> On May 5, 2023, at 4:11 AM, Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> wrote:
>
> 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))
Acked-by: Chuck Lever <chuck.lever@xxxxxxxxxx <mailto:chuck.lever@xxxxxxxxxx>>
> 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
>
--
Chuck Lever
--
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