| Message ID | 20230109180717.58855-3-casey@schaufler-ca.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | LSM: Three basic syscalls | expand |
On Mon, Jan 9, 2023 at 1:07 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > > As LSMs are registered add their lsm_id pointers to a table. > This will be used later for attribute reporting. > > Determine the number of possible security modules based on > their respective CONFIG options. This allows the number to be > known at build time. This allows data structures and tables > to use the constant. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > --- > include/linux/security.h | 2 ++ > security/security.c | 44 +++++++++++++++++++++++++++++++++------- > 2 files changed, 39 insertions(+), 7 deletions(-) > > diff --git a/include/linux/security.h b/include/linux/security.h > index 5b67f208f7de..33ed1860b96f 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -138,6 +138,8 @@ enum lockdown_reason { > }; > > extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1]; > +extern u32 lsm_active_cnt; > +extern struct lsm_id *lsm_idlist[]; > > /* These functions are in security/commoncap.c */ > extern int cap_capable(const struct cred *cred, struct user_namespace *ns, > diff --git a/security/security.c b/security/security.c > index 07a8fe7f92bf..a590fa98ddd6 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -28,12 +28,29 @@ > #include <linux/backing-dev.h> > #include <linux/string.h> > #include <linux/msg.h> > +#include <uapi/linux/lsm.h> > #include <net/flow.h> > > #define MAX_LSM_EVM_XATTR 2 > > -/* How many LSMs were built into the kernel? */ > -#define LSM_COUNT (__end_lsm_info - __start_lsm_info) > +/* > + * How many LSMs are built into the kernel as determined at > + * build time. Used to determine fixed array sizes. > + * The capability module is accounted for by CONFIG_SECURITY > + */ > +#define LSM_COUNT ( \ > + (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_IMA) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \ > + (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0)) > > /* > * These are descriptions of the reasons that can be passed to the > @@ -90,7 +107,7 @@ static __initdata const char *chosen_major_lsm; > static __initconst const char * const builtin_lsm_order = CONFIG_LSM; > > /* Ordered list of LSMs to initialize. */ > -static __initdata struct lsm_info **ordered_lsms; > +static __initdata struct lsm_info *ordered_lsms[LSM_COUNT + 1]; I'm guessing this 'LSM_COUNT + 1' logic is basically just copied from ordered_lsm_init() - which is okay - but can you remind me why it is 'LSM_COUNT + 1' and not just 'LSM_COUNT'? Based on the LSM_COUNT macro above it seems like LSM_COUNT should be enough, no? > static __initdata struct lsm_info *exclusive; > > static __initdata bool debug; > @@ -341,13 +358,16 @@ static void __init report_lsm_order(void) > pr_cont("\n"); > } > > +/* > + * Current index to use while initializing the lsm id list. > + */ > +u32 lsm_active_cnt __lsm_ro_after_init; > +struct lsm_id *lsm_idlist[LSM_COUNT] __lsm_ro_after_init; > + > static void __init ordered_lsm_init(void) > { > struct lsm_info **lsm; > > - ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms), > - GFP_KERNEL); > - > if (chosen_lsm_order) { > if (chosen_major_lsm) { > pr_warn("security=%s is ignored because it is superseded by lsm=%s\n", > @@ -388,7 +408,7 @@ static void __init ordered_lsm_init(void) > for (lsm = ordered_lsms; *lsm; lsm++) > initialize_lsm(*lsm); > > - kfree(ordered_lsms); > + init_debug("lsm count = %d\n", lsm_active_cnt); > } Given 86ef3c735ec8 ("LSM: Better reporting of actual LSMs at boot"), is this needed? -- paul-moore.com
On 1/11/2023 1:01 PM, Paul Moore wrote: > On Mon, Jan 9, 2023 at 1:07 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >> As LSMs are registered add their lsm_id pointers to a table. >> This will be used later for attribute reporting. >> >> Determine the number of possible security modules based on >> their respective CONFIG options. This allows the number to be >> known at build time. This allows data structures and tables >> to use the constant. >> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> >> --- >> include/linux/security.h | 2 ++ >> security/security.c | 44 +++++++++++++++++++++++++++++++++------- >> 2 files changed, 39 insertions(+), 7 deletions(-) >> >> diff --git a/include/linux/security.h b/include/linux/security.h >> index 5b67f208f7de..33ed1860b96f 100644 >> --- a/include/linux/security.h >> +++ b/include/linux/security.h >> @@ -138,6 +138,8 @@ enum lockdown_reason { >> }; >> >> extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1]; >> +extern u32 lsm_active_cnt; >> +extern struct lsm_id *lsm_idlist[]; >> >> /* These functions are in security/commoncap.c */ >> extern int cap_capable(const struct cred *cred, struct user_namespace *ns, >> diff --git a/security/security.c b/security/security.c >> index 07a8fe7f92bf..a590fa98ddd6 100644 >> --- a/security/security.c >> +++ b/security/security.c >> @@ -28,12 +28,29 @@ >> #include <linux/backing-dev.h> >> #include <linux/string.h> >> #include <linux/msg.h> >> +#include <uapi/linux/lsm.h> >> #include <net/flow.h> >> >> #define MAX_LSM_EVM_XATTR 2 >> >> -/* How many LSMs were built into the kernel? */ >> -#define LSM_COUNT (__end_lsm_info - __start_lsm_info) >> +/* >> + * How many LSMs are built into the kernel as determined at >> + * build time. Used to determine fixed array sizes. >> + * The capability module is accounted for by CONFIG_SECURITY >> + */ >> +#define LSM_COUNT ( \ >> + (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_IMA) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \ >> + (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0)) >> >> /* >> * These are descriptions of the reasons that can be passed to the >> @@ -90,7 +107,7 @@ static __initdata const char *chosen_major_lsm; >> static __initconst const char * const builtin_lsm_order = CONFIG_LSM; >> >> /* Ordered list of LSMs to initialize. */ >> -static __initdata struct lsm_info **ordered_lsms; >> +static __initdata struct lsm_info *ordered_lsms[LSM_COUNT + 1]; > I'm guessing this 'LSM_COUNT + 1' logic is basically just copied from > ordered_lsm_init() - which is okay - but can you remind me why it is > 'LSM_COUNT + 1' and not just 'LSM_COUNT'? Based on the LSM_COUNT > macro above it seems like LSM_COUNT should be enough, no? Yup. I didn't spend a lot of time investigating why the + 1. I'll look more deeply and correct if appropriate. >> static __initdata struct lsm_info *exclusive; >> >> static __initdata bool debug; >> @@ -341,13 +358,16 @@ static void __init report_lsm_order(void) >> pr_cont("\n"); >> } >> >> +/* >> + * Current index to use while initializing the lsm id list. >> + */ >> +u32 lsm_active_cnt __lsm_ro_after_init; >> +struct lsm_id *lsm_idlist[LSM_COUNT] __lsm_ro_after_init; >> + >> static void __init ordered_lsm_init(void) >> { >> struct lsm_info **lsm; >> >> - ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms), >> - GFP_KERNEL); >> - >> if (chosen_lsm_order) { >> if (chosen_major_lsm) { >> pr_warn("security=%s is ignored because it is superseded by lsm=%s\n", >> @@ -388,7 +408,7 @@ static void __init ordered_lsm_init(void) >> for (lsm = ordered_lsms; *lsm; lsm++) >> initialize_lsm(*lsm); >> >> - kfree(ordered_lsms); >> + init_debug("lsm count = %d\n", lsm_active_cnt); >> } > Given 86ef3c735ec8 ("LSM: Better reporting of actual LSMs at boot"), > is this needed? None of what comes out from lsm.debug is strictly necessary, and human or script can parse "initializing lsm=", but sometimes the number of LSMs is interesting. > > -- > paul-moore.com
On Wed, Jan 11, 2023 at 7:36 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > On 1/11/2023 1:01 PM, Paul Moore wrote: > > On Mon, Jan 9, 2023 at 1:07 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >> As LSMs are registered add their lsm_id pointers to a table. > >> This will be used later for attribute reporting. > >> > >> Determine the number of possible security modules based on > >> their respective CONFIG options. This allows the number to be > >> known at build time. This allows data structures and tables > >> to use the constant. > >> > >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > >> --- > >> include/linux/security.h | 2 ++ > >> security/security.c | 44 +++++++++++++++++++++++++++++++++------- > >> 2 files changed, 39 insertions(+), 7 deletions(-) ... > >> diff --git a/security/security.c b/security/security.c > >> index 07a8fe7f92bf..a590fa98ddd6 100644 > >> --- a/security/security.c > >> +++ b/security/security.c > >> @@ -388,7 +408,7 @@ static void __init ordered_lsm_init(void) > >> for (lsm = ordered_lsms; *lsm; lsm++) > >> initialize_lsm(*lsm); > >> > >> - kfree(ordered_lsms); > >> + init_debug("lsm count = %d\n", lsm_active_cnt); > >> } > > Given 86ef3c735ec8 ("LSM: Better reporting of actual LSMs at boot"), > > is this needed? > > None of what comes out from lsm.debug is strictly necessary, and > human or script can parse "initializing lsm=", but sometimes the > number of LSMs is interesting. I guess what I was questioning is if printing the @lsm_active_cnt variable provides any better information that what is already provided by commit 86ef3c735ec8? We currently print the enabled/active LSMs with lsm.debug, printing a count seems a bit redundant to me.
diff --git a/include/linux/security.h b/include/linux/security.h index 5b67f208f7de..33ed1860b96f 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -138,6 +138,8 @@ enum lockdown_reason { }; extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1]; +extern u32 lsm_active_cnt; +extern struct lsm_id *lsm_idlist[]; /* These functions are in security/commoncap.c */ extern int cap_capable(const struct cred *cred, struct user_namespace *ns, diff --git a/security/security.c b/security/security.c index 07a8fe7f92bf..a590fa98ddd6 100644 --- a/security/security.c +++ b/security/security.c @@ -28,12 +28,29 @@ #include <linux/backing-dev.h> #include <linux/string.h> #include <linux/msg.h> +#include <uapi/linux/lsm.h> #include <net/flow.h> #define MAX_LSM_EVM_XATTR 2 -/* How many LSMs were built into the kernel? */ -#define LSM_COUNT (__end_lsm_info - __start_lsm_info) +/* + * How many LSMs are built into the kernel as determined at + * build time. Used to determine fixed array sizes. + * The capability module is accounted for by CONFIG_SECURITY + */ +#define LSM_COUNT ( \ + (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_IMA) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \ + (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0)) /* * These are descriptions of the reasons that can be passed to the @@ -90,7 +107,7 @@ static __initdata const char *chosen_major_lsm; static __initconst const char * const builtin_lsm_order = CONFIG_LSM; /* Ordered list of LSMs to initialize. */ -static __initdata struct lsm_info **ordered_lsms; +static __initdata struct lsm_info *ordered_lsms[LSM_COUNT + 1]; static __initdata struct lsm_info *exclusive; static __initdata bool debug; @@ -341,13 +358,16 @@ static void __init report_lsm_order(void) pr_cont("\n"); } +/* + * Current index to use while initializing the lsm id list. + */ +u32 lsm_active_cnt __lsm_ro_after_init; +struct lsm_id *lsm_idlist[LSM_COUNT] __lsm_ro_after_init; + static void __init ordered_lsm_init(void) { struct lsm_info **lsm; - ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms), - GFP_KERNEL); - if (chosen_lsm_order) { if (chosen_major_lsm) { pr_warn("security=%s is ignored because it is superseded by lsm=%s\n", @@ -388,7 +408,7 @@ static void __init ordered_lsm_init(void) for (lsm = ordered_lsms; *lsm; lsm++) initialize_lsm(*lsm); - kfree(ordered_lsms); + init_debug("lsm count = %d\n", lsm_active_cnt); } int __init early_security_init(void) @@ -513,6 +533,16 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count, { int i; + /* + * A security module may call security_add_hooks() more + * than once. Landlock is one such case. + */ + if (lsm_active_cnt == 0 || lsm_idlist[lsm_active_cnt - 1] != lsmid) + lsm_idlist[lsm_active_cnt++] = lsmid; + + if (lsm_active_cnt > LSM_COUNT) + panic("%s Too many LSMs registered.\n", __func__); + for (i = 0; i < count; i++) { hooks[i].lsmid = lsmid; hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
As LSMs are registered add their lsm_id pointers to a table. This will be used later for attribute reporting. Determine the number of possible security modules based on their respective CONFIG options. This allows the number to be known at build time. This allows data structures and tables to use the constant. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/linux/security.h | 2 ++ security/security.c | 44 +++++++++++++++++++++++++++++++++------- 2 files changed, 39 insertions(+), 7 deletions(-)