From 6a480a7842545ec520a91730209ec0bae41694c1 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 4 May 2016 14:04:13 -0400 Subject: ecryptfs: fix handling of directory opening First of all, trying to open them r/w is idiocy; it's guaranteed to fail. Moreover, assigning ->f_pos and assuming that everything will work is blatantly broken - try that with e.g. tmpfs as underlying layer and watch the fireworks. There may be a non-trivial amount of state associated with current IO position, well beyond the numeric offset. Using the single struct file associated with underlying inode is really not a good idea; we ought to open one for each ecryptfs directory struct file. Additionally, file_operations both for directories and non-directories are full of pointless methods; non-directories should *not* have ->iterate(), directories should not have ->flush(), ->fasync() and ->splice_read(). Signed-off-by: Al Viro --- fs/ecryptfs/file.c | 71 ++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 55 insertions(+), 16 deletions(-) (limited to 'fs/ecryptfs') diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index feef8a9c4de7..f02404052b7b 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -112,7 +112,6 @@ static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) .sb = inode->i_sb, }; lower_file = ecryptfs_file_to_lower(file); - lower_file->f_pos = ctx->pos; rc = iterate_dir(lower_file, &buf.ctx); ctx->pos = buf.ctx.pos; if (rc < 0) @@ -223,14 +222,6 @@ static int ecryptfs_open(struct inode *inode, struct file *file) } ecryptfs_set_file_lower( file, ecryptfs_inode_to_private(inode)->lower_file); - if (d_is_dir(ecryptfs_dentry)) { - ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); - mutex_lock(&crypt_stat->cs_mutex); - crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); - mutex_unlock(&crypt_stat->cs_mutex); - rc = 0; - goto out; - } rc = read_or_initialize_metadata(ecryptfs_dentry); if (rc) goto out_put; @@ -247,6 +238,45 @@ out: return rc; } +/** + * ecryptfs_dir_open + * @inode: inode speciying file to open + * @file: Structure to return filled in + * + * Opens the file specified by inode. + * + * Returns zero on success; non-zero otherwise + */ +static int ecryptfs_dir_open(struct inode *inode, struct file *file) +{ + struct dentry *ecryptfs_dentry = file->f_path.dentry; + /* Private value of ecryptfs_dentry allocated in + * ecryptfs_lookup() */ + struct ecryptfs_file_info *file_info; + struct file *lower_file; + + /* Released in ecryptfs_release or end of function if failure */ + file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); + ecryptfs_set_file_private(file, file_info); + if (unlikely(!file_info)) { + ecryptfs_printk(KERN_ERR, + "Error attempting to allocate memory\n"); + return -ENOMEM; + } + lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry), + file->f_flags, current_cred()); + if (IS_ERR(lower_file)) { + printk(KERN_ERR "%s: Error attempting to initialize " + "the lower file for the dentry with name " + "[%pd]; rc = [%ld]\n", __func__, + ecryptfs_dentry, PTR_ERR(lower_file)); + kmem_cache_free(ecryptfs_file_info_cache, file_info); + return PTR_ERR(lower_file); + } + ecryptfs_set_file_lower(file, lower_file); + return 0; +} + static int ecryptfs_flush(struct file *file, fl_owner_t td) { struct file *lower_file = ecryptfs_file_to_lower(file); @@ -267,6 +297,19 @@ static int ecryptfs_release(struct inode *inode, struct file *file) return 0; } +static int ecryptfs_dir_release(struct inode *inode, struct file *file) +{ + fput(ecryptfs_file_to_lower(file)); + kmem_cache_free(ecryptfs_file_info_cache, + ecryptfs_file_to_private(file)); + return 0; +} + +static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence) +{ + return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence); +} + static int ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) { @@ -346,20 +389,16 @@ const struct file_operations ecryptfs_dir_fops = { #ifdef CONFIG_COMPAT .compat_ioctl = ecryptfs_compat_ioctl, #endif - .open = ecryptfs_open, - .flush = ecryptfs_flush, - .release = ecryptfs_release, + .open = ecryptfs_dir_open, + .release = ecryptfs_dir_release, .fsync = ecryptfs_fsync, - .fasync = ecryptfs_fasync, - .splice_read = generic_file_splice_read, - .llseek = default_llseek, + .llseek = ecryptfs_dir_llseek, }; const struct file_operations ecryptfs_main_fops = { .llseek = generic_file_llseek, .read_iter = ecryptfs_read_update_atime, .write_iter = generic_file_write_iter, - .iterate = ecryptfs_readdir, .unlocked_ioctl = ecryptfs_unlocked_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = ecryptfs_compat_ioctl, -- cgit v1.2.3-59-g8ed1b