Commit 8b399a02 authored by Ramon Nou's avatar Ramon Nou
Browse files

bound internal symlink traversal

parent 6796d246

src/client/gkfs_metadata.cpp

+21 −2
Original line number Diff line number Diff line
@@ -202,8 +202,13 @@ test_lock_file(const std::string& path) { 
 * @param flags

 * @return 0 on success, -1 on failure

 */

namespace {



constexpr unsigned int max_symlink_depth = 40;



int

gkfs_open(const std::string& path, mode_t mode, int flags) {

gkfs_open_impl(const std::string& path, mode_t mode, int flags,

               unsigned int symlink_depth) {



    LOG(DEBUG, "{}() called with path: \"{}\", mode: {}, flags: {}", __func__,

        path, mode, flags);
@@ -292,7 +297,14 @@ gkfs_open(const std::string& path, mode_t mode, int flags) { 
            errno = ELOOP;

            return -1;

        }

        return gkfs_open(md.target_path(), mode, flags);

        if(symlink_depth >= max_symlink_depth) {

            LOG(WARNING,

                "{}() symbolic link traversal exceeded {} links for '{}'",

                __func__, max_symlink_depth, path);

            errno = ELOOP;

            return -1;

        }

        return gkfs_open_impl(md.target_path(), mode, flags, symlink_depth + 1);

    }

    if(gkfs::config::metadata::rename_support) {

        if(md.blocks() == -1) {
@@ -376,6 +388,13 @@ gkfs_open(const std::string& path, mode_t mode, int flags) { 
    return fd;

}



} // namespace



int

gkfs_open(const std::string& path, mode_t mode, int flags) {

    return gkfs_open_impl(path, mode, flags, 0);

}



/**

 * Wrapper function for file/directory creation

 * errno may be set

tests/integration/directories/test_symlinks.py

+17 −0
Original line number Diff line number Diff line 
import stat

import os

import errno



import pytest
@@ -44,3 +45,19 @@ def test_symlink_type(client_fixture, request, gkfs_daemon): 


    assert found_link, "Symlink entry not found in readdir"

    assert found_target, "Target entry not found in readdir"





@pytest.mark.parametrize("client_fixture", ["gkfs_client", "gkfs_clientLibc"])

def test_symlink_cycle_returns_eloop(client_fixture, request, gkfs_daemon):

    """Opening a cyclic symlink must fail with ELOOP, not recurse indefinitely."""

    gkfs_client = request.getfixturevalue(client_fixture)

    mountdir = gkfs_daemon.mountdir

    link_a = mountdir / "cycle_a"

    link_b = mountdir / "cycle_b"



    assert gkfs_client.symlink(str(link_b), str(link_a)).retval == 0

    assert gkfs_client.symlink(str(link_a), str(link_b)).retval == 0



    ret = gkfs_client.open(link_a, os.O_RDONLY)

    assert ret.retval == -1

    assert ret.errno == errno.ELOOP