fs: port i_{g,u}id_into_vfs{g,u}id() to const mnt_idmap

Convert to const struct mnt_idmap.

A mount's idmapping is immutable. The only thing that is allowed to be
modified afterwards is the reference count and that is hidden behind
mnt_idmap_get() and mnt_idmap_put(). Everything else only ever reads
from the idmapping. This is the same model that struct cred uses and the
idmapping is also rather sensitive.

So make the idmap argument const wherever we can. The conversion is done
from the bottom up so callers can continue to pass a non-const pointer
to a const parameter until the conversion is finished.

No functional changes.

Link: https://patch.msgid.link/20260901-work-idmap-const-v1-5-54ccd48e100b@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Seth Forshee <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

5 files changed, 10 insertions, 10 deletions

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 10214f73ca1e..b502854f28ee 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -423,7 +423,7 @@ static inline void ima_process_queued_keys(void) {}
 #endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */
 
 /* LIM API function definitions */
-int ima_get_action(struct mnt_idmap *idmap, struct inode *inode,
+int ima_get_action(const struct mnt_idmap *idmap, struct inode *inode,
 		   const struct cred *cred, struct lsm_prop *prop, int mask,
 		   enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
@@ -437,7 +437,7 @@ void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
 			   struct evm_ima_xattr_data *xattr_value,
 			   int xattr_len, const struct modsig *modsig, int pcr,
 			   struct ima_template_desc *template_desc);
-int process_buffer_measurement(struct mnt_idmap *idmap,
+int process_buffer_measurement(const struct mnt_idmap *idmap,
 			       struct inode *inode, const void *buf, int size,
 			       const char *eventname, enum ima_hooks func,
 			       int pcr, const char *func_data,
@@ -454,7 +454,7 @@ void ima_free_template_entry(struct ima_template_entry *entry);
 const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
 
 /* IMA policy related functions */
-int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
+int ima_match_policy(const struct mnt_idmap *idmap, struct inode *inode,
 		     const struct cred *cred, struct lsm_prop *prop,
 		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,
@@ -489,7 +489,7 @@ int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
 			     struct evm_ima_xattr_data *xattr_value,
 			     int xattr_len, const struct modsig *modsig,
 			     bool bprm_is_check);
-int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode,
+int ima_must_appraise(const struct mnt_idmap *idmap, struct inode *inode,
 		      int mask, enum ima_hooks func);
 void ima_update_xattr(struct ima_iint_cache *iint, struct file *file);
 enum integrity_status ima_get_cache_status(struct ima_iint_cache *iint,
@@ -519,7 +519,7 @@ static inline int ima_appraise_measurement(enum ima_hooks func,
 	return INTEGRITY_UNKNOWN;
 }
 
-static inline int ima_must_appraise(struct mnt_idmap *idmap,
+static inline int ima_must_appraise(const struct mnt_idmap *idmap,
 				    struct inode *inode, int mask,
 				    enum ima_hooks func)
 {
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 122d127e108d..3c5a23b4a2ff 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -188,7 +188,7 @@ err_out:
  * Returns IMA_MEASURE, IMA_APPRAISE mask.
  *
  */
-int ima_get_action(struct mnt_idmap *idmap, struct inode *inode,
+int ima_get_action(const struct mnt_idmap *idmap, struct inode *inode,
 		   const struct cred *cred, struct lsm_prop *prop, int mask,
 		   enum ima_hooks func, int *pcr,
 		   struct ima_template_desc **template_desc,
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index ced2e131b061..6b21db789ef1 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -71,7 +71,7 @@ bool is_ima_appraise_enabled(void)
  *
  * Return 1 to appraise or hash
  */
-int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode,
+int ima_must_appraise(const struct mnt_idmap *idmap, struct inode *inode,
 		      int mask, enum ima_hooks func)
 {
 	struct lsm_prop prop;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index ab1e53b3210d..8d9c92dc8825 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1095,7 +1095,7 @@ static int ima_post_load_data(char *buf, loff_t size,
  * has been written to the passed location but not added to a measurement entry,
  * a negative value otherwise.
  */
-int process_buffer_measurement(struct mnt_idmap *idmap,
+int process_buffer_measurement(const struct mnt_idmap *idmap,
 			       struct inode *inode, const void *buf, int size,
 			       const char *eventname, enum ima_hooks func,
 			       int pcr, const char *func_data,
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index f79d07bb63c6..89d197d99383 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -575,7 +575,7 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule,
  * Returns true on rule match, false on failure.
  */
 static bool ima_match_rules(struct ima_rule_entry *rule,
-			    struct mnt_idmap *idmap,
+			    const struct mnt_idmap *idmap,
 			    struct inode *inode, const struct cred *cred,
 			    struct lsm_prop *prop, enum ima_hooks func, int mask,
 			    const char *func_data)
@@ -757,7 +757,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
  * list when walking it.  Reads are many orders of magnitude more numerous
  * than writes so ima_match_policy() is classical RCU candidate.
  */
-int ima_match_policy(struct mnt_idmap *idmap, struct inode *inode,
+int ima_match_policy(const struct mnt_idmap *idmap, struct inode *inode,
 		     const struct cred *cred, struct lsm_prop *prop,
 		     enum ima_hooks func, int mask, int flags, int *pcr,
 		     struct ima_template_desc **template_desc,