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path: root/fs/overlayfs/namei.c
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Diffstat (limited to 'fs/overlayfs/namei.c')
-rw-r--r--fs/overlayfs/namei.c195
1 files changed, 123 insertions, 72 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index c993dd8db739..f28711846dd6 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -24,38 +24,20 @@ struct ovl_lookup_data {
bool stop;
bool last;
char *redirect;
+ bool metacopy;
};
static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
size_t prelen, const char *post)
{
int res;
- char *s, *next, *buf = NULL;
+ char *buf;
- res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
- if (res < 0) {
- if (res == -ENODATA || res == -EOPNOTSUPP)
- return 0;
- goto fail;
- }
- buf = kzalloc(prelen + res + strlen(post) + 1, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
+ buf = ovl_get_redirect_xattr(dentry, prelen + strlen(post));
+ if (IS_ERR_OR_NULL(buf))
+ return PTR_ERR(buf);
- if (res == 0)
- goto invalid;
-
- res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
- if (res < 0)
- goto fail;
- if (res == 0)
- goto invalid;
if (buf[0] == '/') {
- for (s = buf; *s++ == '/'; s = next) {
- next = strchrnul(s, '/');
- if (s == next)
- goto invalid;
- }
/*
* One of the ancestor path elements in an absolute path
* lookup in ovl_lookup_layer() could have been opaque and
@@ -66,9 +48,7 @@ static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
*/
d->stop = false;
} else {
- if (strchr(buf, '/') != NULL)
- goto invalid;
-
+ res = strlen(buf) + 1;
memmove(buf + prelen, buf, res);
memcpy(buf, d->name.name, prelen);
}
@@ -80,16 +60,6 @@ static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
d->name.len = strlen(d->redirect);
return 0;
-
-err_free:
- kfree(buf);
- return 0;
-fail:
- pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);
- goto err_free;
-invalid:
- pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
- goto err_free;
}
static int ovl_acceptable(void *ctx, struct dentry *dentry)
@@ -252,28 +222,39 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
d->stop = d->opaque = true;
goto put_and_out;
}
- if (!d_can_lookup(this)) {
+ /*
+ * This dentry should be a regular file if previous layer lookup
+ * found a metacopy dentry.
+ */
+ if (last_element && d->metacopy && !d_is_reg(this)) {
d->stop = true;
- if (d->is_dir)
- goto put_and_out;
-
- /*
- * NB: handle failure to lookup non-last element when non-dir
- * redirects become possible
- */
- WARN_ON(!last_element);
- goto out;
+ goto put_and_out;
}
- if (last_element)
- d->is_dir = true;
- if (d->last)
- goto out;
+ if (!d_can_lookup(this)) {
+ if (d->is_dir || !last_element) {
+ d->stop = true;
+ goto put_and_out;
+ }
+ err = ovl_check_metacopy_xattr(this);
+ if (err < 0)
+ goto out_err;
- if (ovl_is_opaquedir(this)) {
- d->stop = true;
+ d->metacopy = err;
+ d->stop = !d->metacopy;
+ if (!d->metacopy || d->last)
+ goto out;
+ } else {
if (last_element)
- d->opaque = true;
- goto out;
+ d->is_dir = true;
+ if (d->last)
+ goto out;
+
+ if (ovl_is_opaquedir(this)) {
+ d->stop = true;
+ if (last_element)
+ d->opaque = true;
+ goto out;
+ }
}
err = ovl_check_redirect(this, d, prelen, post);
if (err)
@@ -823,7 +804,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
struct ovl_entry *poe = dentry->d_parent->d_fsdata;
struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata;
- struct ovl_path *stack = NULL;
+ struct ovl_path *stack = NULL, *origin_path = NULL;
struct dentry *upperdir, *upperdentry = NULL;
struct dentry *origin = NULL;
struct dentry *index = NULL;
@@ -834,6 +815,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
struct dentry *this;
unsigned int i;
int err;
+ bool metacopy = false;
struct ovl_lookup_data d = {
.name = dentry->d_name,
.is_dir = false,
@@ -841,6 +823,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
.stop = false,
.last = ofs->config.redirect_follow ? false : !poe->numlower,
.redirect = NULL,
+ .metacopy = false,
};
if (dentry->d_name.len > ofs->namelen)
@@ -859,7 +842,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
goto out;
}
if (upperdentry && !d.is_dir) {
- BUG_ON(!d.stop || d.redirect);
+ unsigned int origin_ctr = 0;
+
/*
* Lookup copy up origin by decoding origin file handle.
* We may get a disconnected dentry, which is fine,
@@ -870,9 +854,13 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* number - it's the same as if we held a reference
* to a dentry in lower layer that was moved under us.
*/
- err = ovl_check_origin(ofs, upperdentry, &stack, &ctr);
+ err = ovl_check_origin(ofs, upperdentry, &origin_path,
+ &origin_ctr);
if (err)
goto out_put_upper;
+
+ if (d.metacopy)
+ metacopy = true;
}
if (d.redirect) {
@@ -913,7 +901,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* If no origin fh is stored in upper of a merge dir, store fh
* of lower dir and set upper parent "impure".
*/
- if (upperdentry && !ctr && !ofs->noxattr) {
+ if (upperdentry && !ctr && !ofs->noxattr && d.is_dir) {
err = ovl_fix_origin(dentry, this, upperdentry);
if (err) {
dput(this);
@@ -925,18 +913,35 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
* When "verify_lower" feature is enabled, do not merge with a
* lower dir that does not match a stored origin xattr. In any
* case, only verified origin is used for index lookup.
+ *
+ * For non-dir dentry, if index=on, then ensure origin
+ * matches the dentry found using path based lookup,
+ * otherwise error out.
*/
- if (upperdentry && !ctr && ovl_verify_lower(dentry->d_sb)) {
+ if (upperdentry && !ctr &&
+ ((d.is_dir && ovl_verify_lower(dentry->d_sb)) ||
+ (!d.is_dir && ofs->config.index && origin_path))) {
err = ovl_verify_origin(upperdentry, this, false);
if (err) {
dput(this);
- break;
+ if (d.is_dir)
+ break;
+ goto out_put;
}
-
- /* Bless lower dir as verified origin */
origin = this;
}
+ if (d.metacopy)
+ metacopy = true;
+ /*
+ * Do not store intermediate metacopy dentries in chain,
+ * except top most lower metacopy dentry
+ */
+ if (d.metacopy && ctr) {
+ dput(this);
+ continue;
+ }
+
stack[ctr].dentry = this;
stack[ctr].layer = lower.layer;
ctr++;
@@ -968,13 +973,48 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
}
}
+ if (metacopy) {
+ /*
+ * Found a metacopy dentry but did not find corresponding
+ * data dentry
+ */
+ if (d.metacopy) {
+ err = -EIO;
+ goto out_put;
+ }
+
+ err = -EPERM;
+ if (!ofs->config.metacopy) {
+ pr_warn_ratelimited("overlay: refusing to follow metacopy origin for (%pd2)\n",
+ dentry);
+ goto out_put;
+ }
+ } else if (!d.is_dir && upperdentry && !ctr && origin_path) {
+ if (WARN_ON(stack != NULL)) {
+ err = -EIO;
+ goto out_put;
+ }
+ stack = origin_path;
+ ctr = 1;
+ origin_path = NULL;
+ }
+
/*
* Lookup index by lower inode and verify it matches upper inode.
* We only trust dir index if we verified that lower dir matches
* origin, otherwise dir index entries may be inconsistent and we
- * ignore them. Always lookup index of non-dir and non-upper.
+ * ignore them.
+ *
+ * For non-dir upper metacopy dentry, we already set "origin" if we
+ * verified that lower matched upper origin. If upper origin was
+ * not present (because lower layer did not support fh encode/decode),
+ * or indexing is not enabled, do not set "origin" and skip looking up
+ * index. This case should be handled in same way as a non-dir upper
+ * without ORIGIN is handled.
+ *
+ * Always lookup index of non-dir non-metacopy and non-upper.
*/
- if (ctr && (!upperdentry || !d.is_dir))
+ if (ctr && (!upperdentry || (!d.is_dir && !metacopy)))
origin = stack[0].dentry;
if (origin && ovl_indexdir(dentry->d_sb) &&
@@ -1000,8 +1040,15 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (upperdentry)
ovl_dentry_set_upper_alias(dentry);
- else if (index)
+ else if (index) {
upperdentry = dget(index);
+ upperredirect = ovl_get_redirect_xattr(upperdentry, 0);
+ if (IS_ERR(upperredirect)) {
+ err = PTR_ERR(upperredirect);
+ upperredirect = NULL;
+ goto out_free_oe;
+ }
+ }
if (upperdentry || ctr) {
struct ovl_inode_params oip = {
@@ -1009,22 +1056,22 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
.lowerpath = stack,
.index = index,
.numlower = ctr,
+ .redirect = upperredirect,
+ .lowerdata = (ctr > 1 && !d.is_dir) ?
+ stack[ctr - 1].dentry : NULL,
};
inode = ovl_get_inode(dentry->d_sb, &oip);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_free_oe;
-
- /*
- * NB: handle redirected hard links when non-dir redirects
- * become possible
- */
- WARN_ON(OVL_I(inode)->redirect);
- OVL_I(inode)->redirect = upperredirect;
}
revert_creds(old_cred);
+ if (origin_path) {
+ dput(origin_path->dentry);
+ kfree(origin_path);
+ }
dput(index);
kfree(stack);
kfree(d.redirect);
@@ -1039,6 +1086,10 @@ out_put:
dput(stack[i].dentry);
kfree(stack);
out_put_upper:
+ if (origin_path) {
+ dput(origin_path->dentry);
+ kfree(origin_path);
+ }
dput(upperdentry);
kfree(upperredirect);
out:
generated by cgit (git 2.34.1) at 2024-06-09 17:46:27 +0000