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Commit 6902d925 authored by Dave Hansen's avatar Dave Hansen Committed by Linus Torvalds
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[PATCH] r/o bind mounts: prepare for write access checks: collapse if() 



We're shortly going to be adding a bunch more permission checks in these
functions.  That requires adding either a bunch of new if() conditions, or
some gotos.  This patch collapses existing if()s and uses gotos instead to
prepare for the upcoming changes.

Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Acked-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent db5fed26

fs/namei.c

+50 −43
Original line number Diff line number Diff line
@@ -1934,30 +1934,32 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) 
{

	int error = 0;

	char * tmp;

	struct dentry *dentry;

	struct nameidata nd;



	tmp = getname(pathname);

	error = PTR_ERR(tmp);

	if (!IS_ERR(tmp)) {

		struct dentry *dentry;

		struct nameidata nd;

	if (IS_ERR(tmp))

		goto out_err;



	error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);

	if (error)

		goto out;

	dentry = lookup_create(&nd, 1);

	error = PTR_ERR(dentry);

		if (!IS_ERR(dentry)) {

	if (IS_ERR(dentry))

		goto out_unlock;



	if (!IS_POSIXACL(nd.dentry->d_inode))

		mode &= ~current->fs->umask;

	error = vfs_mkdir(nd.dentry->d_inode, dentry, mode);

	dput(dentry);

		}

out_unlock:

	mutex_unlock(&nd.dentry->d_inode->i_mutex);

	path_release(&nd);

out:

	putname(tmp);

	}



out_err:

	return error;

}
@@ -2056,10 +2058,11 @@ static long do_rmdir(int dfd, const char __user *pathname) 
	mutex_lock_nested(&nd.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = lookup_hash(&nd);

	error = PTR_ERR(dentry);

	if (!IS_ERR(dentry)) {

	if (IS_ERR(dentry))

		goto exit2;

	error = vfs_rmdir(nd.dentry->d_inode, dentry);

	dput(dentry);

	}

exit2:

	mutex_unlock(&nd.dentry->d_inode->i_mutex);

exit1:

	path_release(&nd);
@@ -2199,30 +2202,33 @@ asmlinkage long sys_symlinkat(const char __user *oldname, 
	int error = 0;

	char * from;

	char * to;

	struct dentry *dentry;

	struct nameidata nd;



	from = getname(oldname);

	if(IS_ERR(from))

		return PTR_ERR(from);

	to = getname(newname);

	error = PTR_ERR(to);

	if (!IS_ERR(to)) {

		struct dentry *dentry;

		struct nameidata nd;

	if (IS_ERR(to))

		goto out_putname;



	error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);

	if (error)

		goto out;

	dentry = lookup_create(&nd, 0);

	error = PTR_ERR(dentry);

		if (!IS_ERR(dentry)) {

	if (IS_ERR(dentry))

		goto out_unlock;



	error = vfs_symlink(nd.dentry->d_inode, dentry, from, S_IALLUGO);

	dput(dentry);

		}

out_unlock:

	mutex_unlock(&nd.dentry->d_inode->i_mutex);

	path_release(&nd);

out:

	putname(to);

	}

out_putname:

	putname(from);

	return error;

}
@@ -2308,10 +2314,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, 
		goto out_release;

	new_dentry = lookup_create(&nd, 0);

	error = PTR_ERR(new_dentry);

	if (!IS_ERR(new_dentry)) {

	if (IS_ERR(new_dentry))

		goto out_unlock;

	error = vfs_link(old_nd.dentry, nd.dentry->d_inode, new_dentry);

	dput(new_dentry);

	}

out_unlock:

	mutex_unlock(&nd.dentry->d_inode->i_mutex);

out_release:

	path_release(&nd);

fs/open.c

+37 −27
Original line number Diff line number Diff line
@@ -386,15 +386,21 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode) 
		current->cap_effective = current->cap_permitted;



	res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);

	if (!res) {

	if (res)

		goto out;



	res = vfs_permission(&nd, mode);

	/* SuS v2 requires we report a read only fs too */

		if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)

		   && !special_file(nd.dentry->d_inode->i_mode))

	if(res || !(mode & S_IWOTH) ||

	   special_file(nd.dentry->d_inode->i_mode))

		goto out_path_release;



	if(IS_RDONLY(nd.dentry->d_inode))

		res = -EROFS;

		path_release(&nd);

	}



out_path_release:

	path_release(&nd);

out:

	current->fsuid = old_fsuid;

	current->fsgid = old_fsgid;

	current->cap_effective = old_cap;
@@ -603,10 +609,11 @@ asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) 
	int error;



	error = user_path_walk(filename, &nd);

	if (!error) {

	if (error)

		goto out;

	error = chown_common(nd.dentry, user, group);

	path_release(&nd);

	}

out:

	return error;

}
@@ -622,10 +629,10 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user, 


	follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;

	error = __user_walk_fd(dfd, filename, follow, &nd);

	if (!error) {

	if (error)

		goto out;

	error = chown_common(nd.dentry, user, group);

	path_release(&nd);

	}

out:

	return error;

}
@@ -636,10 +643,11 @@ asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group 
	int error;



	error = user_path_walk_link(filename, &nd);

	if (!error) {

	if (error)

		goto out;

	error = chown_common(nd.dentry, user, group);

	path_release(&nd);

	}

out:

	return error;

}
@@ -648,15 +656,17 @@ asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) 
{

	struct file * file;

	int error = -EBADF;

	struct dentry * dentry;



	file = fget(fd);

	if (file) {

		struct dentry * dentry;

	if (!file)

		goto out;



	dentry = file->f_dentry;

	audit_inode(NULL, dentry->d_inode);

	error = chown_common(dentry, user, group);

	fput(file);

	}

out:

	return error;

}