[PATCH v39 11/42] LSM: Use lsmblob in security_inode_getsecid

From: Casey Schaufler
Date: Fri Dec 15 2023 - 17:24:53 EST


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. Change the name to security_inode_getlsmblob().

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
Acked-by: Stephen Smalley <stephen.smalley.work@xxxxxxxxx>
Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Cc: linux-integrity@xxxxxxxxxxxxxxx
Cc: audit@xxxxxxxxxxxxxxx
---
include/linux/lsm_hook_defs.h | 3 ++-
include/linux/security.h | 7 ++++---
kernel/auditsc.c | 6 +++++-
security/integrity/ima/ima_policy.c | 3 +--
security/security.c | 11 +++++------
security/selinux/hooks.c | 15 +++++++++------
security/smack/smack_lsm.c | 12 +++++++-----
7 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 2db7320a1e05..3c51ee8e3d6c 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -161,7 +161,8 @@ LSM_HOOK(int, -EOPNOTSUPP, inode_setsecurity, struct inode *inode,
const char *name, const void *value, size_t size, int flags)
LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer,
size_t buffer_size)
-LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid)
+LSM_HOOK(void, LSM_RET_VOID, inode_getlsmblob, struct inode *inode,
+ struct lsmblob *blob)
LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new)
LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, const char *name)
LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir,
diff --git a/include/linux/security.h b/include/linux/security.h
index 6306e8ab0cf6..e8b7f858de04 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -431,7 +431,7 @@ int security_inode_getsecurity(struct mnt_idmap *idmap,
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_getlsmblob(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,
@@ -1020,9 +1020,10 @@ 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_getlsmblob(struct inode *inode,
+ struct lsmblob *blob)
{
- *secid = 0;
+ lsmblob_init(blob);
}

static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 7afeae468745..b15e44e56409 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2276,13 +2276,17 @@ 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_getlsmblob(inode, &blob);
+ /* stacking scaffolding */
+ name->osid = blob.scaffold.secid;
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 48287b75fe77..8edf7a0ef9f6 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -671,8 +671,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
case LSM_OBJ_USER:
case LSM_OBJ_ROLE:
case LSM_OBJ_TYPE:
- /* stacking scaffolding */
- security_inode_getsecid(inode, &blob.scaffold.secid);
+ security_inode_getlsmblob(inode, &blob);
rc = ima_filter_rule_match(&blob, lsm_rule->lsm[i].type,
Audit_equal,
lsm_rule->lsm[i].rule,
diff --git a/security/security.c b/security/security.c
index 58387e1f0c04..ed4e9b5fdf70 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2607,16 +2607,15 @@ int security_inode_listsecurity(struct inode *inode,
EXPORT_SYMBOL(security_inode_listsecurity);

/**
- * security_inode_getsecid() - Get an inode's secid
+ * security_inode_getlsmblob() - Get an inode's LSM data
* @inode: inode
- * @secid: secid to return
+ * @blob: lsm specific information to return
*
- * Get the secid associated with the node. In case of failure, @secid will be
- * set to zero.
+ * Get the lsm specific information associated with the node.
*/
-void security_inode_getsecid(struct inode *inode, u32 *secid)
+void security_inode_getlsmblob(struct inode *inode, struct lsmblob *blob)
{
- call_void_hook(inode_getsecid, inode, secid);
+ call_void_hook(inode_getlsmblob, inode, blob);
}

/**
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d70000363b7a..4ab923698da9 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3496,15 +3496,18 @@ static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t
return len;
}

-static void selinux_inode_getsecid(struct inode *inode, u32 *secid)
+static void selinux_inode_getlsmblob(struct inode *inode, struct lsmblob *blob)
{
struct inode_security_struct *isec = inode_security_novalidate(inode);
- *secid = isec->sid;
+
+ blob->selinux.secid = isec->sid;
+ /* stacking scaffolding */
+ blob->scaffold.secid = isec->sid;
}

static int selinux_inode_copy_up(struct dentry *src, struct cred **new)
{
- u32 sid;
+ struct lsmblob blob;
struct task_security_struct *tsec;
struct cred *new_creds = *new;

@@ -3516,8 +3519,8 @@ static int selinux_inode_copy_up(struct dentry *src, struct cred **new)

tsec = selinux_cred(new_creds);
/* Get label from overlay inode and set it in create_sid */
- selinux_inode_getsecid(d_inode(src), &sid);
- tsec->create_sid = sid;
+ selinux_inode_getlsmblob(d_inode(src), &blob);
+ tsec->create_sid = blob.selinux.secid;
*new = new_creds;
return 0;
}
@@ -7125,7 +7128,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
LSM_HOOK_INIT(inode_getsecurity, selinux_inode_getsecurity),
LSM_HOOK_INIT(inode_setsecurity, selinux_inode_setsecurity),
LSM_HOOK_INIT(inode_listsecurity, selinux_inode_listsecurity),
- LSM_HOOK_INIT(inode_getsecid, selinux_inode_getsecid),
+ LSM_HOOK_INIT(inode_getlsmblob, selinux_inode_getlsmblob),
LSM_HOOK_INIT(inode_copy_up, selinux_inode_copy_up),
LSM_HOOK_INIT(inode_copy_up_xattr, selinux_inode_copy_up_xattr),
LSM_HOOK_INIT(path_notify, selinux_path_notify),
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 46cc79eb1200..e6d49e59a0c0 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1615,15 +1615,17 @@ static int smack_inode_listsecurity(struct inode *inode, char *buffer,
}

/**
- * smack_inode_getsecid - Extract inode's security id
+ * smack_inode_getlsmblob - Extract inode's security id
* @inode: inode to extract the info from
- * @secid: where result will be saved
+ * @blob: where result will be saved
*/
-static void smack_inode_getsecid(struct inode *inode, u32 *secid)
+static void smack_inode_getlsmblob(struct inode *inode, struct lsmblob *blob)
{
struct smack_known *skp = smk_of_inode(inode);

- *secid = skp->smk_secid;
+ blob->smack.skp = skp;
+ /* stacking scaffolding */
+ blob->scaffold.secid = skp->smk_secid;
}

/*
@@ -5081,7 +5083,7 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
LSM_HOOK_INIT(inode_getsecurity, smack_inode_getsecurity),
LSM_HOOK_INIT(inode_setsecurity, smack_inode_setsecurity),
LSM_HOOK_INIT(inode_listsecurity, smack_inode_listsecurity),
- LSM_HOOK_INIT(inode_getsecid, smack_inode_getsecid),
+ LSM_HOOK_INIT(inode_getlsmblob, smack_inode_getlsmblob),

LSM_HOOK_INIT(file_alloc_security, smack_file_alloc_security),
LSM_HOOK_INIT(file_ioctl, smack_file_ioctl),
--
2.41.0