Re: [PATCH v5 3/8] proc: Use lsmids instead of lsm names for attrs

[Paul Moore]

On Mon, Jan 9, 2023 at 1:09 PM Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>
> Use the LSM ID number instead of the LSM name to identify which
> security module's attibute data should be shown in /proc/self/attr.
> The security_[gs]etprocattr() functions have been changed to expect
> the LSM ID. The change from a string comparison to an integer comparison
> in these functions will provide a minor performance improvement.
>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> Cc: linux-fsdevel@xxxxxxxxxxxxxxx
> ---
>  fs/proc/base.c           | 29 +++++++++++++++--------------
>  fs/proc/internal.h       |  2 +-
>  include/linux/security.h | 11 +++++------
>  security/security.c      | 11 +++++------
>  4 files changed, 26 insertions(+), 27 deletions(-)

...

> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 9e479d7d202b..9328b6b07dfc 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2837,27 +2838,27 @@ static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
>
>  #ifdef CONFIG_SECURITY_SMACK
>  static const struct pid_entry smack_attr_dir_stuff[] = {
> -       ATTR("smack", "current",        0666),
> +       ATTR(LSM_ID_SMACK, "current",   0666),
>  };
>  LSM_DIR_OPS(smack);
>  #endif
>
>  #ifdef CONFIG_SECURITY_APPARMOR
>  static const struct pid_entry apparmor_attr_dir_stuff[] = {
> -       ATTR("apparmor", "current",     0666),
> -       ATTR("apparmor", "prev",        0444),
> -       ATTR("apparmor", "exec",        0666),
> +       ATTR(LSM_ID_APPARMOR, "current",        0666),
> +       ATTR(LSM_ID_APPARMOR, "prev",           0444),
> +       ATTR(LSM_ID_APPARMOR, "exec",           0666),
>  };
>  LSM_DIR_OPS(apparmor);
>  #endif
>
>  static const struct pid_entry attr_dir_stuff[] = {
> -       ATTR(NULL, "current",           0666),
> -       ATTR(NULL, "prev",              0444),
> -       ATTR(NULL, "exec",              0666),
> -       ATTR(NULL, "fscreate",          0666),
> -       ATTR(NULL, "keycreate",         0666),
> -       ATTR(NULL, "sockcreate",        0666),
> +       ATTR(0, "current",      0666),
> +       ATTR(0, "prev",         0444),
> +       ATTR(0, "exec",         0666),
> +       ATTR(0, "fscreate",     0666),
> +       ATTR(0, "keycreate",    0666),
> +       ATTR(0, "sockcreate",   0666),

See the discussion in patch 1/8, we should use a macro instead of a 0
here (although the exact macro definition is very much up for
discussion):

  ATTR(LSM_ID_UNDEF, "current", 0666),

--
paul-moore.com