fs: port ->permission() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

4 files changed, 7 insertions, 7 deletions

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index fa5ff13fa8c9..b202edc2ff65 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -265,7 +265,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 						    req_xattr_value_len);
 			continue;
 		}
-		size = vfs_getxattr_alloc(&init_user_ns, dentry, xattr->name,
+		size = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, xattr->name,
 					  &xattr_value, xattr_size, GFP_NOFS);
 		if (size == -ENOMEM) {
 			error = -ENOMEM;
@@ -274,7 +274,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 		if (size < 0)
 			continue;
 
-		user_space_size = vfs_getxattr(&init_user_ns, dentry,
+		user_space_size = vfs_getxattr(&nop_mnt_idmap, dentry,
 					       xattr->name, NULL, 0);
 		if (user_space_size != size)
 			pr_debug("file %s: xattr %s size mismatch (kernel: %d, user: %d)\n",
@@ -331,7 +331,7 @@ static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
 		return 1;
 
 	/* Do this the hard way */
-	rc = vfs_getxattr_alloc(&init_user_ns, dentry, XATTR_NAME_EVM,
+	rc = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_EVM,
 				(char **)&xattr_data, 0, GFP_NOFS);
 	if (rc <= 0) {
 		if (rc == -ENODATA)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index e5a6a3bb1209..45bcd08a9224 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -184,7 +184,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
 	/* if status is not PASS, try to check again - against -ENOMEM */
 
 	/* first need to know the sig type */
-	rc = vfs_getxattr_alloc(&init_user_ns, dentry, XATTR_NAME_EVM,
+	rc = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_EVM,
 				(char **)&xattr_data, 0, GFP_NOFS);
 	if (rc <= 0) {
 		evm_status = INTEGRITY_FAIL;
@@ -453,7 +453,7 @@ static int evm_xattr_change(struct user_namespace *mnt_userns,
 	char *xattr_data = NULL;
 	int rc = 0;
 
-	rc = vfs_getxattr_alloc(&init_user_ns, dentry, xattr_name, &xattr_data,
+	rc = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, xattr_name, &xattr_data,
 				0, GFP_NOFS);
 	if (rc < 0) {
 		rc = 1;
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index ee6f7e237f2e..734a6818a545 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -225,7 +225,7 @@ int ima_read_xattr(struct dentry *dentry,
 {
 	int ret;
 
-	ret = vfs_getxattr_alloc(&init_user_ns, dentry, XATTR_NAME_IMA,
+	ret = vfs_getxattr_alloc(&nop_mnt_idmap, dentry, XATTR_NAME_IMA,
 				 (char **)xattr_value, xattr_len, GFP_NOFS);
 	if (ret == -EOPNOTSUPP)
 		ret = 0;
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 4564faae7d67..6cd0add524cd 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -598,7 +598,7 @@ int ima_eventevmsig_init(struct ima_event_data *event_data,
 	if (!event_data->file)
 		return 0;
 
-	rc = vfs_getxattr_alloc(&init_user_ns, file_dentry(event_data->file),
+	rc = vfs_getxattr_alloc(&nop_mnt_idmap, file_dentry(event_data->file),
 				XATTR_NAME_EVM, (char **)&xattr_data, 0,
 				GFP_NOFS);
 	if (rc <= 0 || xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) {