[PATCH -next 1/2] fs: Change notify_change() to take struct path argument

From: Xiu Jianfeng
Date: Fri May 05 2023 - 04:13:42 EST

For path-based LSMs such as Landlock, struct path instead of struct
dentry is required to make sense of attr/xattr accesses. notify_change()
is the main caller of security_inode_setattr(), so refactor it first
before lsm hook inode_setattr().

This patch also touches do_truncate() and other related callers.

Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
---
drivers/base/devtmpfs.c | 5 +++--
fs/attr.c | 5 +++--
fs/cachefiles/interface.c | 4 ++--
fs/coredump.c | 2 +-
fs/ecryptfs/inode.c | 18 +++++++++---------
fs/inode.c | 8 +++++---
fs/ksmbd/smb2pdu.c | 6 +++---
fs/ksmbd/smbacl.c | 2 +-
fs/namei.c | 2 +-
fs/nfsd/vfs.c | 12 ++++++++----
fs/open.c | 19 ++++++++++---------
fs/overlayfs/overlayfs.h | 4 +++-
fs/utimes.c | 2 +-
include/linux/fs.h | 4 ++--
14 files changed, 52 insertions(+), 41 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index b848764ef018..e67dd258984c 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -220,13 +220,14 @@ static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
dev->devt);
if (!err) {
struct iattr newattrs;
+ struct path new = { .mnt = path.mnt, .dentry = dentry };

newattrs.ia_mode = mode;
newattrs.ia_uid = uid;
newattrs.ia_gid = gid;
newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
inode_lock(d_inode(dentry));
- notify_change(&nop_mnt_idmap, dentry, &newattrs, NULL);
+ notify_change(&nop_mnt_idmap, &new, &newattrs, NULL);
inode_unlock(d_inode(dentry));

/* mark as kernel-created inode */
@@ -334,7 +335,7 @@ static int handle_remove(const char *nodename, struct device *dev)
newattrs.ia_valid =
ATTR_UID|ATTR_GID|ATTR_MODE;
inode_lock(d_inode(dentry));
- notify_change(&nop_mnt_idmap, dentry, &newattrs, NULL);
+ notify_change(&nop_mnt_idmap, &p, &newattrs, NULL);
inode_unlock(d_inode(dentry));
err = vfs_unlink(&nop_mnt_idmap, d_inode(parent.dentry),
dentry, NULL);
diff --git a/fs/attr.c b/fs/attr.c
index d60dc1edb526..eecd78944b83 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -354,7 +354,7 @@ EXPORT_SYMBOL(may_setattr);
/**
* notify_change - modify attributes of a filesytem object
* @idmap: idmap of the mount the inode was found from
- * @dentry: object affected
+ * @path: path of object affected
* @attr: new attributes
* @delegated_inode: returns inode, if the inode is delegated
*
@@ -378,9 +378,10 @@ EXPORT_SYMBOL(may_setattr);
* permissions. On non-idmapped mounts or if permission checking is to be
* performed on the raw inode simply pass @nop_mnt_idmap.
*/
-int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
+int notify_change(struct mnt_idmap *idmap, const struct path *path,
struct iattr *attr, struct inode **delegated_inode)
{
+ struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
umode_t mode = inode->i_mode;
int error;
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index 40052bdb3365..4700285a76f0 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -138,7 +138,7 @@ static int cachefiles_adjust_size(struct cachefiles_object *object)
newattrs.ia_size = oi_size & PAGE_MASK;
ret = cachefiles_inject_remove_error();
if (ret == 0)
- ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
+ ret = notify_change(&nop_mnt_idmap, &file->f_path,
&newattrs, NULL);
if (ret < 0)
goto truncate_failed;
@@ -148,7 +148,7 @@ static int cachefiles_adjust_size(struct cachefiles_object *object)
newattrs.ia_size = ni_size;
ret = cachefiles_inject_write_error();
if (ret == 0)
- ret = notify_change(&nop_mnt_idmap, file->f_path.dentry,
+ ret = notify_change(&nop_mnt_idmap, &file->f_path,
&newattrs, NULL);

truncate_failed:
diff --git a/fs/coredump.c b/fs/coredump.c
index ece7badf701b..01bef4830bfa 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -736,7 +736,7 @@ void do_coredump(const kernel_siginfo_t *siginfo)
}
if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
goto close_fail;
- if (do_truncate(idmap, cprm.file->f_path.dentry,
+ if (do_truncate(idmap, &cprm.file->f_path,
0, 0, cprm.file))
goto close_fail;
}
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 83274915ba6d..423bd457623e 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -853,12 +853,12 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)

rc = truncate_upper(dentry, &ia, &lower_ia);
if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
- struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+ const struct path *lower_path = ecryptfs_dentry_to_lower_path(dentry);

- inode_lock(d_inode(lower_dentry));
- rc = notify_change(&nop_mnt_idmap, lower_dentry,
+ inode_lock(d_inode(lower_path->dentry));
+ rc = notify_change(&nop_mnt_idmap, lower_path,
&lower_ia, NULL);
- inode_unlock(d_inode(lower_dentry));
+ inode_unlock(d_inode(lower_path->dentry));
}
return rc;
}
@@ -888,7 +888,7 @@ static int ecryptfs_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *ia)
{
int rc = 0;
- struct dentry *lower_dentry;
+ const struct path *lower_path;
struct iattr lower_ia;
struct inode *inode;
struct inode *lower_inode;
@@ -902,7 +902,7 @@ static int ecryptfs_setattr(struct mnt_idmap *idmap,
}
inode = d_inode(dentry);
lower_inode = ecryptfs_inode_to_lower(inode);
- lower_dentry = ecryptfs_dentry_to_lower(dentry);
+ lower_path = ecryptfs_dentry_to_lower_path(dentry);
mutex_lock(&crypt_stat->cs_mutex);
if (d_is_dir(dentry))
crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
@@ -964,9 +964,9 @@ static int ecryptfs_setattr(struct mnt_idmap *idmap,
if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
lower_ia.ia_valid &= ~ATTR_MODE;

- inode_lock(d_inode(lower_dentry));
- rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL);
- inode_unlock(d_inode(lower_dentry));
+ inode_lock(d_inode(lower_path->dentry));
+ rc = notify_change(&nop_mnt_idmap, lower_path, &lower_ia, NULL);
+ inode_unlock(d_inode(lower_path->dentry));
out:
fsstack_copy_attr_all(inode, lower_inode);
return rc;
diff --git a/fs/inode.c b/fs/inode.c
index 577799b7855f..4fa51d46f655 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1973,7 +1973,7 @@ int dentry_needs_remove_privs(struct mnt_idmap *idmap,
}

static int __remove_privs(struct mnt_idmap *idmap,
- struct dentry *dentry, int kill)
+ struct path *path, int kill)
{
struct iattr newattrs;

@@ -1982,13 +1982,15 @@ static int __remove_privs(struct mnt_idmap *idmap,
* Note we call this on write, so notify_change will not
* encounter any conflicting delegations:
*/
- return notify_change(idmap, dentry, &newattrs, NULL);
+ return notify_change(idmap, path, &newattrs, NULL);
}

static int __file_remove_privs(struct file *file, unsigned int flags)
{
struct dentry *dentry = file_dentry(file);
struct inode *inode = file_inode(file);
+ /* this path maybe incorrect */
+ struct path path = {.mnt = file->f_path.mnt, .dentry = dentry};
int error = 0;
int kill;

@@ -2003,7 +2005,7 @@ static int __file_remove_privs(struct file *file, unsigned int flags)
if (flags & IOCB_NOWAIT)
return -EAGAIN;

- error = __remove_privs(file_mnt_idmap(file), dentry, kill);
+ error = __remove_privs(file_mnt_idmap(file), &path, kill);
}

if (!error)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index cb93fd231f4e..2b7e5c446397 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -5644,8 +5644,8 @@ static int set_file_basic_info(struct ksmbd_file *fp,
}

if (attrs.ia_valid) {
- struct dentry *dentry = filp->f_path.dentry;
- struct inode *inode = d_inode(dentry);
+ struct path *path = &filp->f_path;
+ struct inode *inode = d_inode(path->dentry);

if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
return -EACCES;
@@ -5653,7 +5653,7 @@ static int set_file_basic_info(struct ksmbd_file *fp,
inode_lock(inode);
inode->i_ctime = attrs.ia_ctime;
attrs.ia_valid &= ~ATTR_CTIME;
- rc = notify_change(idmap, dentry, &attrs, NULL);
+ rc = notify_change(idmap, path, &attrs, NULL);
inode_unlock(inode);
}
return rc;
diff --git a/fs/ksmbd/smbacl.c b/fs/ksmbd/smbacl.c
index 6d6cfb6957a9..39d8aff3ae1b 100644
--- a/fs/ksmbd/smbacl.c
+++ b/fs/ksmbd/smbacl.c
@@ -1403,7 +1403,7 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon,
}

inode_lock(inode);
- rc = notify_change(idmap, path->dentry, &newattrs, NULL);
+ rc = notify_change(idmap, path, &newattrs, NULL);
inode_unlock(inode);
if (rc)
goto out;
diff --git a/fs/namei.c b/fs/namei.c
index e4fe0879ae55..ec7075a8505d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3292,7 +3292,7 @@ static int handle_truncate(struct mnt_idmap *idmap, struct file *filp)

error = security_file_truncate(filp);
if (!error) {
- error = do_truncate(idmap, path->dentry, 0,
+ error = do_truncate(idmap, path, 0,
ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
filp);
}
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index bb9d47172162..4b51fd2f05e3 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -410,7 +410,7 @@ nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
return nfserrno(get_write_access(inode));
}

-static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
+static int __nfsd_setattr(struct path *path, struct iattr *iap)
{
int host_err;

@@ -430,7 +430,7 @@ static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
if (iap->ia_size < 0)
return -EFBIG;

- host_err = notify_change(&nop_mnt_idmap, dentry, &size_attr, NULL);
+ host_err = notify_change(&nop_mnt_idmap, path, &size_attr, NULL);
if (host_err)
return host_err;
iap->ia_valid &= ~ATTR_SIZE;
@@ -448,7 +448,7 @@ static int __nfsd_setattr(struct dentry *dentry, struct iattr *iap)
return 0;

iap->ia_valid |= ATTR_CTIME;
- return notify_change(&nop_mnt_idmap, dentry, iap, NULL);
+ return notify_change(&nop_mnt_idmap, path, iap, NULL);
}

/**
@@ -471,6 +471,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct nfsd_attrs *attr,
int check_guard, time64_t guardtime)
{
+ struct path path;
struct dentry *dentry;
struct inode *inode;
struct iattr *iap = attr->na_iattr;
@@ -534,9 +535,12 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
return err;
}

+ path.mnt = fhp->fh_export->ex_path.mnt;
+ path.dentry = fhp->fh_dentry;
+
inode_lock(inode);
for (retries = 1;;) {
- host_err = __nfsd_setattr(dentry, iap);
+ host_err = __nfsd_setattr(&path, iap);
if (host_err != -EAGAIN || !retries--)
break;
if (!nfsd_wait_for_delegreturn(rqstp, inode))
diff --git a/fs/open.c b/fs/open.c
index 4478adcc4f3a..7a7841606285 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -37,11 +37,12 @@

#include "internal.h"

-int do_truncate(struct mnt_idmap *idmap, struct dentry *dentry,
+int do_truncate(struct mnt_idmap *idmap, const struct path *path,
loff_t length, unsigned int time_attrs, struct file *filp)
{
int ret;
struct iattr newattrs;
+ struct dentry *dentry = path->dentry;

/* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
if (length < 0)
@@ -63,7 +64,7 @@ int do_truncate(struct mnt_idmap *idmap, struct dentry *dentry,

inode_lock(dentry->d_inode);
/* Note any delegations or leases have already been broken: */
- ret = notify_change(idmap, dentry, &newattrs, NULL);
+ ret = notify_change(idmap, path, &newattrs, NULL);
inode_unlock(dentry->d_inode);
return ret;
}
@@ -109,7 +110,7 @@ long vfs_truncate(const struct path *path, loff_t length)

error = security_path_truncate(path);
if (!error)
- error = do_truncate(idmap, path->dentry, length, 0, NULL);
+ error = do_truncate(idmap, path, length, 0, NULL);

put_write_and_out:
put_write_access(inode);
@@ -157,7 +158,7 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length
long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
{
struct inode *inode;
- struct dentry *dentry;
+ struct path *path;
struct fd f;
int error;

@@ -173,8 +174,8 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
if (f.file->f_flags & O_LARGEFILE)
small = 0;

- dentry = f.file->f_path.dentry;
- inode = dentry->d_inode;
+ path = &f.file->f_path;
+ inode = d_inode(path->dentry);
error = -EINVAL;
if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
goto out_putf;
@@ -191,7 +192,7 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
sb_start_write(inode->i_sb);
error = security_file_truncate(f.file);
if (!error)
- error = do_truncate(file_mnt_idmap(f.file), dentry, length,
+ error = do_truncate(file_mnt_idmap(f.file), path, length,
ATTR_MTIME | ATTR_CTIME, f.file);
sb_end_write(inode->i_sb);
out_putf:
@@ -640,7 +641,7 @@ int chmod_common(const struct path *path, umode_t mode)
goto out_unlock;
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
- error = notify_change(mnt_idmap(path->mnt), path->dentry,
+ error = notify_change(mnt_idmap(path->mnt), path,
&newattrs, &delegated_inode);
out_unlock:
inode_unlock(inode);
@@ -771,7 +772,7 @@ int chown_common(const struct path *path, uid_t user, gid_t group)
from_vfsuid(idmap, fs_userns, newattrs.ia_vfsuid),
from_vfsgid(idmap, fs_userns, newattrs.ia_vfsgid));
if (!error)
- error = notify_change(idmap, path->dentry, &newattrs,
+ error = notify_change(idmap, path, &newattrs,
&delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 4d0b278f5630..d1a1eaa1c00c 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -141,7 +141,9 @@ static inline int ovl_do_notify_change(struct ovl_fs *ofs,
struct dentry *upperdentry,
struct iattr *attr)
{
- return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
+ struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = upperdentry };
+
+ return notify_change(ovl_upper_mnt_idmap(ofs), &path, attr, NULL);
}

static inline int ovl_do_rmdir(struct ovl_fs *ofs,
diff --git a/fs/utimes.c b/fs/utimes.c
index 3701b3946f88..1e6b82b27899 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -63,7 +63,7 @@ int vfs_utimes(const struct path *path, struct timespec64 *times)
}
retry_deleg:
inode_lock(inode);
- error = notify_change(mnt_idmap(path->mnt), path->dentry, &newattrs,
+ error = notify_change(mnt_idmap(path->mnt), path, &newattrs,
&delegated_inode);
inode_unlock(inode);
if (delegated_inode) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 21a981680856..dbba36ab4a1b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2333,7 +2333,7 @@ static inline bool is_idmapped_mnt(const struct vfsmount *mnt)
}

extern long vfs_truncate(const struct path *, loff_t);
-int do_truncate(struct mnt_idmap *, struct dentry *, loff_t start,
+int do_truncate(struct mnt_idmap *, const struct path *, loff_t start,
unsigned int time_attrs, struct file *filp);
extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
loff_t len);
@@ -2488,7 +2488,7 @@ static inline int bmap(struct inode *inode, sector_t *block)
}
#endif

-int notify_change(struct mnt_idmap *, struct dentry *,
+int notify_change(struct mnt_idmap *, const struct path *,
struct iattr *, struct inode **);
int inode_permission(struct mnt_idmap *, struct inode *, int);
int generic_permission(struct mnt_idmap *, struct inode *, int);
--
2.17.1