Al pointed out that ksmbd has racy issue from using ->d_parent and ->d_name
in ksmbd_vfs_unlink and smb2_vfs_rename(). and use new lock_rename_child()
to lock stable parent while underlying rename racy.
Introduce vfs_path_parent_lookup helper to avoid out of share access and
export vfs functions like the following ones to use
vfs_path_parent_lookup().
- export __lookup_hash().
- export getname_kernel() and putname().
vfs_path_parent_lookup() is used for parent lookup of destination file
using absolute pathname given from FILE_RENAME_INFORMATION request.
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
---
fs/ksmbd/smb2pdu.c | 105 ++-------------
fs/ksmbd/vfs.c | 302 ++++++++++++++++--------------------------
fs/ksmbd/vfs.h | 10 +-
fs/ksmbd/vfs_cache.c | 5 +-
fs/namei.c | 41 +++++-
include/linux/namei.h | 5 +
6 files changed, 172 insertions(+), 296 deletions(-)
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 16c803a9d996..d3e29f60fa2e 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -5362,44 +5362,19 @@ int smb2_echo(struct ksmbd_work *work)
static int smb2_rename(struct ksmbd_work *work,
struct ksmbd_file *fp,
- struct user_namespace *user_ns,
struct smb2_file_rename_info *file_info,
struct nls_table *local_nls)
{
struct ksmbd_share_config *share = fp->tcon->share_conf;
- char *new_name = NULL, *abs_oldname = NULL, *old_name = NULL;
- char *pathname = NULL;
- struct path path;
- bool file_present = true;
- int rc;
+ char *new_name = NULL;
+ int rc, flags = 0;
ksmbd_debug(SMB, "setting FILE_RENAME_INFO\n");
- pathname = kmalloc(PATH_MAX, GFP_KERNEL);
- if (!pathname)
- return -ENOMEM;
-
- abs_oldname = d_path(&fp->filp->f_path, pathname, PATH_MAX);
- if (IS_ERR(abs_oldname)) {
- rc = -EINVAL;
- goto out;
- }
- old_name = strrchr(abs_oldname, '/');
- if (old_name && old_name[1] != '\0') {
- old_name++;
- } else {
- ksmbd_debug(SMB, "can't get last component in path %s\n",
- abs_oldname);
- rc = -ENOENT;
- goto out;
- }
-
new_name = smb2_get_name(file_info->FileName,
le32_to_cpu(file_info->FileNameLength),
local_nls);
- if (IS_ERR(new_name)) {
- rc = PTR_ERR(new_name);
- goto out;
- }
+ if (IS_ERR(new_name))
+ return PTR_ERR(new_name);
if (strchr(new_name, ':')) {
int s_type;
@@ -5425,7 +5400,7 @@ static int smb2_rename(struct ksmbd_work *work,
if (rc)
goto out;
- rc = ksmbd_vfs_setxattr(user_ns,
+ rc = ksmbd_vfs_setxattr(file_mnt_user_ns(fp->filp),
fp->filp->f_path.dentry,
xattr_stream_name,
NULL, 0, 0);
@@ -5440,47 +5415,18 @@ static int smb2_rename(struct ksmbd_work *work,
}
ksmbd_debug(SMB, "new name %s\n", new_name);
- rc = ksmbd_vfs_kern_path(work, new_name, LOOKUP_NO_SYMLINKS, &path, 1);
- if (rc) {
- if (rc != -ENOENT)
- goto out;
- file_present = false;
- } else {
- path_put(&path);
- }
-
if (ksmbd_share_veto_filename(share, new_name)) {
rc = -ENOENT;
ksmbd_debug(SMB, "Can't rename vetoed file: %s\n", new_name);
goto out;
}
- if (file_info->ReplaceIfExists) {
- if (file_present) {
- rc = ksmbd_vfs_remove_file(work, new_name);
- if (rc) {
- if (rc != -ENOTEMPTY)
- rc = -EINVAL;
- ksmbd_debug(SMB, "cannot delete %s, rc %d\n",
- new_name, rc);
- goto out;
- }
- }
- } else {
- if (file_present &&
- strncmp(old_name, path.dentry->d_name.name, strlen(old_name))) {
- rc = -EEXIST;
- ksmbd_debug(SMB,
- "cannot rename already existing file\n");
- goto out;
- }
- }
+ if (!file_info->ReplaceIfExists)
+ flags = RENAME_NOREPLACE;
- rc = ksmbd_vfs_fp_rename(work, fp, new_name);
+ rc = ksmbd_vfs_rename(work, &fp->filp->f_path, new_name, flags);
out:
- kfree(pathname);
- if (!IS_ERR(new_name))
- kfree(new_name);
+ kfree(new_name);
return rc;
}
@@ -5728,12 +5674,6 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
struct smb2_file_rename_info *rename_info,
unsigned int buf_len)
{
- struct user_namespace *user_ns;
- struct ksmbd_file *parent_fp;
- struct dentry *parent;
- struct dentry *dentry = fp->filp->f_path.dentry;
- int ret;
-
if (!(fp->daccess & FILE_DELETE_LE)) {
pr_err("no right to delete : 0x%x\n", fp->daccess);
return -EACCES;
@@ -5743,32 +5683,7 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
le32_to_cpu(rename_info->FileNameLength))
return -EINVAL;
- user_ns = file_mnt_user_ns(fp->filp);
- if (ksmbd_stream_fd(fp))
- goto next;
-
- parent = dget_parent(dentry);
- ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
- if (ret) {
- dput(parent);
- return ret;
- }
-
- parent_fp = ksmbd_lookup_fd_inode(d_inode(parent));
- inode_unlock(d_inode(parent));
- dput(parent);
-
- if (parent_fp) {
- if (parent_fp->daccess & FILE_DELETE_LE) {
- pr_err("parent dir is opened with delete access\n");
- ksmbd_fd_put(work, parent_fp);
- return -ESHARE;
- }
- ksmbd_fd_put(work, parent_fp);
- }
-next:
- return smb2_rename(work, fp, user_ns, rename_info,
- work->sess->conn->local_nls);
+ return smb2_rename(work, fp, rename_info, work->sess->conn->local_nls);
}
static int set_file_disposition_info(struct ksmbd_file *fp,
diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c
index f79dfcebe480..93d3625bf6d1 100644
--- a/fs/ksmbd/vfs.c
+++ b/fs/ksmbd/vfs.c
@@ -17,6 +17,7 @@
#include <linux/vmalloc.h>
#include <linux/sched/xacct.h>
#include <linux/crc32c.h>
+#include <linux/namei.h>
#include "glob.h"
#include "oplock.h"
@@ -34,19 +35,6 @@
#include "mgmt/user_session.h"
#include "mgmt/user_config.h"
-static char *extract_last_component(char *path)
-{
- char *p = strrchr(path, '/');
-
- if (p && p[1] != '\0') {
- *p = '\0';
- p++;
- } else {
- p = NULL;
- }
- return p;
-}
-
static void ksmbd_vfs_inherit_owner(struct ksmbd_work *work,
struct inode *parent_inode,
struct inode *inode)
@@ -60,38 +48,20 @@ static void ksmbd_vfs_inherit_owner(struct ksmbd_work *work,
/**
* ksmbd_vfs_lock_parent() - lock parent dentry if it is stable
- *
- * the parent dentry got by dget_parent or @parent could be
- * unstable, we try to lock a parent inode and lookup the
- * child dentry again.
- *
- * the reference count of @parent isn't incremented.
*/
-int ksmbd_vfs_lock_parent(struct user_namespace *user_ns, struct dentry *parent,
- struct dentry *child)
+struct dentry *ksmbd_vfs_lock_parent(struct dentry *child)
{
- struct dentry *dentry;
- int ret = 0;
+ struct dentry *parent;
+ parent = dget(child->d_parent);
inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
- dentry = lookup_one(user_ns, child->d_name.name, parent,
- child->d_name.len);
- if (IS_ERR(dentry)) {
- ret = PTR_ERR(dentry);
- goto out_err;
- }
-
- if (dentry != child) {
- ret = -ESTALE;
- dput(dentry);
- goto out_err;
+ if (child->d_parent != parent) {
+ dput(parent);
+ inode_unlock(d_inode(parent));
+ return ERR_PTR(-EINVAL);
}
- dput(dentry);
- return 0;
-out_err:
- inode_unlock(d_inode(parent));
- return ret;
+ return parent;
}
int ksmbd_vfs_may_delete(struct user_namespace *user_ns,
@@ -100,12 +70,9 @@ int ksmbd_vfs_may_delete(struct user_namespace *user_ns,
struct dentry *parent;
int ret;
- parent = dget_parent(dentry);
- ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
- if (ret) {
- dput(parent);
- return ret;
- }
+ parent = ksmbd_vfs_lock_parent(dentry);
+ if (IS_ERR(parent))
+ return PTR_ERR(parent);
ret = inode_permission(user_ns, d_inode(parent),
MAY_EXEC | MAY_WRITE);
@@ -135,12 +102,9 @@ int ksmbd_vfs_query_maximal_access(struct user_namespace *user_ns,
if (!inode_permission(user_ns, d_inode(dentry), MAY_OPEN | MAY_EXEC))
*daccess |= FILE_EXECUTE_LE;
- parent = dget_parent(dentry);
- ret = ksmbd_vfs_lock_parent(user_ns, parent, dentry);
- if (ret) {
- dput(parent);
- return ret;
- }
+ parent = ksmbd_vfs_lock_parent(dentry);
+ if (IS_ERR(parent))
+ return PTR_ERR(parent);
if (!inode_permission(user_ns, d_inode(parent), MAY_EXEC | MAY_WRITE))
*daccess |= FILE_DELETE_LE;
@@ -599,14 +563,11 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
return err;
}
- user_ns = mnt_user_ns(path.mnt);
- parent = dget_parent(path.dentry);
- err = ksmbd_vfs_lock_parent(user_ns, parent, path.dentry);
- if (err) {
- dput(parent);
+ parent = ksmbd_vfs_lock_parent(path.dentry);
+ if (IS_ERR(parent)) {
path_put(&path);
ksmbd_revert_fsids(work);
- return err;
+ return PTR_ERR(parent);
}
if (!d_inode(path.dentry)->i_nlink) {
@@ -614,6 +575,7 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name)
goto out_err;
}
+ user_ns = mnt_user_ns(path.mnt);
if (S_ISDIR(d_inode(path.dentry)->i_mode)) {
err = vfs_rmdir(user_ns, d_inode(parent), path.dentry);
if (err && err != -ENOTEMPTY)
@@ -688,149 +650,114 @@ int ksmbd_vfs_link(struct ksmbd_work *work, const char *oldname,
return err;
}
-static int ksmbd_validate_entry_in_use(struct dentry *src_dent)
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct path *old_path,
+ char *newname, int flags)
{
- struct dentry *dst_dent;
-
- spin_lock(&src_dent->d_lock);
- list_for_each_entry(dst_dent, &src_dent->d_subdirs, d_child) {
- struct ksmbd_file *child_fp;
+ struct dentry *old_parent, *new_dentry, *trap;
+ struct dentry *old_child = old_path->dentry;
+ struct path new_path;
+ struct qstr new_last;
+ struct renamedata rd;
+ struct filename *to;
+ struct ksmbd_share_config *share_conf = work->tcon->share_conf;
+ struct ksmbd_file *parent_fp;
+ int new_type;
+ int err, lookup_flags = LOOKUP_NO_SYMLINKS;
- if (d_really_is_negative(dst_dent))
- continue;
+ if (ksmbd_override_fsids(work))
+ return -ENOMEM;
- child_fp = ksmbd_lookup_fd_inode(d_inode(dst_dent));
- if (child_fp) {
- spin_unlock(&src_dent->d_lock);
- ksmbd_debug(VFS, "Forbid rename, sub file/dir is in use\n");
- return -EACCES;
- }
+ to = getname_kernel(newname);
+ if (IS_ERR(to)) {
+ err = PTR_ERR(to);
+ goto revert_fsids;
}
- spin_unlock(&src_dent->d_lock);
- return 0;
-}
+retry:
+ err = vfs_path_parent_lookup(to, lookup_flags | LOOKUP_BENEATH,
+ &new_path, &new_last, &new_type,
+ &share_conf->vfs_path);
+ if (err)
+ goto out1;
-static int __ksmbd_vfs_rename(struct ksmbd_work *work,
- struct user_namespace *src_user_ns,
- struct dentry *src_dent_parent,
- struct dentry *src_dent,
- struct user_namespace *dst_user_ns,
- struct dentry *dst_dent_parent,
- struct dentry *trap_dent,
- char *dst_name)
-{
- struct dentry *dst_dent;
- int err;
+ if (old_path->mnt != new_path.mnt) {
+ err = -EXDEV;
+ goto out2;
+ }
- if (!work->tcon->posix_extensions) {
- err = ksmbd_validate_entry_in_use(src_dent);
- if (err)
- return err;
+ trap = lock_rename_child(old_child, new_path.dentry);
+
+ old_parent = dget(old_child->d_parent);
+ if (d_unhashed(old_child)) {
+ err = -EINVAL;
+ goto out3;
}
- if (d_really_is_negative(src_dent_parent))
- return -ENOENT;
- if (d_really_is_negative(dst_dent_parent))
- return -ENOENT;
- if (d_really_is_negative(src_dent))
- return -ENOENT;
- if (src_dent == trap_dent)
- return -EINVAL;
+ parent_fp = ksmbd_lookup_fd_inode(d_inode(old_child->d_parent));
+ if (parent_fp) {
+ if (parent_fp->daccess & FILE_DELETE_LE) {
+ pr_err("parent dir is opened with delete access\n");
+ err = -ESHARE;
+ ksmbd_fd_put(work, parent_fp);
+ goto out3;
+ }
+ ksmbd_fd_put(work, parent_fp);
+ }
- if (ksmbd_override_fsids(work))
- return -ENOMEM;
+ new_dentry = __lookup_hash(&new_last, new_path.dentry,
+ lookup_flags | LOOKUP_RENAME_TARGET);
+ if (IS_ERR(new_dentry)) {
+ err = PTR_ERR(new_dentry);
+ goto out3;
+ }
- dst_dent = lookup_one(dst_user_ns, dst_name, dst_dent_parent,
- strlen(dst_name));
- err = PTR_ERR(dst_dent);
- if (IS_ERR(dst_dent)) {
- pr_err("lookup failed %s [%d]\n", dst_name, err);
- goto out;
+ if (d_is_symlink(new_dentry)) {
+ err = -EACCES;
+ goto out4;
}
- err = -ENOTEMPTY;
- if (dst_dent != trap_dent && !d_really_is_positive(dst_dent)) {
- struct renamedata rd = {
- .old_mnt_userns = src_user_ns,
- .old_dir = d_inode(src_dent_parent),
- .old_dentry = src_dent,
- .new_mnt_userns = dst_user_ns,
- .new_dir = d_inode(dst_dent_parent),
- .new_dentry = dst_dent,
- };
- err = vfs_rename(&rd);
+ if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) {
+ err = -EEXIST;
+ goto out4;
}
- if (err)
- pr_err("vfs_rename failed err %d\n", err);
- if (dst_dent)
- dput(dst_dent);
-out:
- ksmbd_revert_fsids(work);
- return err;
-}
-int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
- char *newname)
-{
- struct user_namespace *user_ns;
- struct path dst_path;
- struct dentry *src_dent_parent, *dst_dent_parent;
- struct dentry *src_dent, *trap_dent, *src_child;
- char *dst_name;
- int err;
+ if (old_child == trap) {
+ err = -EINVAL;
+ goto out4;
+ }
- dst_name = extract_last_component(newname);
- if (!dst_name) {
- dst_name = newname;
- newname = "";
+ if (new_dentry == trap) {
+ err = -ENOTEMPTY;
+ goto out4;
}
- src_dent_parent = dget_parent(fp->filp->f_path.dentry);
- src_dent = fp->filp->f_path.dentry;
+ rd.old_mnt_userns = mnt_user_ns(old_path->mnt),
+ rd.old_dir = d_inode(old_parent),
+ rd.old_dentry = old_child,
+ rd.new_mnt_userns = mnt_user_ns(new_path.mnt),
+ rd.new_dir = new_path.dentry->d_inode,
+ rd.new_dentry = new_dentry,
+ rd.flags = flags,
+ err = vfs_rename(&rd);
+ if (err)
+ ksmbd_debug(VFS, "vfs_rename failed err %d\n", err);
- err = ksmbd_vfs_kern_path(work, newname,
- LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY,
- &dst_path, false);
- if (err) {
- ksmbd_debug(VFS, "Cannot get path for %s [%d]\n", newname, err);
- goto out;
+out4:
+ dput(new_dentry);
+out3:
+ dput(old_parent);
+ unlock_rename(old_parent, new_path.dentry);
+out2:
+ path_put(&new_path);
+
+ if (retry_estale(err, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
}
- dst_dent_parent = dst_path.dentry;
-
- trap_dent = lock_rename(src_dent_parent, dst_dent_parent);
- dget(src_dent);
- dget(dst_dent_parent);
- user_ns = file_mnt_user_ns(fp->filp);
- src_child = lookup_one(user_ns, src_dent->d_name.name, src_dent_parent,
- src_dent->d_name.len);
- if (IS_ERR(src_child)) {
- err = PTR_ERR(src_child);
- goto out_lock;
- }
-
- if (src_child != src_dent) {
- err = -ESTALE;
- dput(src_child);
- goto out_lock;
- }
- dput(src_child);
-
- err = __ksmbd_vfs_rename(work,
- user_ns,
- src_dent_parent,
- src_dent,
- mnt_user_ns(dst_path.mnt),
- dst_dent_parent,
- trap_dent,
- dst_name);
-out_lock:
- dput(src_dent);
- dput(dst_dent_parent);
- unlock_rename(src_dent_parent, dst_dent_parent);
- path_put(&dst_path);
-out:
- dput(src_dent_parent);
+out1:
+ putname(to);
+revert_fsids:
+ ksmbd_revert_fsids(work);
return err;
}
@@ -1079,14 +1006,17 @@ int ksmbd_vfs_remove_xattr(struct user_namespace *user_ns,
return vfs_removexattr(user_ns, dentry, attr_name);
}
-int ksmbd_vfs_unlink(struct user_namespace *user_ns,
- struct dentry *dir, struct dentry *dentry)
+int ksmbd_vfs_unlink(struct file *filp)
{
int err = 0;
+ struct dentry *dir, *dentry = filp->f_path.dentry;
+ struct user_namespace *user_ns = file_mnt_user_ns(filp);
- err = ksmbd_vfs_lock_parent(user_ns, dir, dentry);
- if (err)
- return err;
+ dir = ksmbd_vfs_lock_parent(dentry);
+ if (IS_ERR(dir)) {
+ err = PTR_ERR(dir);
+ goto out;
+ }
dget(dentry);
if (S_ISDIR(d_inode(dentry)->i_mode))
@@ -1098,6 +1028,8 @@ int ksmbd_vfs_unlink(struct user_namespace *user_ns,
inode_unlock(d_inode(dir));
if (err)
ksmbd_debug(VFS, "failed to delete, err %d\n", err);
+out:
+ dput(dir);
return err;
}
diff --git a/fs/ksmbd/vfs.h b/fs/ksmbd/vfs.h
index 8c37aaf936ab..f79e73b6f01b 100644
--- a/fs/ksmbd/vfs.h
+++ b/fs/ksmbd/vfs.h
@@ -69,8 +69,7 @@ struct ksmbd_kstat {
__le32 file_attributes;
};
-int ksmbd_vfs_lock_parent(struct user_namespace *user_ns, struct dentry *parent,
- struct dentry *child);
+struct dentry *ksmbd_vfs_lock_parent(struct dentry *child);
int ksmbd_vfs_may_delete(struct user_namespace *user_ns, struct dentry *dentry);
int ksmbd_vfs_query_maximal_access(struct user_namespace *user_ns,
struct dentry *dentry, __le32 *daccess);
@@ -86,8 +85,8 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name);
int ksmbd_vfs_link(struct ksmbd_work *work,
const char *oldname, const char *newname);
int ksmbd_vfs_getattr(struct path *path, struct kstat *stat);
-int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp,
- char *newname);
+int ksmbd_vfs_rename(struct ksmbd_work *work, struct path *old_path,
+ char *newname, int flags);
int ksmbd_vfs_truncate(struct ksmbd_work *work,
struct ksmbd_file *fp, loff_t size);
struct srv_copychunk;
@@ -129,8 +128,7 @@ struct file_allocated_range_buffer;
int ksmbd_vfs_fqar_lseek(struct ksmbd_file *fp, loff_t start, loff_t length,
struct file_allocated_range_buffer *ranges,
unsigned int in_count, unsigned int *out_count);
-int ksmbd_vfs_unlink(struct user_namespace *user_ns,
- struct dentry *dir, struct dentry *dentry);
+int ksmbd_vfs_unlink(struct file *filp);
void *ksmbd_vfs_init_kstat(char **p, struct ksmbd_kstat *ksmbd_kstat);
int ksmbd_vfs_fill_dentry_attrs(struct ksmbd_work *work,
struct user_namespace *user_ns,
diff --git a/fs/ksmbd/vfs_cache.c b/fs/ksmbd/vfs_cache.c
index c4d59d2735f0..df600eb04552 100644
--- a/fs/ksmbd/vfs_cache.c
+++ b/fs/ksmbd/vfs_cache.c
@@ -243,7 +243,6 @@ void ksmbd_release_inode_hash(void)
static void __ksmbd_inode_close(struct ksmbd_file *fp)
{
- struct dentry *dir, *dentry;
struct ksmbd_inode *ci = fp->f_ci;
int err;
struct file *filp;
@@ -262,11 +261,9 @@ static void __ksmbd_inode_close(struct ksmbd_file *fp)
if (atomic_dec_and_test(&ci->m_count)) {
write_lock(&ci->m_lock);
if (ci->m_flags & (S_DEL_ON_CLS | S_DEL_PENDING)) {
- dentry = filp->f_path.dentry;
- dir = dentry->d_parent;
ci->m_flags &= ~(S_DEL_ON_CLS | S_DEL_PENDING);
write_unlock(&ci->m_lock);
- ksmbd_vfs_unlink(file_mnt_user_ns(filp), dir, dentry);
+ ksmbd_vfs_unlink(filp);
write_lock(&ci->m_lock);
}
write_unlock(&ci->m_lock);
diff --git a/fs/namei.c b/fs/namei.c
index 516b8d147744..1c0de16f9cb9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -252,6 +252,7 @@ getname_kernel(const char * filename)
return result;
}
+EXPORT_SYMBOL(getname_kernel);
void putname(struct filename *name)
{
@@ -269,6 +270,7 @@ void putname(struct filename *name)
} else
__putname(name);
}
+EXPORT_SYMBOL(putname);
/**
* check_acl - perform ACL permission checking
@@ -1587,8 +1589,8 @@ static struct dentry *lookup_dcache(const struct qstr *name,
* when directory is guaranteed to have no in-lookup children
* at all.
*/
-static struct dentry *__lookup_hash(const struct qstr *name,
- struct dentry *base, unsigned int flags)
+struct dentry *__lookup_hash(const struct qstr *name, struct dentry *base,
+ unsigned int flags)
{
struct dentry *dentry = lookup_dcache(name, base, flags);
struct dentry *old;
@@ -1612,6 +1614,7 @@ static struct dentry *__lookup_hash(const struct qstr *name,
}
return dentry;
}
+EXPORT_SYMBOL(__lookup_hash);
static struct dentry *lookup_fast(struct nameidata *nd,
struct inode **inode,
@@ -2556,16 +2559,17 @@ static int path_parentat(struct nameidata *nd, unsigned flags,
}
/* Note: this does not consume "name" */
-static int filename_parentat(int dfd, struct filename *name,
- unsigned int flags, struct path *parent,
- struct qstr *last, int *type)
+static int __filename_parentat(int dfd, struct filename *name,
+ unsigned int flags, struct path *parent,
+ struct qstr *last, int *type,
+ const struct path *root)
{
int retval;
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
- set_nameidata(&nd, dfd, name, NULL);
+ set_nameidata(&nd, dfd, name, root);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(&nd, flags, parent);
@@ -2580,6 +2584,13 @@ static int filename_parentat(int dfd, struct filename *name,
return retval;
}
+static int filename_parentat(int dfd, struct filename *name,
+ unsigned int flags, struct path *parent,
+ struct qstr *last, int *type)
+{
+ return __filename_parentat(dfd, name, flags, parent, last, type, NULL);
+}
+
/* does lookup, returns the object with parent locked */
static struct dentry *__kern_path_locked(struct filename *name, struct path *path)
{
@@ -2623,6 +2634,24 @@ int kern_path(const char *name, unsigned int flags, struct path *path)
}
EXPORT_SYMBOL(kern_path);
+/**
+ * vfs_path_parent_lookup - lookup a parent path relative to a dentry-vfsmount pair
+ * @filename: filename structure
+ * @flags: lookup flags
+ * @parent: pointer to struct path to fill
+ * @last: last component
+ * @type: type of the last component
+ * @root: pointer to struct path of the base directory
+ */
+int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
+ struct path *parent, struct qstr *last, int *type,
+ const struct path *root)
+{
+ return __filename_parentat(AT_FDCWD, filename, flags, parent, last,
+ type, root);
+}
+EXPORT_SYMBOL(vfs_path_parent_lookup);
+
/**
* vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
* @dentry: pointer to dentry of the base directory
diff --git a/include/linux/namei.h b/include/linux/namei.h
index e6949d4ba188..f9be815f12b0 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -57,12 +57,17 @@ static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
return user_path_at_empty(dfd, name, flags, path, NULL);
}
+struct dentry *__lookup_hash(const struct qstr *name, struct dentry *base,
+ unsigned int flags);
extern int kern_path(const char *, unsigned, struct path *);
extern struct dentry *kern_path_create(int, const char *, struct path *, unsigned int);
extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
extern void done_path_create(struct path *, struct dentry *);
extern struct dentry *kern_path_locked(const char *, struct path *);
+int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
+ struct path *parent, struct qstr *last, int *type,
+ const struct path *root);
int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *,
unsigned int, struct path *);
--
2.25.1
