[PATCH v30 12/28] LSM: Use lsmblob in security_inode_getsecid

Casey Schaufler
2021-11-24T01:57:05Z

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 <stephen.smalley.work@gmail.com>
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 | 7 ++++---
security/security.c | 11 +++++++++--
4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index efd6e88d57b1..f324acc2c029 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -457,7 +457,7 @@ int security_inode_getsecurity(struct user_namespace *mnt_userns,
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,
@@ -1009,9 +1009,10 @@ 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 7cd70a43408f..3123c97d13b3 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2239,13 +2239,17 @@ 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 22952efcc0b0..34ecdd7b01f5 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -625,7 +625,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
int rc = 0;
- u32 osid;
+ struct lsmblob lsmdata;

if (!rule->lsm[i].rule) {
if (!rule->lsm[i].args_p)
@@ -637,8 +637,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
case LSM_OBJ_USER:
case LSM_OBJ_ROLE:
case LSM_OBJ_TYPE:
- security_inode_getsecid(inode, &osid);
- rc = ima_filter_rule_match(osid, rule->lsm[i].type,
+ security_inode_getsecid(inode, &lsmdata);
+ rc = ima_filter_rule_match(lsmdata.secid[rule->which],
+ rule->lsm[i].type,
Audit_equal,
rule->lsm[i].rule,
rule->which);
diff --git a/security/security.c b/security/security.c
index 1b9f33097216..54b5dbe63265 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1550,9 +1550,16 @@ 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)