[PATCH v24 11/25] LSM: Use lsmblob in security_inode_getsecid

Casey Schaufler
2021-01-27T00:12:17Z

Change the security_inode_getsecid() interface to fill in a
lsmblob structure instead of a u32 secid. This allows for its
callers to gather data from all registered LSMs. Data is provided
for IMA and audit.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
Cc: linux-audit@redhat.com
---
include/linux/security.h | 7 ++++---
kernel/auditsc.c | 6 +++++-
security/integrity/ima/ima_policy.c | 4 +---
security/security.c | 11 +++++++++--
4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 9fc245c1f739..e8d73b0220e4 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -441,7 +441,7 @@ int security_inode_killpriv(struct dentry *dentry);
int security_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc);
int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
-void security_inode_getsecid(struct inode *inode, u32 *secid);
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob);
int security_inode_copy_up(struct dentry *src, struct cred **new);
int security_inode_copy_up_xattr(const char *name);
int security_kernfs_init_security(struct kernfs_node *kn_dir,
@@ -968,9 +968,10 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer,
return 0;
}

-static inline void security_inode_getsecid(struct inode *inode, u32 *secid)
+static inline void security_inode_getsecid(struct inode *inode,
+ struct lsmblob *blob)
{
- *secid = 0;
+ lsmblob_init(blob, 0);
}

static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 62e2e6de5486..7883b8ac8ea4 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1966,13 +1966,17 @@ static void audit_copy_inode(struct audit_names *name,
const struct dentry *dentry,
struct inode *inode, unsigned int flags)
{
+ struct lsmblob blob;
+
name->ino = inode->i_ino;
name->dev = inode->i_sb->s_dev;
name->mode = inode->i_mode;
name->uid = inode->i_uid;
name->gid = inode->i_gid;
name->rdev = inode->i_rdev;
- security_inode_getsecid(inode, &name->osid);
+ security_inode_getsecid(inode, &blob);
+ /* scaffolding until osid is updated */
+ name->osid = blob.secid[0];
if (flags & AUDIT_INODE_NOEVAL) {
name->fcap_ver = -1;
return;
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 265184921eef..ab66266fe932 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -575,7 +575,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
int rc = 0;
- u32 osid;
struct lsmblob lsmdata;

if (!ima_lsm_isset(rule, i)) {
@@ -588,8 +587,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
case LSM_OBJ_USER:
case LSM_OBJ_ROLE:
case LSM_OBJ_TYPE:
- security_inode_getsecid(inode, &osid);
- lsmblob_init(&lsmdata, osid);
+ security_inode_getsecid(inode, &lsmdata);
rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
Audit_equal,
rule->lsm[i].rules);
diff --git a/security/security.c b/security/security.c
index 3f0a3aedad19..9241245a9d4b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1489,9 +1489,16 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
}
EXPORT_SYMBOL(security_inode_listsecurity);

-void security_inode_getsecid(struct inode *inode, u32 *secid)
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob)
{
- call_void_hook(inode_getsecid, inode, secid);
+ struct security_hook_list *hp;
+
+ lsmblob_init(blob, 0);
+ hlist_for_each_entry(hp, &security_hook_heads.inode_getsecid, list) {
+ if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+ continue;
+ hp->hook.inode_getsecid(inode, &blob->secid[hp->lsmid->slot]);
+ }
}

int security_inode_copy_up(struct dentry *src, struct cred **new)
--
2.25.4