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Commit 66cb7666 authored by Al Viro's avatar Al Viro
Browse files

sanitize ecryptfs ->mount() 



kill ecryptfs_read_super(), reorder code allowing to use
normal d_alloc_root() instead of opencoding it.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d61dcce2

fs/ecryptfs/inode.c

+0 −1
Original line number Diff line number Diff line
@@ -441,7 +441,6 @@ static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 
	struct qstr lower_name;

	int rc = 0;



	d_set_d_op(ecryptfs_dentry, &ecryptfs_dops);

	if ((ecryptfs_dentry->d_name.len == 1

	     && !strcmp(ecryptfs_dentry->d_name.name, "."))

	    || (ecryptfs_dentry->d_name.len == 2

fs/ecryptfs/main.c

+68 −87
Original line number Diff line number Diff line
@@ -141,21 +141,9 @@ int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) 
	return rc;

}



/**

 * ecryptfs_interpose

 * @lower_dentry: Existing dentry in the lower filesystem

 * @dentry: ecryptfs' dentry

 * @sb: ecryptfs's super_block

 * @flags: flags to govern behavior of interpose procedure

 *

 * Interposes upper and lower dentries.

 *

 * Returns zero on success; non-zero otherwise

 */

int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,

		       struct super_block *sb, u32 flags)

static inode *ecryptfs_get_inode(struct inode *lower_inode,

		       struct super_block *sb)

{

	struct inode *lower_inode;

	struct inode *inode;

	int rc = 0;
@@ -189,17 +177,38 @@ int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, 
	if (special_file(lower_inode->i_mode))

		init_special_inode(inode, lower_inode->i_mode,

				   lower_inode->i_rdev);

	d_set_d_op(dentry, &ecryptfs_dops);

	fsstack_copy_attr_all(inode, lower_inode);

	/* This size will be overwritten for real files w/ headers and

	 * other metadata */

	fsstack_copy_inode_size(inode, lower_inode);

	return inode;

out:

	return ERR_PTR(rc);

}



/**

 * ecryptfs_interpose

 * @lower_dentry: Existing dentry in the lower filesystem

 * @dentry: ecryptfs' dentry

 * @sb: ecryptfs's super_block

 * @flags: flags to govern behavior of interpose procedure

 *

 * Interposes upper and lower dentries.

 *

 * Returns zero on success; non-zero otherwise

 */

int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,

		       struct super_block *sb, u32 flags)

{

	struct inode *lower_inode = lower_dentry->d_inode;

	struct inode *inode = ecryptfs_get_inode(lower_inode, sb);

	if (IS_ERR(inode)

		return PTR_ERR(inode);

	if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)

		d_add(dentry, inode);

	else

		d_instantiate(dentry, inode);

out:

	return rc;

	return 0;

}



enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
@@ -491,60 +500,12 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options) 
struct kmem_cache *ecryptfs_sb_info_cache;

static struct file_system_type ecryptfs_fs_type;



/**

 * ecryptfs_read_super

 * @sb: The ecryptfs super block

 * @dev_name: The path to mount over

 *

 * Read the super block of the lower filesystem, and use

 * ecryptfs_interpose to create our initial inode and super block

 * struct.

 */

static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)

{

	struct path path;

	int rc;



	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);

	if (rc) {

		ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");

		goto out;

	}

	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {

		rc = -EINVAL;

		printk(KERN_ERR "Mount on filesystem of type "

			"eCryptfs explicitly disallowed due to "

			"known incompatibilities\n");

		goto out_free;

	}

	ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);

	sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;

	sb->s_blocksize = path.dentry->d_sb->s_blocksize;

	ecryptfs_set_dentry_lower(sb->s_root, path.dentry);

	ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);

	rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);

	if (rc)

		goto out_free;

	rc = 0;

	goto out;

out_free:

	path_put(&path);

out:

	return rc;

}



/**

 * ecryptfs_get_sb

 * @fs_type

 * @flags

 * @dev_name: The path to mount over

 * @raw_data: The options passed into the kernel

 *

 * The whole ecryptfs_get_sb process is broken into 3 functions:

 * ecryptfs_parse_options(): handle options passed to ecryptfs, if any

 * ecryptfs_read_super(): this accesses the lower filesystem and uses

 *                        ecryptfs_interpose to perform most of the linking

 * ecryptfs_interpose(): links the lower filesystem into ecryptfs (inode.c)

 */

static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,

			const char *dev_name, void *raw_data)
@@ -553,6 +514,8 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags 
	struct ecryptfs_sb_info *sbi;

	struct ecryptfs_dentry_info *root_info;

	const char *err = "Getting sb failed";

	struct inode *inode;

	struct path path;

	int rc;



	sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
@@ -575,10 +538,8 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags 


	s->s_flags = flags;

	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);

	if (rc) {

		deactivate_locked_super(s);

		goto out;

	}

	if (rc)

		goto out1;



	ecryptfs_set_superblock_private(s, sbi);

	s->s_bdi = &sbi->bdi;
@@ -586,34 +547,54 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags 
	/* ->kill_sb() will take care of sbi after that point */

	sbi = NULL;

	s->s_op = &ecryptfs_sops;

	s->s_d_op = &ecryptfs_dops;



	rc = -ENOMEM;

	s->s_root = d_alloc(NULL, &(const struct qstr) {

			     .hash = 0,.name = "/",.len = 1});

	err = "Reading sb failed";

	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);

	if (rc) {

		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");

		goto out1;

	}

	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {

		rc = -EINVAL;

		printk(KERN_ERR "Mount on filesystem of type "

			"eCryptfs explicitly disallowed due to "

			"known incompatibilities\n");

		goto out_free;

	}

	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);

	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;

	s->s_blocksize = path.dentry->d_sb->s_blocksize;



	inode = ecryptfs_get_inode(path.dentry->d_inode, s);

	rc = PTR_ERR(inode);

	if (IS_ERR(inode))

		goto out_free;



	s->s_root = d_alloc_root(inode);

	if (!s->s_root) {

		deactivate_locked_super(s);

		goto out;

		iput(inode);

		rc = -ENOMEM;

		goto out_free;

	}

	d_set_d_op(s->s_root, &ecryptfs_dops);

	s->s_root->d_sb = s;

	s->s_root->d_parent = s->s_root;



	rc = -ENOMEM;

	root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);

	if (!root_info) {

		deactivate_locked_super(s);

		goto out;

	}

	if (!root_info)

		goto out_free;



	/* ->kill_sb() will take care of root_info */

	ecryptfs_set_dentry_private(s->s_root, root_info);

	ecryptfs_set_dentry_lower(s->s_root, path.dentry);

	ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);



	s->s_flags |= MS_ACTIVE;

	rc = ecryptfs_read_super(s, dev_name);

	if (rc) {

		deactivate_locked_super(s);

		err = "Reading sb failed";

		goto out;

	}

	return dget(s->s_root);



out_free:

	path_put(&path);

out1:

	deactivate_locked_super(s);

out:

	if (sbi) {

		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);