diff options
Diffstat (limited to 'kernel/fs/overlayfs')
| -rw-r--r-- | kernel/fs/overlayfs/copy_up.c | 70 | ||||
| -rw-r--r-- | kernel/fs/overlayfs/dir.c | 10 | ||||
| -rw-r--r-- | kernel/fs/overlayfs/inode.c | 97 | ||||
| -rw-r--r-- | kernel/fs/overlayfs/overlayfs.h | 4 | ||||
| -rw-r--r-- | kernel/fs/overlayfs/readdir.c | 3 | ||||
| -rw-r--r-- | kernel/fs/overlayfs/super.c | 134 |
6 files changed, 208 insertions, 110 deletions
diff --git a/kernel/fs/overlayfs/copy_up.c b/kernel/fs/overlayfs/copy_up.c index 84d693d37..eff6319d5 100644 --- a/kernel/fs/overlayfs/copy_up.c +++ b/kernel/fs/overlayfs/copy_up.c @@ -22,9 +22,9 @@ 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) @@ -41,29 +41,40 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) 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); @@ -81,11 +92,11 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) if (len == 0) return 0; - old_file = ovl_path_open(old, O_RDONLY); + old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); if (IS_ERR(old_file)) return PTR_ERR(old_file); - new_file = ovl_path_open(new, O_WRONLY); + new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); if (IS_ERR(new_file)) { error = PTR_ERR(new_file); goto out_fput; @@ -195,8 +206,7 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) 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; @@ -240,8 +250,6 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, 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; @@ -267,7 +275,7 @@ out: out_cleanup: ovl_cleanup(wdir, newdentry); - goto out; + goto out2; } /* @@ -286,8 +294,7 @@ 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; @@ -345,26 +352,19 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, } 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); @@ -406,7 +406,7 @@ int ovl_copy_up(struct dentry *dentry) 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); diff --git a/kernel/fs/overlayfs/dir.c b/kernel/fs/overlayfs/dir.c index 692ceda3b..a2b1d7ce3 100644 --- a/kernel/fs/overlayfs/dir.c +++ b/kernel/fs/overlayfs/dir.c @@ -618,7 +618,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) * sole user of this dentry. Too tricky... Just unhash for * now. */ - d_drop(dentry); + if (!err) + d_drop(dentry); mutex_unlock(&dir->i_mutex); return err; @@ -903,6 +904,13 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, if (!overwrite && new_is_dir && !old_opaque && new_opaque) ovl_remove_opaque(newdentry); + /* + * Old dentry now lives in different location. Dentries in + * lowerstack are stale. We cannot drop them here because + * access to them is lockless. This could be only pure upper + * or opaque directory - numlower is zero. Or upper non-dir + * entry - its pureness is tracked by flag opaque. + */ if (old_opaque != new_opaque) { ovl_dentry_set_opaque(old, new_opaque); if (!overwrite) diff --git a/kernel/fs/overlayfs/inode.c b/kernel/fs/overlayfs/inode.c index 04f124884..05ac9a95e 100644 --- a/kernel/fs/overlayfs/inode.c +++ b/kernel/fs/overlayfs/inode.c @@ -12,8 +12,7 @@ #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; @@ -30,10 +29,8 @@ static int ovl_copy_up_last(struct dentry *dentry, struct iattr *attr, 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); @@ -45,17 +42,32 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr) 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); + if (!err) + ovl_copyattr(upperdentry->d_inode, dentry->d_inode); mutex_unlock(&upperdentry->d_inode->i_mutex); - } else { - err = ovl_copy_up_last(dentry, attr, false); } ovl_drop_write(dentry); out: @@ -140,11 +152,12 @@ struct ovl_link_data { void *cookie; }; -static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) +static const char *ovl_follow_link(struct dentry *dentry, void **cookie) { - void *ret; struct dentry *realdentry; struct inode *realinode; + struct ovl_link_data *data = NULL; + const char *ret; realdentry = ovl_dentry_real(dentry); realinode = realdentry->d_inode; @@ -152,28 +165,28 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) if (WARN_ON(!realinode->i_op->follow_link)) return ERR_PTR(-EPERM); - ret = realinode->i_op->follow_link(realdentry, nd); - if (IS_ERR(ret)) - return ret; - if (realinode->i_op->put_link) { - struct ovl_link_data *data; - data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL); - if (!data) { - realinode->i_op->put_link(realdentry, nd, ret); + if (!data) return ERR_PTR(-ENOMEM); - } data->realdentry = realdentry; - data->cookie = ret; + } - return data; - } else { - return NULL; + 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 dentry *dentry, struct nameidata *nd, void *c) +static void ovl_put_link(struct inode *unused, void *c) { struct inode *realinode; struct ovl_link_data *data = c; @@ -182,7 +195,7 @@ static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c) return; realinode = data->realdentry->d_inode; - realinode->i_op->put_link(data->realdentry, nd, data->cookie); + realinode->i_op->put_link(realinode, data->cookie); kfree(data); } @@ -336,37 +349,36 @@ static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type, return true; } -static int ovl_dentry_open(struct dentry *dentry, struct file *file, - const struct cred *cred) +struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags) { int err; struct path realpath; enum ovl_path_type type; - bool want_write = false; + + if (d_is_dir(dentry)) + return d_backing_inode(dentry); type = ovl_path_real(dentry, &realpath); - if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) { - want_write = true; + if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) { err = ovl_want_write(dentry); if (err) - goto out; + return ERR_PTR(err); - if (file->f_flags & O_TRUNC) - err = ovl_copy_up_last(dentry, NULL, true); + if (file_flags & O_TRUNC) + err = ovl_copy_up_truncate(dentry); else err = ovl_copy_up(dentry); + ovl_drop_write(dentry); if (err) - goto out_drop_write; + return ERR_PTR(err); ovl_path_upper(dentry, &realpath); } - err = vfs_open(&realpath, file, cred); -out_drop_write: - if (want_write) - ovl_drop_write(dentry); -out: - return err; + if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE) + return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags); + + return d_backing_inode(realpath.dentry); } static const struct inode_operations ovl_file_inode_operations = { @@ -377,7 +389,6 @@ static const struct inode_operations ovl_file_inode_operations = { .getxattr = ovl_getxattr, .listxattr = ovl_listxattr, .removexattr = ovl_removexattr, - .dentry_open = ovl_dentry_open, }; static const struct inode_operations ovl_symlink_inode_operations = { diff --git a/kernel/fs/overlayfs/overlayfs.h b/kernel/fs/overlayfs/overlayfs.h index 17ac5afc9..e17154aea 100644 --- a/kernel/fs/overlayfs/overlayfs.h +++ b/kernel/fs/overlayfs/overlayfs.h @@ -173,6 +173,7 @@ ssize_t ovl_getxattr(struct dentry *dentry, const char *name, void *value, size_t size); ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); int ovl_removexattr(struct dentry *dentry, const char *name); +struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags); struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, struct ovl_entry *oe); @@ -193,7 +194,6 @@ void ovl_cleanup(struct inode *dir, 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); diff --git a/kernel/fs/overlayfs/readdir.c b/kernel/fs/overlayfs/readdir.c index 70e9af551..adcb1398c 100644 --- a/kernel/fs/overlayfs/readdir.c +++ b/kernel/fs/overlayfs/readdir.c @@ -571,7 +571,8 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list) (int) PTR_ERR(dentry)); continue; } - ovl_cleanup(upper->d_inode, dentry); + if (dentry->d_inode) + ovl_cleanup(upper->d_inode, dentry); dput(dentry); } mutex_unlock(&upper->d_inode->i_mutex); diff --git a/kernel/fs/overlayfs/super.c b/kernel/fs/overlayfs/super.c index 155989455..000b2ed05 100644 --- a/kernel/fs/overlayfs/super.c +++ b/kernel/fs/overlayfs/super.c @@ -9,6 +9,7 @@ #include <linux/fs.h> #include <linux/namei.h> +#include <linux/pagemap.h> #include <linux/xattr.h> #include <linux/security.h> #include <linux/mount.h> @@ -75,12 +76,14 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry) if (oe->__upperdentry) { type = __OVL_PATH_UPPER; - if (oe->numlower) { - if (S_ISDIR(dentry->d_inode->i_mode)) - type |= __OVL_PATH_MERGE; - } else if (!oe->opaque) { + /* + * Non-dir dentry can hold lower dentry from previous + * location. Its purity depends only on opaque flag. + */ + if (oe->numlower && S_ISDIR(dentry->d_inode->i_mode)) + type |= __OVL_PATH_MERGE; + else if (!oe->opaque) type |= __OVL_PATH_PURE; - } } else { if (oe->numlower > 1) type |= __OVL_PATH_MERGE; @@ -273,8 +276,57 @@ static void ovl_dentry_release(struct dentry *dentry) } } +static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct ovl_entry *oe = dentry->d_fsdata; + unsigned int i; + int ret = 1; + + for (i = 0; i < oe->numlower; i++) { + struct dentry *d = oe->lowerstack[i].dentry; + + if (d->d_flags & DCACHE_OP_REVALIDATE) { + ret = d->d_op->d_revalidate(d, flags); + if (ret < 0) + return ret; + if (!ret) { + if (!(flags & LOOKUP_RCU)) + d_invalidate(d); + return -ESTALE; + } + } + } + return 1; +} + +static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct ovl_entry *oe = dentry->d_fsdata; + unsigned int i; + int ret = 1; + + for (i = 0; i < oe->numlower; i++) { + struct dentry *d = oe->lowerstack[i].dentry; + + if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { + ret = d->d_op->d_weak_revalidate(d, flags); + if (ret <= 0) + break; + } + } + return ret; +} + static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, + .d_select_inode = ovl_d_select_inode, +}; + +static const struct dentry_operations ovl_reval_dentry_operations = { + .d_release = ovl_dentry_release, + .d_select_inode = ovl_d_select_inode, + .d_revalidate = ovl_dentry_revalidate, + .d_weak_revalidate = ovl_dentry_weak_revalidate, }; static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) @@ -288,6 +340,20 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) return oe; } +static bool ovl_dentry_remote(struct dentry *dentry) +{ + return dentry->d_flags & + (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); +} + +static bool ovl_dentry_weird(struct dentry *dentry) +{ + return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | + DCACHE_MANAGE_TRANSIT | + DCACHE_OP_HASH | + DCACHE_OP_COMPARE); +} + static inline struct dentry *ovl_lookup_real(struct dentry *dir, struct qstr *name) { @@ -303,6 +369,10 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir, } else if (!dentry->d_inode) { dput(dentry); dentry = NULL; + } else if (ovl_dentry_weird(dentry)) { + dput(dentry); + /* Don't support traversing automounts and other weirdness */ + dentry = ERR_PTR(-EREMOTE); } return dentry; } @@ -350,6 +420,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, goto out; if (this) { + if (unlikely(ovl_dentry_remote(this))) { + dput(this); + err = -EREMOTE; + goto out; + } if (ovl_is_whiteout(this)) { dput(this); this = NULL; @@ -473,6 +548,7 @@ static void ovl_put_super(struct super_block *sb) mntput(ufs->upper_mnt); for (i = 0; i < ufs->numlower; i++) mntput(ufs->lower_mnt[i]); + kfree(ufs->lower_mnt); kfree(ufs->config.lowerdir); kfree(ufs->config.upperdir); @@ -694,25 +770,6 @@ static void ovl_unescape(char *s) } } -static bool ovl_is_allowed_fs_type(struct dentry *root) -{ - const struct dentry_operations *dop = root->d_op; - - /* - * We don't support: - * - automount filesystems - * - filesystems with revalidate (FIXME for lower layer) - * - filesystems with case insensitive names - */ - if (dop && - (dop->d_manage || dop->d_automount || - dop->d_revalidate || dop->d_weak_revalidate || - dop->d_compare || dop->d_hash)) { - return false; - } - return true; -} - static int ovl_mount_dir_noesc(const char *name, struct path *path) { int err = -EINVAL; @@ -727,7 +784,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) goto out; } err = -EINVAL; - if (!ovl_is_allowed_fs_type(path->dentry)) { + if (ovl_dentry_weird(path->dentry)) { pr_err("overlayfs: filesystem on '%s' not supported\n", name); goto out_put; } @@ -751,13 +808,21 @@ static int ovl_mount_dir(const char *name, struct path *path) if (tmp) { ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); + + if (!err) + if (ovl_dentry_remote(path->dentry)) { + pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", + tmp); + path_put(path); + err = -EINVAL; + } kfree(tmp); } return err; } static int ovl_lower_dir(const char *name, struct path *path, long *namelen, - int *stack_depth) + int *stack_depth, bool *remote) { int err; struct kstatfs statfs; @@ -774,6 +839,9 @@ static int ovl_lower_dir(const char *name, struct path *path, long *namelen, *namelen = max(*namelen, statfs.f_namelen); *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); + if (ovl_dentry_remote(path->dentry)) + *remote = true; + return 0; out_put: @@ -827,6 +895,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) unsigned int numlower; unsigned int stacklen = 0; unsigned int i; + bool remote = false; int err; err = -ENOMEM; @@ -845,6 +914,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) } 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"); @@ -900,7 +970,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) lower = lowertmp; for (numlower = 0; numlower < stacklen; numlower++) { err = ovl_lower_dir(lower, &stack[numlower], - &ufs->lower_namelen, &sb->s_stack_depth); + &ufs->lower_namelen, &sb->s_stack_depth, + &remote); if (err) goto out_put_lowerpath; @@ -958,7 +1029,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (!ufs->upper_mnt) sb->s_flags |= MS_RDONLY; - sb->s_d_op = &ovl_dentry_operations; + if (remote) + sb->s_d_op = &ovl_reval_dentry_operations; + else + sb->s_d_op = &ovl_dentry_operations; err = -ENOMEM; oe = ovl_alloc_entry(numlower); @@ -980,9 +1054,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) oe->lowerstack[i].dentry = stack[i].dentry; oe->lowerstack[i].mnt = ufs->lower_mnt[i]; } + kfree(stack); 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; |