On Tue, Dec 17, 2019 at 02:01:19PM -0800, Casey Schaufler wrote:
> On 12/17/2019 9:34 AM, Stephen Smalley wrote:
> > On 12/16/19 5:35 PM, Casey Schaufler wrote:
> >> Change the secid parameter of security_audit_rule_match
> >> to a lsmblob structure pointer. Pass the entry from the
> >> lsmblob structure for the approprite slot to the LSM hook.
> >>
> >> Change the users of security_audit_rule_match to use the
> >> lsmblob instead of a u32. In some cases this requires a
> >> temporary conversion using lsmblob_init() that will go
> >> away when other interfaces get converted.
> >>
> >> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> >> Reviewed-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
> >> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> >> ---
> >> include/linux/security.h | 7 ++++---
> >> kernel/auditfilter.c | 7 +++++--
> >> kernel/auditsc.c | 14 ++++++++++----
> >> security/integrity/ima/ima.h | 4 ++--
> >> security/integrity/ima/ima_policy.c | 7 +++++--
> >> security/security.c | 18 +++++++++++++++---
> >> 6 files changed, 41 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/include/linux/security.h b/include/linux/security.h
> >> index b74dc70088ca..9c6dbe248eaf 100644
> >> --- a/include/linux/security.h
> >> +++ b/include/linux/security.h
> >> @@ -1837,7 +1837,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
> >> #ifdef CONFIG_SECURITY
> >> int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
> >> int security_audit_rule_known(struct audit_krule *krule);
> >> -int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
> >> +int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
> >> + void *lsmrule);
> >> void security_audit_rule_free(void *lsmrule);
> >> #else
> >> @@ -1853,8 +1854,8 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
> >> return 0;
> >> }
> >> -static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
> >> - void *lsmrule)
> >> +static inline int security_audit_rule_match(struct lsmblob *blob, u32 field,
> >> + u32 op, void *lsmrule)
> >> {
> >> return 0;
> >> }
> >> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> >> index b0126e9c0743..356db1dd276c 100644
> >> --- a/kernel/auditfilter.c
> >> +++ b/kernel/auditfilter.c
> >> @@ -1325,6 +1325,7 @@ int audit_filter(int msgtype, unsigned int listtype)
> >> struct audit_field *f = &e->rule.fields[i];
> >> pid_t pid;
> >> u32 sid;
> >> + struct lsmblob blob;
> >> switch (f->type) {
> >> case AUDIT_PID:
> >> @@ -1355,8 +1356,10 @@ int audit_filter(int msgtype, unsigned int listtype)
> >> case AUDIT_SUBJ_CLR:
> >> if (f->lsm_rule) {
> >> security_task_getsecid(current, &sid);
> >> - result = security_audit_rule_match(sid,
> >> - f->type, f->op, f->lsm_rule);
> >> + lsmblob_init(&blob, sid);
> >> + result = security_audit_rule_match(
> >> + &blob, f->type,
> >> + f->op, f->lsm_rule);
> >> }
> >> break;
> >> case AUDIT_EXE:
> >> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> >> index 4effe01ebbe2..7566e5b1c419 100644
> >> --- a/kernel/auditsc.c
> >> +++ b/kernel/auditsc.c
> >> @@ -445,6 +445,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> >> const struct cred *cred;
> >> int i, need_sid = 1;
> >> u32 sid;
> >> + struct lsmblob blob;
> >> unsigned int sessionid;
> >> cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
> >> @@ -643,7 +644,9 @@ static int audit_filter_rules(struct task_struct *tsk,
> >> security_task_getsecid(tsk, &sid);
> >> need_sid = 0;
> >> }
> >> - result = security_audit_rule_match(sid, f->type,
> >> + lsmblob_init(&blob, sid);
> >> + result = security_audit_rule_match(&blob,
> >> + f->type,
> >> f->op,
> >> f->lsm_rule);
> >> }
> >> @@ -658,15 +661,17 @@ static int audit_filter_rules(struct task_struct *tsk,
> >> if (f->lsm_rule) {
> >> /* Find files that match */
> >> if (name) {
> >> + lsmblob_init(&blob, name->osid);
> >> result = security_audit_rule_match(
> >> - name->osid,
> >> + &blob,
> >> f->type,
> >> f->op,
> >> f->lsm_rule);
> >> } else if (ctx) {
> >> list_for_each_entry(n, &ctx->names_list, list) {
> >> + lsmblob_init(&blob, n->osid);
> >> if (security_audit_rule_match(
> >> - n->osid,
> >> + &blob,
> >> f->type,
> >> f->op,
> >> f->lsm_rule)) {
> >> @@ -678,7 +683,8 @@ static int audit_filter_rules(struct task_struct *tsk,
> >> /* Find ipc objects that match */
> >> if (!ctx || ctx->type != AUDIT_IPC)
> >> break;
> >> - if (security_audit_rule_match(ctx->ipc.osid,
> >> + lsmblob_init(&blob, ctx->ipc.osid);
> >> + if (security_audit_rule_match(&blob,
> >> f->type, f->op,
> >> f->lsm_rule))
> >> ++result;
> >> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> >> index df4ca482fb53..d95b0ece7434 100644
> >> --- a/security/integrity/ima/ima.h
> >> +++ b/security/integrity/ima/ima.h
> >> @@ -381,8 +381,8 @@ static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
> >> return -EINVAL;
> >> }
> >> -static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
> >> - void *lsmrule)
> >> +static inline int security_filter_rule_match(struct lsmblob *blob, u32 field,
> >> + u32 op, void *lsmrule)
> >> {
> >> return -EINVAL;
> >> }
> >> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> >> index f19a895ad7cd..193ddd55420b 100644
> >> --- a/security/integrity/ima/ima_policy.c
> >> +++ b/security/integrity/ima/ima_policy.c
> >> @@ -414,6 +414,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> >> for (i = 0; i < MAX_LSM_RULES; i++) {
> >> int rc = 0;
> >> u32 osid;
> >> + struct lsmblob blob;
> >> if (!rule->lsm[i].rule)
> >> continue;
> >> @@ -423,7 +424,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> >> case LSM_OBJ_ROLE:
> >> case LSM_OBJ_TYPE:
> >> security_inode_getsecid(inode, &osid);
> >> - rc = security_filter_rule_match(osid,
> >> + lsmblob_init(&blob, osid);
> >> + rc = security_filter_rule_match(&blob,
> >> rule->lsm[i].type,
> >> Audit_equal,
> >> rule->lsm[i].rule);
> >> @@ -431,7 +433,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> >> case LSM_SUBJ_USER:
> >> case LSM_SUBJ_ROLE:
> >> case LSM_SUBJ_TYPE:
> >> - rc = security_filter_rule_match(secid,
> >> + lsmblob_init(&blob, secid);
> >> + rc = security_filter_rule_match(&blob,
> >> rule->lsm[i].type,
> >> Audit_equal,
> >> rule->lsm[i].rule);
> >> diff --git a/security/security.c b/security/security.c
> >> index a89634af639a..bfea9739c084 100644
> >> --- a/security/security.c
> >> +++ b/security/security.c
> >> @@ -439,7 +439,7 @@ static int lsm_append(const char *new, char **result)
> >> /*
> >> * Current index to use while initializing the lsmblob secid list.
> >> */
> >> -static int lsm_slot __initdata;
> >> +static int lsm_slot __lsm_ro_after_init;
> >> /**
> >> * security_add_hooks - Add a modules hooks to the hook lists.
> >> @@ -2412,9 +2412,21 @@ void security_audit_rule_free(void *lsmrule)
> >> call_void_hook(audit_rule_free, lsmrule);
> >> }
> >> -int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
> >> +int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
> >> + void *lsmrule)
> >> {
> >> - return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
> >> + struct security_hook_list *hp;
> >> + int rc;
> >> +
> >> + hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
> >> + if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
> >> + continue;
> >
> > Do you think we really need to retain these WARN_ON()s?
>
> Kees was especially keen on having the WARN_ON().
> I'd be fine with removing it.
It should really really never happen, so I like the WARN_ON staying.
-Kees
>
>
> > If not, then you could dispense with it now and leave lsm_slot as __initdata? Otherwise,
> > Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
> >
> >> + rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot],
> >> + field, op, lsmrule);
> >> + if (rc != 0)
> >> + return rc;
> >> + }
> >> + return 0;
> >> }
> >> #endif /* CONFIG_AUDIT */
> >>
> >
--
Kees Cook
