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-rw-r--r--Documentation/filesystems/overlayfs.rst36
-rw-r--r--fs/overlayfs/copy_up.c28
-rw-r--r--fs/overlayfs/export.c10
-rw-r--r--fs/overlayfs/file.c144
-rw-r--r--fs/overlayfs/inode.c14
-rw-r--r--fs/overlayfs/namei.c28
-rw-r--r--fs/overlayfs/overlayfs.h22
-rw-r--r--fs/overlayfs/ovl_entry.h2
-rw-r--r--fs/overlayfs/super.c95
-rw-r--r--fs/overlayfs/util.c18
-rw-r--r--fs/remap_range.c10
-rw-r--r--fs/xattr.c17
-rw-r--r--include/linux/capability.h2
-rw-r--r--security/commoncap.c3
14 files changed, 233 insertions, 196 deletions
diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
index 580ab9a0fe31..587a93973929 100644
--- a/Documentation/filesystems/overlayfs.rst
+++ b/Documentation/filesystems/overlayfs.rst
@@ -97,11 +97,13 @@ directory trees to be in the same filesystem and there is no
requirement that the root of a filesystem be given for either upper or
lower.
-The lower filesystem can be any filesystem supported by Linux and does
-not need to be writable. The lower filesystem can even be another
-overlayfs. The upper filesystem will normally be writable and if it
-is it must support the creation of trusted.* extended attributes, and
-must provide valid d_type in readdir responses, so NFS is not suitable.
+A wide range of filesystems supported by Linux can be the lower filesystem,
+but not all filesystems that are mountable by Linux have the features
+needed for OverlayFS to work. The lower filesystem does not need to be
+writable. The lower filesystem can even be another overlayfs. The upper
+filesystem will normally be writable and if it is it must support the
+creation of trusted.* and/or user.* extended attributes, and must provide
+valid d_type in readdir responses, so NFS is not suitable.
A read-only overlay of two read-only filesystems may use any
filesystem type.
@@ -467,14 +469,18 @@ summarized in the `Inode properties`_ table above.
Changes to underlying filesystems
---------------------------------
-Offline changes, when the overlay is not mounted, are allowed to either
-the upper or the lower trees.
-
Changes to the underlying filesystems while part of a mounted overlay
filesystem are not allowed. If the underlying filesystem is changed,
the behavior of the overlay is undefined, though it will not result in
a crash or deadlock.
+Offline changes, when the overlay is not mounted, are allowed to the
+upper tree. Offline changes to the lower tree are only allowed if the
+"metadata only copy up", "inode index", and "redirect_dir" features
+have not been used. If the lower tree is modified and any of these
+features has been used, the behavior of the overlay is undefined,
+though it will not result in a crash or deadlock.
+
When the overlay NFS export feature is enabled, overlay filesystems
behavior on offline changes of the underlying lower layer is different
than the behavior when NFS export is disabled.
@@ -563,6 +569,11 @@ This verification may cause significant overhead in some cases.
Note: the mount options index=off,nfs_export=on are conflicting for a
read-write mount and will result in an error.
+Note: the mount option uuid=off can be used to replace UUID of the underlying
+filesystem in file handles with null, and effectively disable UUID checks. This
+can be useful in case the underlying disk is copied and the UUID of this copy
+is changed. This is only applicable if all lower/upper/work directories are on
+the same filesystem, otherwise it will fallback to normal behaviour.
Volatile mount
--------------
@@ -583,6 +594,15 @@ fresh one. In very limited cases where the user knows that the system has
not crashed and contents of upperdir are intact, The "volatile" directory
can be removed.
+
+User xattr
+----------
+
+The the "-o userxattr" mount option forces overlayfs to use the
+"user.overlay." xattr namespace instead of "trusted.overlay.". This is
+useful for unprivileged mounting of overlayfs.
+
+
Testsuite
---------
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 955ecd4030f0..e5b616c93e11 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -275,7 +275,8 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
return err;
}
-struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
+struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
+ bool is_upper)
{
struct ovl_fh *fh;
int fh_type, dwords;
@@ -319,7 +320,8 @@ struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
if (is_upper)
fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
fh->fb.len = sizeof(fh->fb) + buflen;
- fh->fb.uuid = *uuid;
+ if (ofs->config.uuid)
+ fh->fb.uuid = *uuid;
return fh;
@@ -328,8 +330,8 @@ out_err:
return ERR_PTR(err);
}
-int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
- struct dentry *upper)
+int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry,
+ struct dentry *lower, struct dentry *upper)
{
const struct ovl_fh *fh = NULL;
int err;
@@ -340,7 +342,7 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
* up and a pure upper inode.
*/
if (ovl_can_decode_fh(lower->d_sb)) {
- fh = ovl_encode_real_fh(lower, false);
+ fh = ovl_encode_real_fh(ofs, lower, false);
if (IS_ERR(fh))
return PTR_ERR(fh);
}
@@ -352,7 +354,8 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
fh ? fh->fb.len : 0, 0);
kfree(fh);
- return err;
+ /* Ignore -EPERM from setting "user.*" on symlink/special */
+ return err == -EPERM ? 0 : err;
}
/* Store file handle of @upper dir in @index dir entry */
@@ -362,7 +365,7 @@ static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
const struct ovl_fh *fh;
int err;
- fh = ovl_encode_real_fh(upper, true);
+ fh = ovl_encode_real_fh(ofs, upper, true);
if (IS_ERR(fh))
return PTR_ERR(fh);
@@ -380,6 +383,7 @@ static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
struct dentry *upper)
{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
struct inode *dir = d_inode(indexdir);
struct dentry *index = NULL;
@@ -402,7 +406,7 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
return -EIO;
- err = ovl_get_index_name(origin, &name);
+ err = ovl_get_index_name(ofs, origin, &name);
if (err)
return err;
@@ -411,7 +415,7 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
if (IS_ERR(temp))
goto free_name;
- err = ovl_set_upper_fh(OVL_FS(dentry->d_sb), upper, temp);
+ err = ovl_set_upper_fh(ofs, upper, temp);
if (err)
goto out;
@@ -521,7 +525,7 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
* hard link.
*/
if (c->origin) {
- err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp);
+ err = ovl_set_origin(ofs, c->dentry, c->lowerpath.dentry, temp);
if (err)
return err;
}
@@ -700,7 +704,7 @@ out_dput:
static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
{
int err;
- struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
bool to_index = false;
/*
@@ -722,7 +726,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
if (to_index) {
c->destdir = ovl_indexdir(c->dentry->d_sb);
- err = ovl_get_index_name(c->lowerpath.dentry, &c->destname);
+ err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
if (err)
return err;
} else if (WARN_ON(!c->parent)) {
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index ed35be3fafc6..41ebf52f1bbc 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -211,7 +211,8 @@ static int ovl_check_encode_origin(struct dentry *dentry)
return 1;
}
-static int ovl_dentry_to_fid(struct dentry *dentry, u32 *fid, int buflen)
+static int ovl_dentry_to_fid(struct ovl_fs *ofs, struct dentry *dentry,
+ u32 *fid, int buflen)
{
struct ovl_fh *fh = NULL;
int err, enc_lower;
@@ -226,7 +227,7 @@ static int ovl_dentry_to_fid(struct dentry *dentry, u32 *fid, int buflen)
goto fail;
/* Encode an upper or lower file handle */
- fh = ovl_encode_real_fh(enc_lower ? ovl_dentry_lower(dentry) :
+ fh = ovl_encode_real_fh(ofs, enc_lower ? ovl_dentry_lower(dentry) :
ovl_dentry_upper(dentry), !enc_lower);
if (IS_ERR(fh))
return PTR_ERR(fh);
@@ -249,6 +250,7 @@ fail:
static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
struct inode *parent)
{
+ struct ovl_fs *ofs = OVL_FS(inode->i_sb);
struct dentry *dentry;
int bytes, buflen = *max_len << 2;
@@ -260,7 +262,7 @@ static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
if (WARN_ON(!dentry))
return FILEID_INVALID;
- bytes = ovl_dentry_to_fid(dentry, fid, buflen);
+ bytes = ovl_dentry_to_fid(ofs, dentry, fid, buflen);
dput(dentry);
if (bytes <= 0)
return FILEID_INVALID;
@@ -680,7 +682,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
if (!ovl_upper_mnt(ofs))
return ERR_PTR(-EACCES);
- upper = ovl_decode_real_fh(fh, ovl_upper_mnt(ofs), true);
+ upper = ovl_decode_real_fh(ofs, fh, ovl_upper_mnt(ofs), true);
if (IS_ERR_OR_NULL(upper))
return upper;
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index efccb7c1f9bc..bd9dd38347ae 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -53,9 +53,10 @@ static struct file *ovl_open_realfile(const struct file *file,
err = inode_permission(realinode, MAY_OPEN | acc_mode);
if (err) {
realfile = ERR_PTR(err);
- } else if (!inode_owner_or_capable(realinode)) {
- realfile = ERR_PTR(-EPERM);
} else {
+ if (!inode_owner_or_capable(realinode))
+ flags &= ~O_NOATIME;
+
realfile = open_with_fake_path(&file->f_path, flags, realinode,
current_cred());
}
@@ -75,12 +76,6 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
struct inode *inode = file_inode(file);
int err;
- flags |= OVL_OPEN_FLAGS;
-
- /* If some flag changed that cannot be changed then something's amiss */
- if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
- return -EIO;
-
flags &= OVL_SETFL_MASK;
if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
@@ -397,48 +392,6 @@ out_unlock:
return ret;
}
-static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe, size_t len,
- unsigned int flags)
-{
- ssize_t ret;
- struct fd real;
- const struct cred *old_cred;
-
- ret = ovl_real_fdget(in, &real);
- if (ret)
- return ret;
-
- old_cred = ovl_override_creds(file_inode(in)->i_sb);
- ret = generic_file_splice_read(real.file, ppos, pipe, len, flags);
- revert_creds(old_cred);
-
- ovl_file_accessed(in);
- fdput(real);
- return ret;
-}
-
-static ssize_t
-ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
- loff_t *ppos, size_t len, unsigned int flags)
-{
- struct fd real;
- const struct cred *old_cred;
- ssize_t ret;
-
- ret = ovl_real_fdget(out, &real);
- if (ret)
- return ret;
-
- old_cred = ovl_override_creds(file_inode(out)->i_sb);
- ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
- revert_creds(old_cred);
-
- ovl_file_accessed(out);
- fdput(real);
- return ret;
-}
-
static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct fd real;
@@ -541,46 +494,31 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct fd real;
- const struct cred *old_cred;
long ret;
ret = ovl_real_fdget(file, &real);
if (ret)
return ret;
- old_cred = ovl_override_creds(file_inode(file)->i_sb);
ret = security_file_ioctl(real.file, cmd, arg);
- if (!ret)
+ if (!ret) {
+ /*
+ * Don't override creds, since we currently can't safely check
+ * permissions before doing so.
+ */
ret = vfs_ioctl(real.file, cmd, arg);
- revert_creds(old_cred);
+ }
fdput(real);
return ret;
}
-static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)
-{
- unsigned int flags = 0;
-
- if (iflags & S_SYNC)
- flags |= FS_SYNC_FL;
- if (iflags & S_APPEND)
- flags |= FS_APPEND_FL;
- if (iflags & S_IMMUTABLE)
- flags |= FS_IMMUTABLE_FL;
- if (iflags & S_NOATIME)
- flags |= FS_NOATIME_FL;
-
- return flags;
-}
-
static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
- unsigned long arg, unsigned int flags)
+ unsigned long arg)
{
long ret;
struct inode *inode = file_inode(file);
- unsigned int oldflags;
if (!inode_owner_or_capable(inode))
return -EACCES;
@@ -591,10 +529,13 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
inode_lock(inode);
- /* Check the capability before cred override */
- oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));
- ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
- if (ret)
+ /*
+ * Prevent copy up if immutable and has no CAP_LINUX_IMMUTABLE
+ * capability.
+ */
+ ret = -EPERM;
+ if (!ovl_has_upperdata(inode) && IS_IMMUTABLE(inode) &&
+ !capable(CAP_LINUX_IMMUTABLE))
goto unlock;
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@@ -613,46 +554,6 @@ unlock:
}
-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, flags);
-}
-
-static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)
-{
- unsigned int flags = 0;
-
- if (xflags & FS_XFLAG_SYNC)
- flags |= FS_SYNC_FL;
- if (xflags & FS_XFLAG_APPEND)
- flags |= FS_APPEND_FL;
- if (xflags & FS_XFLAG_IMMUTABLE)
- flags |= FS_IMMUTABLE_FL;
- if (xflags & FS_XFLAG_NOATIME)
- flags |= FS_NOATIME_FL;
-
- return flags;
-}
-
-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_fsflags(fa.fsx_xflags));
-}
-
long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;
@@ -663,12 +564,9 @@ long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
ret = ovl_real_ioctl(file, cmd, arg);
break;
- case FS_IOC_SETFLAGS:
- ret = ovl_ioctl_set_fsflags(file, cmd, arg);
- break;
-
case FS_IOC_FSSETXATTR:
- ret = ovl_ioctl_set_fsxflags(file, cmd, arg);
+ case FS_IOC_SETFLAGS:
+ ret = ovl_ioctl_set_flags(file, cmd, arg);
break;
default:
@@ -801,8 +699,8 @@ const struct file_operations ovl_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ovl_compat_ioctl,
#endif
- .splice_read = ovl_splice_read,
- .splice_write = ovl_splice_write,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
.copy_file_range = ovl_copy_file_range,
.remap_file_range = ovl_remap_file_range,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b584dca845ba..d739e14c6814 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -329,8 +329,14 @@ static const char *ovl_get_link(struct dentry *dentry,
bool ovl_is_private_xattr(struct super_block *sb, const char *name)
{
- return strncmp(name, OVL_XATTR_PREFIX,
- sizeof(OVL_XATTR_PREFIX) - 1) == 0;
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ if (ofs->config.userxattr)
+ return strncmp(name, OVL_XATTR_USER_PREFIX,
+ sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0;
+ else
+ return strncmp(name, OVL_XATTR_TRUSTED_PREFIX,
+ sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0;
}
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
@@ -476,7 +482,7 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
int err;
- struct inode *realinode = ovl_inode_real(inode);
+ struct inode *realinode = ovl_inode_realdata(inode);
const struct cred *old_cred;
if (!realinode->i_op->fiemap)
@@ -690,7 +696,7 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev)
* For the first, copy up case, the union nlink does not change, whether the
* operation succeeds or fails, but the upper inode nlink may change.
* Therefore, before copy up, we store the union nlink value relative to the
- * lower inode nlink in the index inode xattr trusted.overlay.nlink.
+ * lower inode nlink in the index inode xattr .overlay.nlink.
*
* For the second, upper hardlink case, the union nlink should be incremented
* or decremented IFF the operation succeeds, aligned with nlink change of the
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index a6162c4076db..3fe05fb5d145 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -150,17 +150,22 @@ invalid:
goto out;
}
-struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
- bool connected)
+struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
+ struct vfsmount *mnt, bool connected)
{
struct dentry *real;
int bytes;
+ if (!capable(CAP_DAC_READ_SEARCH))
+ return NULL;
+
/*
* Make sure that the stored uuid matches the uuid of the lower
* layer where file handle will be decoded.
+ * In case of uuid=off option just make sure that stored uuid is null.
*/
- if (!uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid))
+ if (ofs->config.uuid ? !uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid) :
+ !uuid_is_null(&fh->fb.uuid))
return NULL;
bytes = (fh->fb.len - offsetof(struct ovl_fb, fid));
@@ -354,7 +359,7 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
ofs->layers[i].fs->bad_uuid)
continue;
- origin = ovl_decode_real_fh(fh, ofs->layers[i].mnt,
+ origin = ovl_decode_real_fh(ofs, fh, ofs->layers[i].mnt,
connected);
if (origin)
break;
@@ -450,7 +455,7 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
struct ovl_fh *fh;
int err;
- fh = ovl_encode_real_fh(real, is_upper);
+ fh = ovl_encode_real_fh(ofs, real, is_upper);
err = PTR_ERR(fh);
if (IS_ERR(fh)) {
fh = NULL;
@@ -488,7 +493,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
if (IS_ERR_OR_NULL(fh))
return ERR_CAST(fh);
- upper = ovl_decode_real_fh(fh, ovl_upper_mnt(ofs), true);
+ upper = ovl_decode_real_fh(ofs, fh, ovl_upper_mnt(ofs), true);
kfree(fh);
if (IS_ERR_OR_NULL(upper))
@@ -640,12 +645,13 @@ static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name)
* index dir was cleared. Either way, that index cannot be used to indentify
* the overlay inode.
*/
-int ovl_get_index_name(struct dentry *origin, struct qstr *name)
+int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
+ struct qstr *name)
{
struct ovl_fh *fh;
int err;
- fh = ovl_encode_real_fh(origin, false);
+ fh = ovl_encode_real_fh(ofs, origin, false);
if (IS_ERR(fh))
return PTR_ERR(fh);
@@ -694,7 +700,7 @@ struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
bool is_dir = d_is_dir(origin);
int err;
- err = ovl_get_index_name(origin, &name);
+ err = ovl_get_index_name(ofs, origin, &name);
if (err)
return ERR_PTR(err);
@@ -805,7 +811,7 @@ static int ovl_fix_origin(struct ovl_fs *ofs, struct dentry *dentry,
if (err)
return err;
- err = ovl_set_origin(dentry, lower, upper);
+ err = ovl_set_origin(ofs, dentry, lower, upper);
if (!err)
err = ovl_set_impure(dentry->d_parent, upper->d_parent);
@@ -1003,6 +1009,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* Just make sure a corresponding data dentry has been found.
*/
if (d.metacopy || (uppermetacopy && !ctr)) {
+ pr_warn_ratelimited("metacopy with no lower data found - abort lookup (%pd2)\n",
+ dentry);
err = -EIO;
goto out_put;
} else if (!d.is_dir && upperdentry && !ctr && origin_path) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index f8880aa2ba0e..b487e48c7fd4 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -22,7 +22,9 @@ enum ovl_path_type {
#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
#define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
-#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
+#define OVL_XATTR_NAMESPACE "overlay."
+#define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
+#define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
enum ovl_xattr {
OVL_XATTR_OPAQUE,
@@ -113,10 +115,10 @@ struct ovl_fh {
#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
offsetof(struct ovl_fb, fid))
-extern const char *ovl_xattr_table[];
+extern const char *const ovl_xattr_table[][2];
static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
{
- return ovl_xattr_table[ox];
+ return ovl_xattr_table[ox][ofs->config.userxattr];
}
static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
@@ -383,8 +385,8 @@ static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
}
-struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
- bool connected);
+struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
+ struct vfsmount *mnt, bool connected);
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
struct dentry *upperdentry, struct ovl_path **stackp);
int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
@@ -392,7 +394,8 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
bool set);
struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
-int ovl_get_index_name(struct dentry *origin, struct qstr *name);
+int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
+ struct qstr *name);
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
struct dentry *origin, bool verify);
@@ -514,9 +517,10 @@ int ovl_maybe_copy_up(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
-struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
-int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
- struct dentry *upper);
+struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
+ bool is_upper);
+int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry,
+ struct dentry *lower, struct dentry *upper);
/* export.c */
extern const struct export_operations ovl_export_operations;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 1b5a2094df8e..fbd5e27ce66b 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -14,9 +14,11 @@ struct ovl_config {
bool redirect_follow;
const char *redirect_mode;
bool index;
+ bool uuid;
bool nfs_export;
int xino;
bool metacopy;
+ bool userxattr;
bool ovl_volatile;
};
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 290983bcfbb3..2bd570cbe8a4 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -79,7 +79,7 @@ static void ovl_dentry_release(struct dentry *dentry)
static struct dentry *ovl_d_real(struct dentry *dentry,
const struct inode *inode)
{
- struct dentry *real;
+ struct dentry *real = NULL, *lower;
/* It's an overlay file */
if (inode && d_inode(dentry) == inode)
@@ -98,9 +98,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
if (real && !inode && ovl_has_upperdata(d_inode(dentry)))
return real;
- real = ovl_dentry_lowerdata(dentry);
- if (!real)
+ lower = ovl_dentry_lowerdata(dentry);
+ if (!lower)
goto bug;
+ real = lower;
/* Handle recursion */
real = d_real(real, inode);
@@ -108,8 +109,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
if (!inode || inode == d_inode(real))
return real;
bug:
- WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
- inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
+ WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n",
+ __func__, dentry, inode ? inode->i_sb->s_id : "NULL",
+ inode ? inode->i_ino : 0, real,
+ real && d_inode(real) ? d_inode(real)->i_ino : 0);
return dentry;
}
@@ -356,6 +359,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode);
if (ofs->config.index != ovl_index_def)
seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
+ if (!ofs->config.uuid)
+ seq_puts(m, ",uuid=off");
if (ofs->config.nfs_export != ovl_nfs_export_def)
seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
"on" : "off");
@@ -410,7 +415,10 @@ enum {
OPT_REDIRECT_DIR,
OPT_INDEX_ON,
OPT_INDEX_OFF,
+ OPT_UUID_ON,
+ OPT_UUID_OFF,
OPT_NFS_EXPORT_ON,
+ OPT_USERXATTR,
OPT_NFS_EXPORT_OFF,
OPT_XINO_ON,
OPT_XINO_OFF,
@@ -429,6 +437,9 @@ static const match_table_t ovl_tokens = {
{OPT_REDIRECT_DIR, "redirect_dir=%s"},
{OPT_INDEX_ON, "index=on"},
{OPT_INDEX_OFF, "index=off"},
+ {OPT_USERXATTR, "userxattr"},
+ {OPT_UUID_ON, "uuid=on"},
+ {OPT_UUID_OFF, "uuid=off"},
{OPT_NFS_EXPORT_ON, "nfs_export=on"},
{OPT_NFS_EXPORT_OFF, "nfs_export=off"},
{OPT_XINO_ON, "xino=on"},
@@ -549,6 +560,14 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
index_opt = true;
break;
+ case OPT_UUID_ON:
+ config->uuid = true;
+ break;
+
+ case OPT_UUID_OFF:
+ config->uuid = false;
+ break;
+
case OPT_NFS_EXPORT_ON:
config->nfs_export = true;
nfs_export_opt = true;
@@ -585,6 +604,10 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
config->ovl_volatile = true;
break;
+ case OPT_USERXATTR:
+ config->userxattr = true;
+ break;
+
default:
pr_err("unrecognized mount option \"%s\" or missing value\n",
p);
@@ -688,6 +711,28 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
}
}
+
+ /* Resolve userxattr -> !redirect && !metacopy dependency */
+ if (config->userxattr) {
+ if (config->redirect_follow && redirect_opt) {
+ pr_err("conflicting options: userxattr,redirect_dir=%s\n",
+ config->redirect_mode);
+ return -EINVAL;
+ }
+ if (config->metacopy && metacopy_opt) {
+ pr_err("conflicting options: userxattr,metacopy=on\n");
+ return -EINVAL;
+ }
+ /*
+ * Silently disable default setting of redirect and metacopy.
+ * This shall be the default in the future as well: these
+ * options must be explicitly enabled if used together with
+ * userxattr.
+ */
+ config->redirect_dir = config->redirect_follow = false;
+ config->metacopy = false;
+ }
+
return 0;
}
@@ -1037,8 +1082,14 @@ ovl_posix_acl_default_xattr_handler = {
.set = ovl_posix_acl_xattr_set,
};
-static const struct xattr_handler ovl_own_xattr_handler = {
- .prefix = OVL_XATTR_PREFIX,
+static const struct xattr_handler ovl_own_trusted_xattr_handler = {
+ .prefix = OVL_XATTR_TRUSTED_PREFIX,
+ .get = ovl_own_xattr_get,
+ .set = ovl_own_xattr_set,
+};
+
+static const struct xattr_handler ovl_own_user_xattr_handler = {
+ .prefix = OVL_XATTR_USER_PREFIX,
.get = ovl_own_xattr_get,
.set = ovl_own_xattr_set,
};
@@ -1049,12 +1100,22 @@ static const struct xattr_handler ovl_other_xattr_handler = {
.set = ovl_other_xattr_set,
};
-static const struct xattr_handler *ovl_xattr_handlers[] = {
+static const struct xattr_handler *ovl_trusted_xattr_handlers[] = {
#ifdef CONFIG_FS_POSIX_ACL
&ovl_posix_acl_access_xattr_handler,
&ovl_posix_acl_default_xattr_handler,
#endif
- &ovl_own_xattr_handler,
+ &ovl_own_trusted_xattr_handler,
+ &ovl_other_xattr_handler,
+ NULL
+};
+
+static const struct xattr_handler *ovl_user_xattr_handlers[] = {
+#ifdef CONFIG_FS_POSIX_ACL
+ &ovl_posix_acl_access_xattr_handler,
+ &ovl_posix_acl_default_xattr_handler,
+#endif
+ &ovl_own_user_xattr_handler,
&ovl_other_xattr_handler,
NULL
};
@@ -1317,7 +1378,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
pr_warn("upper fs does not support RENAME_WHITEOUT.\n");
/*
- * Check if upper/work fs supports trusted.overlay.* xattr
+ * Check if upper/work fs supports (trusted|user).overlay.* xattr
*/
err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
if (err) {
@@ -1456,10 +1517,10 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
/*
* Verify upper root is exclusively associated with index dir.
- * Older kernels stored upper fh in "trusted.overlay.origin"
+ * Older kernels stored upper fh in ".overlay.origin"
* xattr. If that xattr exists, verify that it is a match to
* upper dir file handle. In any case, verify or set xattr
- * "trusted.overlay.upper" to indicate that index may have
+ * ".overlay.upper" to indicate that index may have
* directory entries.
*/
if (ovl_check_origin_xattr(ofs, ofs->indexdir)) {
@@ -1877,6 +1938,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ofs->share_whiteout = true;
ofs->config.index = ovl_index_def;
+ ofs->config.uuid = true;
ofs->config.nfs_export = ovl_nfs_export_def;
ofs->config.xino = ovl_xino_def();
ofs->config.metacopy = ovl_metacopy_def;
@@ -1956,6 +2018,11 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!ovl_upper_mnt(ofs))
sb->s_flags |= SB_RDONLY;
+ if (!ofs->config.uuid && ofs->numfs > 1) {
+ pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n");
+ ofs->config.uuid = true;
+ }
+
if (!ovl_force_readonly(ofs) && ofs->config.index) {
err = ovl_get_indexdir(sb, ofs, oe, &upperpath);
if (err)
@@ -1991,7 +2058,8 @@ 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_xattr = ovl_xattr_handlers;
+ sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :
+ ovl_trusted_xattr_handlers;
sb->s_fs_info = ofs;
sb->s_flags |= SB_POSIXACL;
sb->s_iflags |= SB_I_SKIP_SYNC;
@@ -2028,6 +2096,7 @@ static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
static struct file_system_type ovl_fs_type = {
.owner = THIS_MODULE,
.name = "overlay",
+ .fs_flags = FS_USERNS_MOUNT,
.mount = ovl_mount,
.kill_sb = kill_anon_super,
};
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 23f475627d07..6569031af3cd 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -50,6 +50,9 @@ const struct cred *ovl_override_creds(struct super_block *sb)
*/
int ovl_can_decode_fh(struct super_block *sb)
{
+ if (!capable(CAP_DAC_READ_SEARCH))
+ return 0;
+
if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)
return 0;
@@ -582,9 +585,10 @@ bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
#define OVL_XATTR_METACOPY_POSTFIX "metacopy"
#define OVL_XATTR_TAB_ENTRY(x) \
- [x] = OVL_XATTR_PREFIX x ## _POSTFIX
+ [x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \
+ [true] = OVL_XATTR_USER_PREFIX x ## _POSTFIX }
-const char *ovl_xattr_table[] = {
+const char *const ovl_xattr_table[][2] = {
OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT),
OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN),
@@ -716,6 +720,7 @@ bool ovl_need_index(struct dentry *dentry)
/* Caller must hold OVL_I(inode)->lock */
static void ovl_cleanup_index(struct dentry *dentry)
{
+ struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
struct inode *dir = indexdir->d_inode;
struct dentry *lowerdentry = ovl_dentry_lower(dentry);
@@ -725,7 +730,7 @@ static void ovl_cleanup_index(struct dentry *dentry)
struct qstr name = { };
int err;
- err = ovl_get_index_name(lowerdentry, &name);
+ err = ovl_get_index_name(ofs, lowerdentry, &name);
if (err)
goto fail;
@@ -879,6 +884,13 @@ int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry)
if (res < 0) {
if (res == -ENODATA || res == -EOPNOTSUPP)
return 0;
+ /*
+ * getxattr on user.* may fail with EACCES in case there's no
+ * read permission on the inode. Not much we can do, other than
+ * tell the caller that this is not a metacopy inode.
+ */
+ if (ofs->config.userxattr && res == -EACCES)
+ return 0;
goto out;
}
diff --git a/fs/remap_range.c b/fs/remap_range.c
index e6099beefa97..77dba3a49e65 100644
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -456,8 +456,16 @@ loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
if (ret)
return ret;
+ /*
+ * This is redundant if called from vfs_dedupe_file_range(), but other
+ * callers need it and it's not performance sesitive...
+ */
+ ret = remap_verify_area(src_file, src_pos, len, false);
+ if (ret)
+ goto out_drop_write;
+
ret = remap_verify_area(dst_file, dst_pos, len, true);
- if (ret < 0)
+ if (ret)
goto out_drop_write;
ret = -EPERM;
diff --git a/fs/xattr.c b/fs/xattr.c
index cd7a563e8bcd..fd57153b1f61 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -276,8 +276,16 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
{
struct inode *inode = dentry->d_inode;
struct inode *delegated_inode = NULL;
+ const void *orig_value = value;
int error;
+ if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
+ error = cap_convert_nscap(dentry, &value, size);
+ if (error < 0)
+ return error;
+ size = error;
+ }
+
retry_deleg:
inode_lock(inode);
error = __vfs_setxattr_locked(dentry, name, value, size, flags,
@@ -289,6 +297,9 @@ retry_deleg:
if (!error)
goto retry_deleg;
}
+ if (value != orig_value)
+ kfree(value);
+
return error;
}
EXPORT_SYMBOL_GPL(vfs_setxattr);
@@ -537,12 +548,6 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
(strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
posix_acl_fix_xattr_from_user(kvalue, size);
- else if (strcmp(kname, XATTR_NAME_CAPS) == 0) {
- error = cap_convert_nscap(d, &kvalue, size);
- if (error < 0)
- goto out;
- size = error;
- }
}
error = vfs_setxattr(d, kname, kvalue, size, flags);
diff --git a/include/linux/capability.h b/include/linux/capability.h
index 1e7fe311cabe..b2f698915c0f 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -270,6 +270,6 @@ static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
/* audit system wants to get cap info from files as well */
extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
-extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
+extern int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size);
#endif /* !_LINUX_CAPABILITY_H */
diff --git a/security/commoncap.c b/security/commoncap.c
index 59bf3c1674c8..bacc1111d871 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -473,7 +473,7 @@ static bool validheader(size_t size, const struct vfs_cap_data *cap)
*
* If all is ok, we return the new size, on error return < 0.
*/
-int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size)
+int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size)
{
struct vfs_ns_cap_data *nscap;
uid_t nsrootid;
@@ -516,7 +516,6 @@ int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size)
nscap->magic_etc = cpu_to_le32(nsmagic);
memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32);
- kvfree(*ivalue);
*ivalue = nscap;
return newsize;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-03 17:08:43 +0300