comes from user input.  Use:

  CLEANUP_FREE char *expr = NULL;
  ...
  expr = safe_asprintf (g, "/files%s", fname);

> +  entries = guestfs_aug_match (g, expr);
> +  if (entries == NULL) {
> +    return 0;
> +  }
> +
> +  for (entry = entries; *entry != NULL; entry++) {
> +    CLEANUP_FREE char *spec = NULL;
> +    CLEANUP_FREE char *mp = NULL;
> +    CLEANUP_FREE char *mountable = NULL;
> +    CLEANUP_FREE char *vfstype = NULL;
> +
> +    snprintf (augpath, sizeof augpath, "%s/Mount/What/value", *entry);
> +    spec = guestfs_aug_get (g, augpath);
> +    if (spec == NULL)
> +      return -1;
> +
> +    /* Ignore /dev/fd (floppy disks) (RHBZ#642929) and CD-ROM drives.
> +     *
> +     * /dev/iso9660/FREEBSD_INSTALL can be found in FreeBSDs installation
> +     * discs.
> +     */
> +    if ((STRPREFIX (spec, "/dev/fd") && c_isdigit (spec[7])) ||
> +        STREQ (spec, "/dev/floppy") ||
> +        STREQ (spec, "/dev/cdrom") ||
> +        STRPREFIX (spec, "/dev/iso9660/"))
> +      continue;
[etc]

There's a lot of common code with check_fstab here.  It's not
completely identical because the augeas queries are slightly
different, but you can parameterize those easily enough.

A nice thing would be a separate commit which first moves the common
code out from check_fstab into its own function.

> +static int
> +check_systemd_mounts (guestfs_h *g, struct inspect_fs *fs)
> +{
> +  const char *dirs[] = {"/etc/systemd/", "/lib/systemd/",
> +    "/usr/lib/systemd/", NULL};
> +  const char **dir;
> +  for (dir = dirs; *dir != NULL; dir++) {
> +    CLEANUP_FREE_STRING_LIST char **entries = NULL;
> +    char **entry;
> +
> +    entries = guestfs_find (g, *dir);

Error check?  If the command fails it will immediately segfault in the
next line, which is something that inspection code cannot be doing --
it's a DoS attack route.

> +    size_t cnt = guestfs_int_count_strings (entries);
> +
> +    CLEANUP_FREE_STRING_LIST char **filenames =
> +      safe_malloc (g, (cnt + 1) * sizeof (char *));
> +
> +    size_t idx = 0;
> +    for (entry = entries; *entry != NULL; entry++) {
> +      if (STRSUFFIX (*entry, ".mount")) {
> +        size_t entry_len = strlen(*dir) + strlen(*entry) + 1;
> +        filenames[idx] = safe_malloc (g, entry_len);
> +        snprintf (filenames[idx], entry_len, "%s%s", *dir, *entry);
> +        ++idx;
> +      }
> +    }
> +    filenames[idx] = NULL;
> +
> +    if (inspect_with_augeas2 (g, fs,
> +          (const char**) filenames, check_systemd_mnt) == -1) {
> +      return -1;
> +    }
> +  }
> +
> +  return 0;
> +}
> +
> +static int
>  check_fstab (guestfs_h *g, struct inspect_fs *fs)
>  {
>    CLEANUP_FREE_STRING_LIST char **entries = NULL;
> @@ -1705,6 +1885,66 @@ static char *make_augeas_path_expression (guestfs_h *g, const char **configfiles
>   * to 'f' the Augeas handle is closed.
>   */
>  static int
> +inspect_with_augeas2 (guestfs_h *g, struct inspect_fs *fs,
> +                     const char **configfiles,
> +                     int (*f) (guestfs_h *, struct inspect_fs *, const char *))
> +{

As discussed above, I don't believe this function is necessary.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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