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.
> 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 */
>>
>
