On 09/24/2018 05:18 PM, Kees Cook wrote:
> Booting with "lsm.debug" will report future details on how LSM ordering
> decisions are being made.
>
> Signed-off-by: Kees Cook <keesc...@chromium.org>
Reviewed-by: John Johansen <john.johan...@canonical.com>
> ---
> .../admin-guide/kernel-parameters.txt | 2 ++
> security/security.c | 18 ++++++++++++++++++
> 2 files changed, 20 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> index 9871e649ffef..32d323ee9218 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2274,6 +2274,8 @@
> ltpc= [NET]
> Format: <io>,<irq>,<dma>
>
> + lsm.debug [SECURITY] Enable LSM initialization debugging output.
> +
> machvec= [IA-64] Force the use of a particular machine-vector
> (machvec) in a generic kernel.
> Example: machvec=hpzx1_swiotlb
> diff --git a/security/security.c b/security/security.c
> index e74f46fba591..ee49b921d750 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -12,6 +12,8 @@
> * (at your option) any later version.
> */
>
> +#define pr_fmt(fmt) "LSM: " fmt
> +
> #include <linux/bpf.h>
> #include <linux/capability.h>
> #include <linux/dcache.h>
> @@ -43,11 +45,19 @@ char *lsm_names;
> static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
> CONFIG_DEFAULT_SECURITY;
>
> +static bool debug __initdata;
> +#define init_debug(...) \
> + do { \
> + if (debug) \
> + pr_info(__VA_ARGS__); \
> + } while (0)
> +
> static void __init major_lsm_init(void)
> {
> struct lsm_info *lsm;
>
> for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
> + init_debug("initializing %s\n", lsm->name);
> lsm->init();
> }
> }
> @@ -91,6 +101,14 @@ static int __init choose_lsm(char *str)
> }
> __setup("security=", choose_lsm);
>
> +/* Enable LSM order debugging. */
> +static int __init enable_debug(char *str)
> +{
> + debug = true;
> + return 1;
> +}
> +__setup("lsm.debug", enable_debug);
> +
> static bool match_last_lsm(const char *list, const char *lsm)
> {
> const char *last;
>
