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-rw-r--r--fs/overlayfs/Kconfig1
-rw-r--r--fs/overlayfs/Makefile1
-rw-r--r--fs/overlayfs/copy_up.c7
-rw-r--r--fs/overlayfs/dir.c7
-rw-r--r--fs/overlayfs/export.c5
-rw-r--r--fs/overlayfs/file.c101
-rw-r--r--fs/overlayfs/inode.c65
-rw-r--r--fs/overlayfs/namei.c13
-rw-r--r--fs/overlayfs/overlayfs.h8
-rw-r--r--fs/overlayfs/ovl_entry.h11
-rw-r--r--fs/overlayfs/readdir.c5
-rw-r--r--fs/overlayfs/super.c178
-rw-r--r--fs/overlayfs/util.c17
13 files changed, 317 insertions, 102 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 2ef91be2a04e..444e2da4f60e 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
config OVERLAY_FS
tristate "Overlay filesystem support"
select EXPORTFS
diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile
index 46e1ff8ac056..9164c585eb2f 100644
--- a/fs/overlayfs/Makefile
+++ b/fs/overlayfs/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
#
# Makefile for the overlay filesystem.
#
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 56feaa739979..b801c6353100 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/module.h>
@@ -37,7 +34,7 @@ static int ovl_ccup_get(char *buf, const struct kernel_param *param)
}
module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644);
-MODULE_PARM_DESC(ovl_check_copy_up, "Obsolete; does nothing");
+MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing");
int ovl_copy_xattr(struct dentry *old, struct dentry *new)
{
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 93872bb50230..702aa63f6774 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
@@ -21,7 +18,7 @@
static unsigned short ovl_redirect_max = 256;
module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
-MODULE_PARM_DESC(ovl_redirect_max,
+MODULE_PARM_DESC(redirect_max,
"Maximum length of absolute redirect xattr value");
static int ovl_set_redirect(struct dentry *dentry, bool samedir);
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index cc1c9e5606ba..cb8ec1f65c03 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Overlayfs NFS export support.
*
* Amir Goldstein <amir73il@gmail.com>
*
* Copyright (C) 2017-2018 CTERA Networks. All Rights Reserved.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 540a8b845145..e235a635d9ec 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2017 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/cred.h>
@@ -409,36 +406,16 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
return ret;
}
-static unsigned int ovl_get_inode_flags(struct inode *inode)
-{
- unsigned int flags = READ_ONCE(inode->i_flags);
- unsigned int ovl_iflags = 0;
-
- if (flags & S_SYNC)
- ovl_iflags |= FS_SYNC_FL;
- if (flags & S_APPEND)
- ovl_iflags |= FS_APPEND_FL;
- if (flags & S_IMMUTABLE)
- ovl_iflags |= FS_IMMUTABLE_FL;
- if (flags & S_NOATIME)
- ovl_iflags |= FS_NOATIME_FL;
-
- return ovl_iflags;
-}
-
-static long ovl_ioctl_set_flags(struct file *file, unsigned long arg)
+static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
+ unsigned long arg, unsigned int iflags)
{
long ret;
struct inode *inode = file_inode(file);
- unsigned int flags;
- unsigned int old_flags;
+ unsigned int old_iflags;
if (!inode_owner_or_capable(inode))
return -EACCES;
- if (get_user(flags, (int __user *) arg))
- return -EFAULT;
-
ret = mnt_want_write_file(file);
if (ret)
return ret;
@@ -447,8 +424,8 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned long arg)
/* Check the capability before cred override */
ret = -EPERM;
- old_flags = ovl_get_inode_flags(inode);
- if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
+ old_iflags = READ_ONCE(inode->i_flags);
+ if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
!capable(CAP_LINUX_IMMUTABLE))
goto unlock;
@@ -456,7 +433,7 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned long arg)
if (ret)
goto unlock;
- ret = ovl_real_ioctl(file, FS_IOC_SETFLAGS, arg);
+ ret = ovl_real_ioctl(file, cmd, arg);
ovl_copyflags(ovl_inode_real(inode), inode);
unlock:
@@ -468,17 +445,79 @@ unlock:
}
+static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
+{
+ unsigned int iflags = 0;
+
+ if (flags & FS_SYNC_FL)
+ iflags |= S_SYNC;
+ if (flags & FS_APPEND_FL)
+ iflags |= S_APPEND;
+ if (flags & FS_IMMUTABLE_FL)
+ iflags |= S_IMMUTABLE;
+ if (flags & FS_NOATIME_FL)
+ iflags |= S_NOATIME;
+
+ return iflags;
+}
+
+static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ unsigned int flags;
+
+ if (get_user(flags, (int __user *) arg))
+ return -EFAULT;
+
+ return ovl_ioctl_set_flags(file, cmd, arg,
+ ovl_fsflags_to_iflags(flags));
+}
+
+static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+{
+ unsigned int iflags = 0;
+
+ if (xflags & FS_XFLAG_SYNC)
+ iflags |= S_SYNC;
+ if (xflags & FS_XFLAG_APPEND)
+ iflags |= S_APPEND;
+ if (xflags & FS_XFLAG_IMMUTABLE)
+ iflags |= S_IMMUTABLE;
+ if (xflags & FS_XFLAG_NOATIME)
+ iflags |= S_NOATIME;
+
+ return iflags;
+}
+
+static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct fsxattr fa;
+
+ memset(&fa, 0, sizeof(fa));
+ if (copy_from_user(&fa, (void __user *) arg, sizeof(fa)))
+ return -EFAULT;
+
+ return ovl_ioctl_set_flags(file, cmd, arg,
+ ovl_fsxflags_to_iflags(fa.fsx_xflags));
+}
+
static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;
switch (cmd) {
case FS_IOC_GETFLAGS:
+ case FS_IOC_FSGETXATTR:
ret = ovl_real_ioctl(file, cmd, arg);
break;
case FS_IOC_SETFLAGS:
- ret = ovl_ioctl_set_flags(file, arg);
+ ret = ovl_ioctl_set_fsflags(file, cmd, arg);
+ break;
+
+ case FS_IOC_FSSETXATTR:
+ ret = ovl_ioctl_set_fsxflags(file, cmd, arg);
break;
default:
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b48273e846ad..7663aeb85fa3 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
@@ -553,15 +550,15 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
int xinobits = ovl_xino_bits(inode->i_sb);
/*
- * When NFS export is enabled and d_ino is consistent with st_ino
- * (samefs or i_ino has enough bits to encode layer), set the same
- * value used for d_ino to i_ino, because nfsd readdirplus compares
- * d_ino values to i_ino values of child entries. When called from
+ * When d_ino is consistent with st_ino (samefs or i_ino has enough
+ * bits to encode layer), set the same value used for st_ino to i_ino,
+ * so inode number exposed via /proc/locks and a like will be
+ * consistent with d_ino and st_ino values. An i_ino value inconsistent
+ * with d_ino also causes nfsd readdirplus to fail. When called from
* ovl_new_inode(), ino arg is 0, so i_ino will be updated to real
* upper inode i_ino on ovl_inode_init() or ovl_inode_update().
*/
- if (inode->i_sb->s_export_op &&
- (ovl_same_sb(inode->i_sb) || xinobits)) {
+ if (ovl_same_sb(inode->i_sb) || xinobits) {
inode->i_ino = ino;
if (xinobits && fsid && !(ino >> (64 - xinobits)))
inode->i_ino |= (unsigned long)fsid << (64 - xinobits);
@@ -777,6 +774,54 @@ struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
return inode;
}
+bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir)
+{
+ struct inode *key = d_inode(dir);
+ struct inode *trap;
+ bool res;
+
+ trap = ilookup5(sb, (unsigned long) key, ovl_inode_test, key);
+ if (!trap)
+ return false;
+
+ res = IS_DEADDIR(trap) && !ovl_inode_upper(trap) &&
+ !ovl_inode_lower(trap);
+
+ iput(trap);
+ return res;
+}
+
+/*
+ * Create an inode cache entry for layer root dir, that will intentionally
+ * fail ovl_verify_inode(), so any lookup that will find some layer root
+ * will fail.
+ */
+struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir)
+{
+ struct inode *key = d_inode(dir);
+ struct inode *trap;
+
+ if (!d_is_dir(dir))
+ return ERR_PTR(-ENOTDIR);
+
+ trap = iget5_locked(sb, (unsigned long) key, ovl_inode_test,
+ ovl_inode_set, key);
+ if (!trap)
+ return ERR_PTR(-ENOMEM);
+
+ if (!(trap->i_state & I_NEW)) {
+ /* Conflicting layer roots? */
+ iput(trap);
+ return ERR_PTR(-ELOOP);
+ }
+
+ trap->i_mode = S_IFDIR;
+ trap->i_flags = S_DEAD;
+ unlock_new_inode(trap);
+
+ return trap;
+}
+
/*
* Does overlay inode need to be hashed by lower inode?
*/
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index efd372312ef1..e9717c2f7d45 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Novell Inc.
* Copyright (C) 2016 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
@@ -18,6 +15,7 @@
#include "overlayfs.h"
struct ovl_lookup_data {
+ struct super_block *sb;
struct qstr name;
bool is_dir;
bool opaque;
@@ -244,6 +242,12 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
if (!d->metacopy || d->last)
goto out;
} else {
+ if (ovl_lookup_trap_inode(d->sb, this)) {
+ /* Caught in a trap of overlapping layers */
+ err = -ELOOP;
+ goto out_err;
+ }
+
if (last_element)
d->is_dir = true;
if (d->last)
@@ -819,6 +823,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
int err;
bool metacopy = false;
struct ovl_lookup_data d = {
+ .sb = dentry->d_sb,
.name = dentry->d_name,
.is_dir = false,
.opaque = false,
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index d26efed9f80a..6934bcf030f0 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -1,10 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/kernel.h>
@@ -270,6 +267,7 @@ void ovl_clear_flag(unsigned long flag, struct inode *inode);
bool ovl_test_flag(unsigned long flag, struct inode *inode);
bool ovl_inuse_trylock(struct dentry *dentry);
void ovl_inuse_unlock(struct dentry *dentry);
+bool ovl_is_inuse(struct dentry *dentry);
bool ovl_need_index(struct dentry *dentry);
int ovl_nlink_start(struct dentry *dentry);
void ovl_nlink_end(struct dentry *dentry);
@@ -376,6 +374,8 @@ struct ovl_inode_params {
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
bool is_upper);
+bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
+struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
struct inode *ovl_get_inode(struct super_block *sb,
struct ovl_inode_params *oip);
static inline void ovl_copyattr(struct inode *from, struct inode *to)
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index ec237035333a..28a2d12a1029 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -1,11 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
/*
*
* Copyright (C) 2011 Novell Inc.
* Copyright (C) 2016 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
struct ovl_config {
@@ -29,6 +26,8 @@ struct ovl_sb {
struct ovl_layer {
struct vfsmount *mnt;
+ /* Trap in ovl inode cache */
+ struct inode *trap;
struct ovl_sb *fs;
/* Index of this layer in fs root (upper idx == 0) */
int idx;
@@ -65,6 +64,10 @@ struct ovl_fs {
/* Did we take the inuse lock? */
bool upperdir_locked;
bool workdir_locked;
+ /* Traps in ovl inode cache */
+ struct inode *upperdir_trap;
+ struct inode *workdir_trap;
+ struct inode *indexdir_trap;
/* Inode numbers in all layers do not use the high xino_bits */
unsigned int xino_bits;
};
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index cc8303a806b4..47a91c9733a5 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 5ec4fc2f5d7e..b368e2e102fa 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <uapi/linux/magic.h>
@@ -31,29 +28,29 @@ struct ovl_dir_cache;
static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
-MODULE_PARM_DESC(ovl_redirect_dir_def,
+MODULE_PARM_DESC(redirect_dir,
"Default to on or off for the redirect_dir feature");
static bool ovl_redirect_always_follow =
IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
module_param_named(redirect_always_follow, ovl_redirect_always_follow,
bool, 0644);
-MODULE_PARM_DESC(ovl_redirect_always_follow,
+MODULE_PARM_DESC(redirect_always_follow,
"Follow redirects even if redirect_dir feature is turned off");
static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
module_param_named(index, ovl_index_def, bool, 0644);
-MODULE_PARM_DESC(ovl_index_def,
+MODULE_PARM_DESC(index,
"Default to on or off for the inodes index feature");
static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT);
module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644);
-MODULE_PARM_DESC(ovl_nfs_export_def,
+MODULE_PARM_DESC(nfs_export,
"Default to on or off for the NFS export feature");
static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO);
module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644);
-MODULE_PARM_DESC(ovl_xino_auto_def,
+MODULE_PARM_DESC(xino_auto,
"Auto enable xino feature");
static void ovl_entry_stack_free(struct ovl_entry *oe)
@@ -66,7 +63,7 @@ static void ovl_entry_stack_free(struct ovl_entry *oe)
static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY);
module_param_named(metacopy, ovl_metacopy_def, bool, 0644);
-MODULE_PARM_DESC(ovl_metacopy_def,
+MODULE_PARM_DESC(metacopy,
"Default to on or off for the metadata only copy up feature");
static void ovl_dentry_release(struct dentry *dentry)
@@ -215,6 +212,9 @@ static void ovl_free_fs(struct ovl_fs *ofs)
{
unsigned i;
+ iput(ofs->indexdir_trap);
+ iput(ofs->workdir_trap);
+ iput(ofs->upperdir_trap);
dput(ofs->indexdir);
dput(ofs->workdir);
if (ofs->workdir_locked)
@@ -223,8 +223,10 @@ static void ovl_free_fs(struct ovl_fs *ofs)
if (ofs->upperdir_locked)
ovl_inuse_unlock(ofs->upper_mnt->mnt_root);
mntput(ofs->upper_mnt);
- for (i = 0; i < ofs->numlower; i++)
+ for (i = 0; i < ofs->numlower; i++) {
+ iput(ofs->lower_layers[i].trap);
mntput(ofs->lower_layers[i].mnt);
+ }
for (i = 0; i < ofs->numlowerfs; i++)
free_anon_bdev(ofs->lower_fs[i].pseudo_dev);
kfree(ofs->lower_layers);
@@ -983,7 +985,26 @@ static const struct xattr_handler *ovl_xattr_handlers[] = {
NULL
};
-static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath)
+static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
+ struct inode **ptrap, const char *name)
+{
+ struct inode *trap;
+ int err;
+
+ trap = ovl_get_trap_inode(sb, dir);
+ err = PTR_ERR_OR_ZERO(trap);
+ if (err) {
+ if (err == -ELOOP)
+ pr_err("overlayfs: conflicting %s path\n", name);
+ return err;
+ }
+
+ *ptrap = trap;
+ return 0;
+}
+
+static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
+ struct path *upperpath)
{
struct vfsmount *upper_mnt;
int err;
@@ -1003,6 +1024,11 @@ static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath)
if (err)
goto out;
+ err = ovl_setup_trap(sb, upperpath->dentry, &ofs->upperdir_trap,
+ "upperdir");
+ if (err)
+ goto out;
+
upper_mnt = clone_private_mount(upperpath);
err = PTR_ERR(upper_mnt);
if (IS_ERR(upper_mnt)) {
@@ -1029,7 +1055,8 @@ out:
return err;
}
-static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
+static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
+ struct path *workpath)
{
struct vfsmount *mnt = ofs->upper_mnt;
struct dentry *temp;
@@ -1044,6 +1071,10 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)
if (!ofs->workdir)
goto out;
+ err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir");
+ if (err)
+ goto out;
+
/*
* Upper should support d_type, else whiteouts are visible. Given
* workdir and upper are on same fs, we can do iterate_dir() on
@@ -1104,7 +1135,8 @@ out:
return err;
}
-static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
+static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
+ struct path *upperpath)
{
int err;
struct path workpath = { };
@@ -1135,19 +1167,16 @@ static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
}
- err = ovl_make_workdir(ofs, &workpath);
- if (err)
- goto out;
+ err = ovl_make_workdir(sb, ofs, &workpath);
- err = 0;
out:
path_put(&workpath);
return err;
}
-static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
- struct path *upperpath)
+static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
+ struct ovl_entry *oe, struct path *upperpath)
{
struct vfsmount *mnt = ofs->upper_mnt;
int err;
@@ -1166,6 +1195,11 @@ static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,
ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
if (ofs->indexdir) {
+ err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
+ "indexdir");
+ if (err)
+ goto out;
+
/*
* Verify upper root is exclusively associated with index dir.
* Older kernels stored upper fh in "trusted.overlay.origin"
@@ -1253,8 +1287,8 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
return ofs->numlowerfs;
}
-static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack,
- unsigned int numlower)
+static int ovl_get_lower_layers(struct super_block *sb, struct ovl_fs *ofs,
+ struct path *stack, unsigned int numlower)
{
int err;
unsigned int i;
@@ -1272,16 +1306,28 @@ static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack,
for (i = 0; i < numlower; i++) {
struct vfsmount *mnt;
+ struct inode *trap;
int fsid;
err = fsid = ovl_get_fsid(ofs, &stack[i]);
if (err < 0)
goto out;
+ err = -EBUSY;
+ if (ovl_is_inuse(stack[i].dentry)) {
+ pr_err("overlayfs: lowerdir is in-use as upperdir/workdir\n");
+ goto out;
+ }
+
+ err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir");
+ if (err)
+ goto out;
+
mnt = clone_private_mount(&stack[i]);
err = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
pr_err("overlayfs: failed to clone lowerpath\n");
+ iput(trap);
goto out;
}
@@ -1291,6 +1337,7 @@ static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack,
*/
mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
+ ofs->lower_layers[ofs->numlower].trap = trap;
ofs->lower_layers[ofs->numlower].mnt = mnt;
ofs->lower_layers[ofs->numlower].idx = i + 1;
ofs->lower_layers[ofs->numlower].fsid = fsid;
@@ -1385,7 +1432,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
goto out_err;
}
- err = ovl_get_lower_layers(ofs, stack, numlower);
+ err = ovl_get_lower_layers(sb, ofs, stack, numlower);
if (err)
goto out_err;
@@ -1417,6 +1464,77 @@ out_err:
goto out;
}
+/*
+ * Check if this layer root is a descendant of:
+ * - another layer of this overlayfs instance
+ * - upper/work dir of any overlayfs instance
+ */
+static int ovl_check_layer(struct super_block *sb, struct dentry *dentry,
+ const char *name)
+{
+ struct dentry *next = dentry, *parent;
+ int err = 0;
+
+ if (!dentry)
+ return 0;
+
+ parent = dget_parent(next);
+
+ /* Walk back ancestors to root (inclusive) looking for traps */
+ while (!err && parent != next) {
+ if (ovl_is_inuse(parent)) {
+ err = -EBUSY;
+ pr_err("overlayfs: %s path overlapping in-use upperdir/workdir\n",
+ name);
+ } else if (ovl_lookup_trap_inode(sb, parent)) {
+ err = -ELOOP;
+ pr_err("overlayfs: overlapping %s path\n", name);
+ }
+ next = parent;
+ parent = dget_parent(next);
+ dput(next);
+ }
+
+ dput(parent);
+
+ return err;
+}
+
+/*
+ * Check if any of the layers or work dirs overlap.
+ */
+static int ovl_check_overlapping_layers(struct super_block *sb,
+ struct ovl_fs *ofs)
+{
+ int i, err;
+
+ if (ofs->upper_mnt) {
+ err = ovl_check_layer(sb, ofs->upper_mnt->mnt_root, "upperdir");
+ if (err)
+ return err;
+
+ /*
+ * Checking workbasedir avoids hitting ovl_is_inuse(parent) of
+ * this instance and covers overlapping work and index dirs,
+ * unless work or index dir have been moved since created inside
+ * workbasedir. In that case, we already have their traps in
+ * inode cache and we will catch that case on lookup.
+ */
+ err = ovl_check_layer(sb, ofs->workbasedir, "workdir");
+ if (err)
+ return err;
+ }
+
+ for (i = 0; i < ofs->numlower; i++) {
+ err = ovl_check_layer(sb, ofs->lower_layers[i].mnt->mnt_root,
+ "lowerdir");
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
{
struct path upperpath = { };
@@ -1456,17 +1574,20 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (ofs->config.xino != OVL_XINO_OFF)
ofs->xino_bits = BITS_PER_LONG - 32;
+ /* alloc/destroy_inode needed for setting up traps in inode cache */
+ sb->s_op = &ovl_super_operations;
+
if (ofs->config.upperdir) {
if (!ofs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
goto out_err;
}
- err = ovl_get_upper(ofs, &upperpath);
+ err = ovl_get_upper(sb, ofs, &upperpath);
if (err)
goto out_err;
- err = ovl_get_workdir(ofs, &upperpath);
+ err = ovl_get_workdir(sb, ofs, &upperpath);
if (err)
goto out_err;
@@ -1487,7 +1608,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_flags |= SB_RDONLY;
if (!(ovl_force_readonly(ofs)) && ofs->config.index) {
- err = ovl_get_indexdir(ofs, oe, &upperpath);
+ err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
if (err)
goto out_free_oe;
@@ -1500,6 +1621,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
}
+ err = ovl_check_overlapping_layers(sb, ofs);
+ if (err)
+ goto out_free_oe;
+
/* Show index=off in /proc/mounts for forced r/o mount */
if (!ofs->indexdir) {
ofs->config.index = false;
@@ -1521,7 +1646,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
- sb->s_op = &ovl_super_operations;
sb->s_xattr = ovl_xattr_handlers;
sb->s_fs_info = ofs;
sb->s_flags |= SB_POSIXACL;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 4035e640f402..f5678a3f8350 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Novell Inc.
* Copyright (C) 2016 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
*/
#include <linux/fs.h>
@@ -652,6 +649,18 @@ void ovl_inuse_unlock(struct dentry *dentry)
}
}
+bool ovl_is_inuse(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ bool inuse;
+
+ spin_lock(&inode->i_lock);
+ inuse = (inode->i_state & I_OVL_INUSE);
+ spin_unlock(&inode->i_lock);
+
+ return inuse;
+}
+
/*
* Does this overlay dentry need to be indexed on copy up?
*/
generated by cgit v1.2.3 (git 2.39.0) at 2025-03-05 19:20:44 +0300