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Commit 80b742b8 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Greg Kroah-Hartman
Browse files

fuse: listxattr: verify xattr list 



commit cb3ae6d25a5471be62bfe6ac1fccc0e91edeaba0 upstream.

Make sure userspace filesystem is returning a well formed list of xattr
names (zero or more nonzero length, null terminated strings).

[Michael Theall: only verify in the nonzero size case]

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1ccdc775

fs/fuse/dir.c

+19 −0
Original line number Diff line number Diff line
@@ -1797,6 +1797,23 @@ static ssize_t fuse_getxattr(struct dentry *entry, const char *name, 
	return ret;

}



static int fuse_verify_xattr_list(char *list, size_t size)

{

	size_t origsize = size;



	while (size) {

		size_t thislen = strnlen(list, size);



		if (!thislen || thislen == size)

			return -EIO;



		size -= thislen + 1;

		list += thislen + 1;

	}



	return origsize;

}



static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)

{

	struct inode *inode = d_inode(entry);
@@ -1832,6 +1849,8 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size) 
	ret = fuse_simple_request(fc, &args);

	if (!ret && !size)

		ret = outarg.size;

	if (ret > 0 && size)

		ret = fuse_verify_xattr_list(list, ret);

	if (ret == -ENOSYS) {

		fc->no_listxattr = 1;

		ret = -EOPNOTSUPP;