Re: [PATCH] ls: with -Z, show SMACK context for each file (v3)

[Jarkko Sakkinen]

If you still find some blocking issues, please report me, and I will 
iterate. In general I think this now much better form to achieve
support for multiple LSMs and easier to extend in future if needed.

/Jarkko

On Mon, Jun 3, 2013, at 20:05, Jarkko Sakkinen wrote:
> Enable showing of file SMACK labels with -Z command-line switch.
> 
> * src/ls.c (gobble_file): Output the smack context if available.
> * src/ls.c: New function getsmackcon_cache() for grabbing SMACK label.
> ---
>  src/local.mk |  1 +
>  src/ls.c     | 74
>  ++++++++++++++++++++++++++++++++++++++++++++----------------
>  2 files changed, 55 insertions(+), 20 deletions(-)
> 
> diff --git a/src/local.mk b/src/local.mk
> index efb0038..626d580 100644
> --- a/src/local.mk
> +++ b/src/local.mk
> @@ -230,6 +230,7 @@ src_ginstall_LDADD += $(LIB_SELINUX)
>  src_id_LDADD += $(LIB_SELINUX)
>  src_id_LDADD += $(LIB_SMACK)
>  src_ls_LDADD += $(LIB_SELINUX)
> +src_ls_LDADD += $(LIB_SMACK)
>  src_mkdir_LDADD += $(LIB_SELINUX)
>  src_mkfifo_LDADD += $(LIB_SELINUX)
>  src_mknod_LDADD += $(LIB_SELINUX)
> diff --git a/src/ls.c b/src/ls.c
> index 72aee99..24e4860 100644
> --- a/src/ls.c
> +++ b/src/ls.c
> @@ -115,6 +115,11 @@
>  # include <sys/capability.h>
>  #endif
>  
> +#ifdef HAVE_SMACK
> +# include <sys/smack.h>
> +# include <attr/xattr.h>
> +#endif
> +
>  #define PROGRAM_NAME (ls_mode == LS_LS ? "ls" \
>                        : (ls_mode == LS_MULTI_COL \
>                           ? "dir" : "vdir"))
> @@ -350,7 +355,16 @@ static struct pending *pending_dirs;
>  
>  static struct timespec current_time;
>  
> -static bool print_scontext;
> +enum scontext_type
> +  {
> +  no_context = 0,
> +  selinux_context,
> +#ifdef HAVE_SMACK
> +  smack_context,
> +#endif
> +  };
> +
> +static enum scontext_type print_scontext;
>  static char UNKNOWN_SECURITY_CONTEXT[] = "?";
>  
>  /* Whether any of the files has an ACL.  This affects the width of the
> @@ -1371,7 +1385,7 @@ main (int argc, char **argv)
>  
>    format_needs_stat = sort_type == sort_time || sort_type == sort_size
>      || format == long_format
> -    || print_scontext
> +    || print_scontext != no_context
>      || print_block_size;
>    format_needs_type = (! format_needs_stat
>                         && (recursive
> @@ -1573,7 +1587,7 @@ decode_switches (int argc, char **argv)
>    ignore_mode = IGNORE_DEFAULT;
>    ignore_patterns = NULL;
>    hide_patterns = NULL;
> -  print_scontext = false;
> +  print_scontext = no_context;
>  
>    /* FIXME: put this in a function.  */
>    {
> @@ -1949,7 +1963,11 @@ decode_switches (int argc, char **argv)
>            break;
>  
>          case 'Z':
> -          print_scontext = true;
> +          print_scontext = selinux_context;
> +#ifdef HAVE_SMACK
> +          if (smack_smackfs_path ())
> +            print_scontext = smack_context;
> +#endif
>            break;
>  
>          case_GETOPT_HELP_CHAR;
> @@ -2801,25 +2819,37 @@ errno_unsupported (int err)
>     Like getfilecon/lgetfilecon, but when F's st_dev says it's on a
>     known-
>     SELinux-challenged file system, fail with ENOTSUP immediately.  */
>  static int
> -getfilecon_cache (char const *file, struct fileinfo *f, bool deref)
> +getfilecon_cache (char const *file, struct fileinfo *f, bool deref,
> +                  enum scontext_type scontext)
>  {
>    /* st_dev of the most recently processed device for which we've
>       found that [l]getfilecon fails indicating lack of support.  */
>    static dev_t unsupported_device;
>  
> -  if (f->stat.st_dev == unsupported_device)
> +  if (f->stat.st_dev == unsupported_device || scontext == no_context)
> +    {
> +      errno = ENOTSUP;
> +      return -1;
> +    }
> +  int r = 0;
> +  if (scontext == selinux_context)
> +    r = (deref
> +         ? getfilecon (file, &f->scontext)
> +         : lgetfilecon (file, &f->scontext));
> +  else if (scontext == smack_context)
> +    r = smack_new_label_from_path (file, "security.SMACK64", deref,
> +                                   &f->scontext);
> +  else
>      {
>        errno = ENOTSUP;
>        return -1;
>      }
> -  int r = (deref
> -           ? getfilecon (file, &f->scontext)
> -           : lgetfilecon (file, &f->scontext));
>    if (r < 0 && errno_unsupported (errno))
>      unsupported_device = f->stat.st_dev;
>    return r;
>  }
>  
> +
>  /* Cache file_has_acl failure, when it's trivial to do.
>     Like file_has_acl, but when F's st_dev says it's on a file
>     system lacking ACL support, return 0 with ENOTSUP immediately.  */
> @@ -3003,15 +3033,19 @@ gobble_file (char const *name, enum filetype
> type, ino_t inode,
>            && print_with_color && is_colored (C_CAP))
>          f->has_capability = has_capability_cache (absolute_name, f);
>  
> -      if (format == long_format || print_scontext)
> +      if (format == long_format || print_scontext != no_context)
>          {
> -          bool have_selinux = false;
> +          bool have_context = false;
>            bool have_acl = false;
> -          int attr_len = getfilecon_cache (absolute_name, f, do_deref);
> +          int attr_len = getfilecon_cache (absolute_name, f, do_deref,
> +                                           print_scontext);
>            err = (attr_len < 0);
>  
>            if (err == 0)
> -            have_selinux = ! STREQ ("unlabeled", f->scontext);
> +            if (print_scontext == selinux_context)
> +              have_context = ! STREQ ("unlabeled", f->scontext);
> +            else if (print_scontext == smack_context)
> +              have_context = ! STREQ ("_", f->scontext);
>            else
>              {
>                f->scontext = UNKNOWN_SECURITY_CONTEXT;
> @@ -3031,9 +3065,9 @@ gobble_file (char const *name, enum filetype type,
> ino_t inode,
>                have_acl = (0 < n);
>              }
>  
> -          f->acl_type = (!have_selinux && !have_acl
> +          f->acl_type = (!have_context && !have_acl
>                           ? ACL_T_NONE
> -                         : (have_selinux && !have_acl
> +                         : (have_context && !have_acl
>                              ? ACL_T_SELINUX_ONLY
>                              : ACL_T_YES));
>            any_has_acl |= f->acl_type != ACL_T_NONE;
> @@ -3119,7 +3153,7 @@ gobble_file (char const *name, enum filetype type,
> ino_t inode,
>              }
>          }
>  
> -      if (print_scontext)
> +      if (print_scontext != no_context)
>          {
>            int len = strlen (f->scontext);
>            if (scontext_width < len)
> @@ -3854,7 +3888,7 @@ print_long_format (const struct fileinfo *f)
>  
>    DIRED_INDENT ();
>  
> -  if (print_owner || print_group || print_author || print_scontext)
> +  if (print_owner || print_group || print_author || print_scontext !=
> no_context)
>      {
>        DIRED_FPUTS (buf, stdout, p - buf);
>  
> @@ -3867,7 +3901,7 @@ print_long_format (const struct fileinfo *f)
>        if (print_author)
>          format_user (f->stat.st_author, author_width, f->stat_ok);
>  
> -      if (print_scontext)
> +      if (print_scontext != no_context)
>          format_user_or_group (f->scontext, 0, scontext_width);
>  
>        p = buf;
> @@ -4215,7 +4249,7 @@ print_file_name_and_frills (const struct fileinfo
> *f, size_t start_col)
>              : human_readable (ST_NBLOCKS (f->stat), buf,
>              human_output_opts,
>                                ST_NBLOCKSIZE, output_block_size));
>  
> -  if (print_scontext)
> +  if (print_scontext != no_context)
>      printf ("%*s ", format == with_commas ? 0 : scontext_width,
>      f->scontext);
>  
>    size_t width = print_name_with_quoting (f, false, NULL, start_col);
> @@ -4425,7 +4459,7 @@ length_of_file_name_and_frills (const struct
> fileinfo *f)
>                                              output_block_size))
>                  : block_size_width);
>  
> -  if (print_scontext)
> +  if (print_scontext != no_context)
>      len += 1 + (format == with_commas ? strlen (f->scontext) :
>      scontext_width);
>  
>    quote_name (NULL, f->name, filename_quoting_options, &name_width);
> -- 
> 1.8.1.2
>