| Message ID | 20180925001832.18322-18-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | LSM: Explict LSM ordering | expand |
On 09/24/2018 05:18 PM, Kees Cook wrote: > To provide a set of default-enabled LSMs at boot, this introduces the > new CONFIG_LSM_ENABLE. A value of "all" means all builtin LSMs are > enabled by default. Any unlisted LSMs will be implicitly disabled > (excepting those with LSM-specific CONFIGs for enabling/disabling). > > The behavior of the LSM-specific CONFIGs for SELinux are AppArmor > unchanged: the default-enabled state for those LSMs remains controlled > through their LSM-specific "enable" CONFIGs. > > Signed-off-by: Kees Cook <keescook@chromium.org> The patch is fine but I am not sure I like the behavior. I much prefer that its an explicit list and nothing is left to implicit. That is if there is a conflict between the list and the LSM-specific config the LSM is disabled. > --- > include/linux/lsm_hooks.h | 2 +- > security/Kconfig | 8 ++++++++ > security/security.c | 4 +++- > 3 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index 95798f212dbf..ab23f1bc6d77 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -2044,7 +2044,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, > struct lsm_info { > const char *name; /* Populated automatically. */ > unsigned long flags; /* Optional: flags describing LSM */ > - int *enabled; /* Optional: NULL means enabled. */ > + int *enabled; /* Optional: NULL checks CONFIG_LSM_ENABLE */ > int (*init)(void); > }; > > diff --git a/security/Kconfig b/security/Kconfig > index 27d8b2688f75..71306b046270 100644 > --- a/security/Kconfig > +++ b/security/Kconfig > @@ -276,5 +276,13 @@ config DEFAULT_SECURITY > default "apparmor" if DEFAULT_SECURITY_APPARMOR > default "" if DEFAULT_SECURITY_DAC > > +config LSM_ENABLE > + string "LSMs to enable at boot time" > + default "all" > + help > + A comma-separate list of LSMs to enable by default at boot. The > + default is "all", to enable all LSM modules at boot. Any LSMs > + not listed here will be disabled by default. > + > endmenu > > diff --git a/security/security.c b/security/security.c > index a8107d54b3d3..7ecb9879a863 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -45,6 +45,8 @@ char *lsm_names; > static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = > CONFIG_DEFAULT_SECURITY; > > +static __initconst const char * const builtin_lsm_enable = CONFIG_LSM_ENABLE; > + > static bool debug __initdata; > #define init_debug(...) \ > do { \ > @@ -182,7 +184,7 @@ static void __init parse_lsm_enable(const char *str, > static void __init prepare_lsm_enable(void) > { > /* Prepare defaults. */ > - parse_lsm_enable("all", default_enabled, true); > + parse_lsm_enable(builtin_lsm_enable, default_enabled, true); > } > > /** >
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 95798f212dbf..ab23f1bc6d77 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2044,7 +2044,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, struct lsm_info { const char *name; /* Populated automatically. */ unsigned long flags; /* Optional: flags describing LSM */ - int *enabled; /* Optional: NULL means enabled. */ + int *enabled; /* Optional: NULL checks CONFIG_LSM_ENABLE */ int (*init)(void); }; diff --git a/security/Kconfig b/security/Kconfig index 27d8b2688f75..71306b046270 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -276,5 +276,13 @@ config DEFAULT_SECURITY default "apparmor" if DEFAULT_SECURITY_APPARMOR default "" if DEFAULT_SECURITY_DAC +config LSM_ENABLE + string "LSMs to enable at boot time" + default "all" + help + A comma-separate list of LSMs to enable by default at boot. The + default is "all", to enable all LSM modules at boot. Any LSMs + not listed here will be disabled by default. + endmenu diff --git a/security/security.c b/security/security.c index a8107d54b3d3..7ecb9879a863 100644 --- a/security/security.c +++ b/security/security.c @@ -45,6 +45,8 @@ char *lsm_names; static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = CONFIG_DEFAULT_SECURITY; +static __initconst const char * const builtin_lsm_enable = CONFIG_LSM_ENABLE; + static bool debug __initdata; #define init_debug(...) \ do { \ @@ -182,7 +184,7 @@ static void __init parse_lsm_enable(const char *str, static void __init prepare_lsm_enable(void) { /* Prepare defaults. */ - parse_lsm_enable("all", default_enabled, true); + parse_lsm_enable(builtin_lsm_enable, default_enabled, true); } /**
To provide a set of default-enabled LSMs at boot, this introduces the new CONFIG_LSM_ENABLE. A value of "all" means all builtin LSMs are enabled by default. Any unlisted LSMs will be implicitly disabled (excepting those with LSM-specific CONFIGs for enabling/disabling). The behavior of the LSM-specific CONFIGs for SELinux are AppArmor unchanged: the default-enabled state for those LSMs remains controlled through their LSM-specific "enable" CONFIGs. Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/lsm_hooks.h | 2 +- security/Kconfig | 8 ++++++++ security/security.c | 4 +++- 3 files changed, 12 insertions(+), 2 deletions(-)