int ovl_copy_xattr(struct dentry *old, struct dentry *new)
{
- ssize_t list_size, size;
- char *buf, *name, *value;
- int error;
+ ssize_t list_size, size, value_size = 0;
+ char *buf, *name, *value = NULL;
+ int uninitialized_var(error);
if (!old->d_inode->i_op->getxattr ||
!new->d_inode->i_op->getxattr)
if (!buf)
return -ENOMEM;
- error = -ENOMEM;
- value = kmalloc(XATTR_SIZE_MAX, GFP_KERNEL);
- if (!value)
- goto out;
-
list_size = vfs_listxattr(old, buf, list_size);
if (list_size <= 0) {
error = list_size;
- goto out_free_value;
+ goto out;
}
for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
- size = vfs_getxattr(old, name, value, XATTR_SIZE_MAX);
- if (size <= 0) {
+ retry:
+ size = vfs_getxattr(old, name, value, value_size);
+ if (size == -ERANGE)
+ size = vfs_getxattr(old, name, NULL, 0);
+
+ if (size < 0) {
error = size;
- goto out_free_value;
+ break;
}
+
+ if (size > value_size) {
+ void *new;
+
+ new = krealloc(value, size, GFP_KERNEL);
+ if (!new) {
+ error = -ENOMEM;
+ break;
+ }
+ value = new;
+ value_size = size;
+ goto retry;
+ }
+
error = vfs_setxattr(new, name, value, size, 0);
if (error)
- goto out_free_value;
+ break;
}
-
- out_free_value:
kfree(value);
out:
kfree(buf);
static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
struct dentry *dentry, struct path *lowerpath,
- struct kstat *stat, struct iattr *attr,
- const char *link)
+ struct kstat *stat, const char *link)
{
struct inode *wdir = workdir->d_inode;
struct inode *udir = upperdir->d_inode;
mutex_lock(&newdentry->d_inode->i_mutex);
err = ovl_set_attr(newdentry, stat);
- if (!err && attr)
- err = notify_change(newdentry, attr, NULL);
mutex_unlock(&newdentry->d_inode->i_mutex);
if (err)
goto out_cleanup;
* that point the file will have already been copied up anyway.
*/
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
- struct path *lowerpath, struct kstat *stat,
- struct iattr *attr)
+ struct path *lowerpath, struct kstat *stat)
{
struct dentry *workdir = ovl_workdir(dentry);
int err;
}
upperdentry = ovl_dentry_upper(dentry);
if (upperdentry) {
- unlock_rename(workdir, upperdir);
+ /* Raced with another copy-up? Nothing to do, then... */
err = 0;
- /* Raced with another copy-up? Do the setattr here */
- if (attr) {
- mutex_lock(&upperdentry->d_inode->i_mutex);
- err = notify_change(upperdentry, attr, NULL);
- mutex_unlock(&upperdentry->d_inode->i_mutex);
- }
- goto out_put_cred;
+ goto out_unlock;
}
err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
- stat, attr, link);
+ stat, link);
if (!err) {
/* Restore timestamps on parent (best effort) */
ovl_set_timestamps(upperdir, &pstat);
}
out_unlock:
unlock_rename(workdir, upperdir);
-out_put_cred:
revert_creds(old_cred);
put_cred(override_cred);
ovl_path_lower(next, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
if (!err)
- err = ovl_copy_up_one(parent, next, &lowerpath, &stat, NULL);
+ err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
dput(parent);
dput(next);
#include <linux/xattr.h>
#include "overlayfs.h"
-static int ovl_copy_up_last(struct dentry *dentry, struct iattr *attr,
- bool no_data)
+static int ovl_copy_up_truncate(struct dentry *dentry)
{
int err;
struct dentry *parent;
if (err)
goto out_dput_parent;
- if (no_data)
- stat.size = 0;
-
- err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat, attr);
+ stat.size = 0;
+ err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
out_dput_parent:
dput(parent);
int err;
struct dentry *upperdentry;
+ /*
+ * Check for permissions before trying to copy-up. This is redundant
+ * since it will be rechecked later by ->setattr() on upper dentry. But
+ * without this, copy-up can be triggered by just about anybody.
+ *
+ * We don't initialize inode->size, which just means that
+ * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
+ * check for a swapfile (which this won't be anyway).
+ */
+ err = inode_change_ok(dentry->d_inode, attr);
+ if (err)
+ return err;
+
err = ovl_want_write(dentry);
if (err)
goto out;
- upperdentry = ovl_dentry_upper(dentry);
- if (upperdentry) {
+ err = ovl_copy_up(dentry);
+ if (!err) {
+ upperdentry = ovl_dentry_upper(dentry);
+
mutex_lock(&upperdentry->d_inode->i_mutex);
err = notify_change(upperdentry, attr, NULL);
mutex_unlock(&upperdentry->d_inode->i_mutex);
- } else {
- err = ovl_copy_up_last(dentry, attr, false);
}
ovl_drop_write(dentry);
out:
realdentry = ovl_entry_real(oe, &is_upper);
+ if (ovl_is_default_permissions(inode)) {
+ struct kstat stat;
+ struct path realpath = { .dentry = realdentry };
+
+ if (mask & MAY_NOT_BLOCK)
+ return -ECHILD;
+
+ realpath.mnt = ovl_entry_mnt_real(oe, inode, is_upper);
+
+ err = vfs_getattr(&realpath, &stat);
+ if (err)
+ return err;
+
+ if ((stat.mode ^ inode->i_mode) & S_IFMT)
+ return -ESTALE;
+
+ inode->i_mode = stat.mode;
+ inode->i_uid = stat.uid;
+ inode->i_gid = stat.gid;
+
+ return generic_permission(inode, mask);
+ }
+
/* Careful in RCU walk mode */
realinode = ACCESS_ONCE(realdentry->d_inode);
if (!realinode) {
return err;
}
-
-struct ovl_link_data {
- struct dentry *realdentry;
- void *cookie;
-};
-
-static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
+static const char *ovl_get_link(struct dentry *dentry,
+ struct inode *inode,
+ struct delayed_call *done)
{
struct dentry *realdentry;
struct inode *realinode;
- struct ovl_link_data *data = NULL;
- const char *ret;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;
- if (WARN_ON(!realinode->i_op->follow_link))
+ if (WARN_ON(!realinode->i_op->get_link))
return ERR_PTR(-EPERM);
- if (realinode->i_op->put_link) {
- data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
- if (!data)
- return ERR_PTR(-ENOMEM);
- data->realdentry = realdentry;
- }
-
- ret = realinode->i_op->follow_link(realdentry, cookie);
- if (IS_ERR_OR_NULL(ret)) {
- kfree(data);
- return ret;
- }
-
- if (data)
- data->cookie = *cookie;
-
- *cookie = data;
-
- return ret;
-}
-
-static void ovl_put_link(struct inode *unused, void *c)
-{
- struct inode *realinode;
- struct ovl_link_data *data = c;
-
- if (!data)
- return;
-
- realinode = data->realdentry->d_inode;
- realinode->i_op->put_link(realinode, data->cookie);
- kfree(data);
+ return realinode->i_op->get_link(realdentry, realinode, done);
}
static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
return ERR_PTR(err);
if (file_flags & O_TRUNC)
- err = ovl_copy_up_last(dentry, NULL, true);
+ err = ovl_copy_up_truncate(dentry);
else
err = ovl_copy_up(dentry);
ovl_drop_write(dentry);
static const struct inode_operations ovl_symlink_inode_operations = {
.setattr = ovl_setattr,
- .follow_link = ovl_follow_link,
- .put_link = ovl_put_link,
+ .get_link = ovl_get_link,
.readlink = ovl_readlink,
.getattr = ovl_getattr,
.setxattr = ovl_setxattr,
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper);
+ struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
+ bool is_upper);
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
+ bool ovl_is_default_permissions(struct inode *inode);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
struct dentry *ovl_workdir(struct dentry *dentry);
int ovl_want_write(struct dentry *dentry);
/* copy_up.c */
int ovl_copy_up(struct dentry *dentry);
int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
- struct path *lowerpath, struct kstat *stat,
- struct iattr *attr);
+ struct path *lowerpath, struct kstat *stat);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
#include <linux/fs.h>
#include <linux/namei.h>
+ #include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/mount.h>
MODULE_DESCRIPTION("Overlay filesystem");
MODULE_LICENSE("GPL");
- #define OVERLAYFS_SUPER_MAGIC 0x794c7630
-
struct ovl_config {
char *lowerdir;
char *upperdir;
char *workdir;
+ bool default_permissions;
};
/* private information held for overlayfs's superblock */
return realdentry;
}
+ struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
+ bool is_upper)
+ {
+ if (is_upper) {
+ struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+
+ return ofs->upper_mnt;
+ } else {
+ return oe->numlower ? oe->lowerstack[0].mnt : NULL;
+ }
+ }
+
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
return oe->cache;
}
+ bool ovl_is_default_permissions(struct inode *inode)
+ {
+ struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+
+ return ofs->config.default_permissions;
+ }
+
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
{
struct ovl_entry *oe = dentry->d_fsdata;
struct super_block *sb = dentry->d_sb;
struct ovl_fs *ufs = sb->s_fs_info;
- seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);
+ seq_show_option(m, "lowerdir", ufs->config.lowerdir);
if (ufs->config.upperdir) {
- seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
- seq_printf(m, ",workdir=%s", ufs->config.workdir);
+ seq_show_option(m, "upperdir", ufs->config.upperdir);
+ seq_show_option(m, "workdir", ufs->config.workdir);
}
+ if (ufs->config.default_permissions)
+ seq_puts(m, ",default_permissions");
return 0;
}
OPT_LOWERDIR,
OPT_UPPERDIR,
OPT_WORKDIR,
+ OPT_DEFAULT_PERMISSIONS,
OPT_ERR,
};
{OPT_LOWERDIR, "lowerdir=%s"},
{OPT_UPPERDIR, "upperdir=%s"},
{OPT_WORKDIR, "workdir=%s"},
+ {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
{OPT_ERR, NULL}
};
return -ENOMEM;
break;
+ case OPT_DEFAULT_PERMISSIONS:
+ config->default_permissions = true;
+ break;
+
default:
pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
return -EINVAL;
}
sb->s_stack_depth = 0;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
if (ufs->config.upperdir) {
if (!ufs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
root_dentry->d_fsdata = oe;
+ ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode,
+ root_dentry->d_inode);
+
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
sb->s_op = &ovl_super_operations;
sb->s_root = root_dentry;
#define PSTOREFS_MAGIC 0x6165676C
#define EFIVARFS_MAGIC 0xde5e81e4
#define HOSTFS_SUPER_MAGIC 0x00c0ffee
+ #define OVERLAYFS_SUPER_MAGIC 0x794c7630
#define MINIX_SUPER_MAGIC 0x137F /* minix v1 fs, 14 char names */
#define MINIX_SUPER_MAGIC2 0x138F /* minix v1 fs, 30 char names */
#define SMB_SUPER_MAGIC 0x517B
#define CGROUP_SUPER_MAGIC 0x27e0eb
+#define CGROUP2_SUPER_MAGIC 0x63677270
#define STACK_END_MAGIC 0x57AC6E9D
#define ANON_INODE_FS_MAGIC 0x09041934
#define BTRFS_TEST_MAGIC 0x73727279
#define NSFS_MAGIC 0x6e736673
+#define BPF_FS_MAGIC 0xcafe4a11
#endif /* __LINUX_MAGIC_H__ */
projects / cascardo / linux.git / commitdiff