diff options
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/copy_up.c | 35 | ||||
| -rw-r--r-- | fs/overlayfs/dir.c | 61 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 1 | ||||
| -rw-r--r-- | fs/overlayfs/readdir.c | 53 | ||||
| -rw-r--r-- | fs/overlayfs/super.c | 22 |
5 files changed, 137 insertions, 35 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index d894e7cd9..cc514da6f 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -7,6 +7,7 @@ * the Free Software Foundation. */ +#include <linux/module.h> #include <linux/fs.h> #include <linux/slab.h> #include <linux/file.h> @@ -16,10 +17,41 @@ #include <linux/uaccess.h> #include <linux/sched.h> #include <linux/namei.h> +#include <linux/fdtable.h> +#include <linux/ratelimit.h> #include "overlayfs.h" #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) +static bool __read_mostly ovl_check_copy_up; +module_param_named(check_copy_up, ovl_check_copy_up, bool, + S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(ovl_check_copy_up, + "Warn on copy-up when causing process also has a R/O fd open"); + +static int ovl_check_fd(const void *data, struct file *f, unsigned int fd) +{ + const struct dentry *dentry = data; + + if (f->f_inode == d_inode(dentry)) + pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n", + f, fd, current->pid, current->comm); + return 0; +} + +/* + * Check the fds open by this process and warn if something like the following + * scenario is about to occur: + * + * fd1 = open("foo", O_RDONLY); + * fd2 = open("foo", O_RDWR); + */ +static void ovl_do_check_copy_up(struct dentry *dentry) +{ + if (ovl_check_copy_up) + iterate_fd(current->files, 0, ovl_check_fd, dentry); +} + int ovl_copy_xattr(struct dentry *old, struct dentry *new) { ssize_t list_size, size, value_size = 0; @@ -235,6 +267,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, if (S_ISREG(stat->mode)) { struct path upperpath; + ovl_path_upper(dentry, &upperpath); BUG_ON(upperpath.dentry != NULL); upperpath.dentry = newdentry; @@ -309,6 +342,8 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, if (WARN_ON(!workdir)) return -EROFS; + ovl_do_check_copy_up(lowerpath->dentry); + ovl_path_upper(parent, &parentpath); upperdir = parentpath.dentry; diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 52f6de5d4..b3fc0a35b 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -596,21 +596,25 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) { struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); struct inode *dir = upperdir->d_inode; - struct dentry *upper = ovl_dentry_upper(dentry); + struct dentry *upper; int err; inode_lock_nested(dir, I_MUTEX_PARENT); + upper = lookup_one_len(dentry->d_name.name, upperdir, + dentry->d_name.len); + err = PTR_ERR(upper); + if (IS_ERR(upper)) + goto out_unlock; + err = -ESTALE; - if (upper->d_parent == upperdir) { - /* Don't let d_delete() think it can reset d_inode */ - dget(upper); + if (upper == ovl_dentry_upper(dentry)) { if (is_dir) err = vfs_rmdir(dir, upper); else err = vfs_unlink(dir, upper, NULL); - dput(upper); ovl_dentry_version_inc(dentry->d_parent); } + dput(upper); /* * Keeping this dentry hashed would mean having to release @@ -620,6 +624,7 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) */ if (!err) d_drop(dentry); +out_unlock: inode_unlock(dir); return err; @@ -714,7 +719,6 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, struct dentry *trap; bool old_opaque; bool new_opaque; - bool new_create = false; bool cleanup_whiteout = false; bool overwrite = !(flags & RENAME_EXCHANGE); bool is_dir = d_is_dir(old); @@ -840,29 +844,38 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, trap = lock_rename(new_upperdir, old_upperdir); - olddentry = ovl_dentry_upper(old); - newdentry = ovl_dentry_upper(new); - if (newdentry) { + + olddentry = lookup_one_len(old->d_name.name, old_upperdir, + old->d_name.len); + err = PTR_ERR(olddentry); + if (IS_ERR(olddentry)) + goto out_unlock; + + err = -ESTALE; + if (olddentry != ovl_dentry_upper(old)) + goto out_dput_old; + + newdentry = lookup_one_len(new->d_name.name, new_upperdir, + new->d_name.len); + err = PTR_ERR(newdentry); + if (IS_ERR(newdentry)) + goto out_dput_old; + + err = -ESTALE; + if (ovl_dentry_upper(new)) { if (opaquedir) { - newdentry = opaquedir; - opaquedir = NULL; + if (newdentry != opaquedir) + goto out_dput; } else { - dget(newdentry); + if (newdentry != ovl_dentry_upper(new)) + goto out_dput; } } else { - new_create = true; - newdentry = lookup_one_len(new->d_name.name, new_upperdir, - new->d_name.len); - err = PTR_ERR(newdentry); - if (IS_ERR(newdentry)) - goto out_unlock; + if (!d_is_negative(newdentry) && + (!new_opaque || !ovl_is_whiteout(newdentry))) + goto out_dput; } - err = -ESTALE; - if (olddentry->d_parent != old_upperdir) - goto out_dput; - if (newdentry->d_parent != new_upperdir) - goto out_dput; if (olddentry == trap) goto out_dput; if (newdentry == trap) @@ -925,6 +938,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old, out_dput: dput(newdentry); +out_dput_old: + dput(olddentry); out_unlock: unlock_rename(new_upperdir, old_upperdir); out_revert_creds: diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 99b4168c3..6a7090f4a 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -166,6 +166,7 @@ extern const struct file_operations ovl_dir_operations; int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); void ovl_cache_free(struct list_head *list); +int ovl_check_d_type_supported(struct path *realpath); /* inode.c */ int ovl_setattr(struct dentry *dentry, struct iattr *attr); diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index fdaf28f75..6ec1e43a9 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -36,13 +36,14 @@ struct ovl_dir_cache { struct ovl_readdir_data { struct dir_context ctx; - bool is_merge; + bool is_lowest; struct rb_root root; struct list_head *list; struct list_head middle; struct ovl_cache_entry *first_maybe_whiteout; int count; int err; + bool d_type_supported; }; struct ovl_dir_file { @@ -139,9 +140,9 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd, return 0; } -static int ovl_fill_lower(struct ovl_readdir_data *rdd, - const char *name, int namelen, - loff_t offset, u64 ino, unsigned int d_type) +static int ovl_fill_lowest(struct ovl_readdir_data *rdd, + const char *name, int namelen, + loff_t offset, u64 ino, unsigned int d_type) { struct ovl_cache_entry *p; @@ -193,10 +194,10 @@ static int ovl_fill_merge(struct dir_context *ctx, const char *name, container_of(ctx, struct ovl_readdir_data, ctx); rdd->count++; - if (!rdd->is_merge) + if (!rdd->is_lowest) return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type); else - return ovl_fill_lower(rdd, name, namelen, offset, ino, d_type); + return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type); } static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) @@ -289,7 +290,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) .ctx.actor = ovl_fill_merge, .list = list, .root = RB_ROOT, - .is_merge = false, + .is_lowest = false, }; int idx, next; @@ -306,7 +307,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) * allows offsets to be reasonably constant */ list_add(&rdd.middle, rdd.list); - rdd.is_merge = true; + rdd.is_lowest = true; err = ovl_dir_read(&realpath, &rdd); list_del(&rdd.middle); } @@ -577,3 +578,39 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list) } inode_unlock(upper->d_inode); } + +static int ovl_check_d_type(struct dir_context *ctx, const char *name, + int namelen, loff_t offset, u64 ino, + unsigned int d_type) +{ + struct ovl_readdir_data *rdd = + container_of(ctx, struct ovl_readdir_data, ctx); + + /* Even if d_type is not supported, DT_DIR is returned for . and .. */ + if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen)) + return 0; + + if (d_type != DT_UNKNOWN) + rdd->d_type_supported = true; + + return 0; +} + +/* + * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values + * if error is encountered. + */ +int ovl_check_d_type_supported(struct path *realpath) +{ + int err; + struct ovl_readdir_data rdd = { + .ctx.actor = ovl_check_d_type, + .d_type_supported = false, + }; + + err = ovl_dir_read(realpath, &rdd); + if (err) + return err; + + return rdd.d_type_supported; +} diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 4399ea804..791235e03 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -411,9 +411,7 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir, { struct dentry *dentry; - inode_lock(dir->d_inode); - dentry = lookup_one_len(name->name, dir, name->len); - inode_unlock(dir->d_inode); + dentry = lookup_hash(name, dir); if (IS_ERR(dentry)) { if (PTR_ERR(dentry) == -ENOENT) @@ -969,7 +967,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) err = -EINVAL; if (!ufs->config.lowerdir) { - pr_err("overlayfs: missing 'lowerdir'\n"); + if (!silent) + pr_err("overlayfs: missing 'lowerdir'\n"); goto out_free_config; } @@ -1061,6 +1060,21 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_flags |= MS_RDONLY; ufs->workdir = NULL; } + + /* + * Upper should support d_type, else whiteouts are visible. + * Given workdir and upper are on same fs, we can do + * iterate_dir() on workdir. + */ + err = ovl_check_d_type_supported(&workpath); + if (err < 0) + goto out_put_workdir; + + if (!err) { + pr_err("overlayfs: upper fs needs to support d_type.\n"); + err = -EINVAL; + goto out_put_workdir; + } } err = -ENOMEM; |