From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Maennich Date: Mon, 4 Mar 2019 12:26:39 +0000 Subject: [LTP] [PATCH v2] Add ltp pivot_root test In-Reply-To: <20190301185534.37513-1-paullawrence@google.com> References: <20190301185534.37513-1-paullawrence@google.com> Message-ID: <20190304122639.GA90147@google.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hi Paul! On Fri, Mar 01, 2019 at 10:55:34AM -0800, Paul Lawrence wrote: > Replaced license > Merged all files into one parameterized file > Modified touse test_brk where appropriate > > For the actual test results, using tst_brk from the child process > meant failures were not counted correctly, so I still use tst_res > and exit. Please let me know if there is a correct way of doing this. > > Signed-off-by: Paul Lawrence > --- > testcases/kernel/syscalls/pivot_root/Makefile | 11 ++ > .../kernel/syscalls/pivot_root/pivot_root01.c | 168 ++++++++++++++++++ > 2 files changed, 179 insertions(+) > create mode 100644 testcases/kernel/syscalls/pivot_root/Makefile > create mode 100644 testcases/kernel/syscalls/pivot_root/pivot_root01.c > > diff --git a/testcases/kernel/syscalls/pivot_root/Makefile b/testcases/kernel/syscalls/pivot_root/Makefile > new file mode 100644 > index 000000000..ce8f8cb68 > --- /dev/null > +++ b/testcases/kernel/syscalls/pivot_root/Makefile > @@ -0,0 +1,11 @@ > +# SPDX-License-Identifier: GPL-2.0-or-later > +# > +# Copyright (c) 2019 Google, Inc. > + > +top_srcdir ?= ../../../.. > + > +include $(top_srcdir)/include/mk/testcases.mk > + > +CFLAGS += -lcap > + > +include $(top_srcdir)/include/mk/generic_leaf_target.mk > diff --git a/testcases/kernel/syscalls/pivot_root/pivot_root01.c b/testcases/kernel/syscalls/pivot_root/pivot_root01.c > new file mode 100644 > index 000000000..3aa939ac9 > --- /dev/null > +++ b/testcases/kernel/syscalls/pivot_root/pivot_root01.c > @@ -0,0 +1,168 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +// > +// Copyright (c) 2019 Google, Inc. > + > +#define _GNU_SOURCE > + > +#include > +#include > +#include > +#include This include is not available on systems without libcap-devel or similar installed. I suggest you compile this test conditional. A similar mechanism is implemented for libaio-devel (HAVE_LIBAIO). > +#include > +#include > + > +#include "tst_test.h" > + > +static const char* chroot_dir = "chroot"; > +static const char* new_root = "/new_root"; > +static const char* put_old = "/new_root/put_old"; > + > +// Test consists of a series of steps that allow pivot_root to succeed, which is > +// run when param is NORMAL. All other values tweak one of the steps to induce > +// a failure, and check the errno is as expected. > +#define NORMAL 0 > + > +// EBUSY > +// new_root or put_old are on the current root file system > +#define NEW_ROOT_ON_CURRENT_ROOT 1 > + > +// EINVAL > +// put_old is not underneath new_root > +// Note: if put_old and new_root are on the same fs, > +// pivot_root fails with EBUSY before testing reachability > +#define PUT_OLD_NOT_UNDERNEATH_NEW_ROOT 2 > + > +static const char* put_old_fs = "/put_old_fs"; > +static const char* put_old_bad = "/put_old_fs/put_old"; Even though these constants belong to this define, I would move them up to have all string constants defined in a single place. > + > +// ENOTDIR > +// new_root or put_old is not a directory > +#define PUT_OLD_NOT_DIR 3 > + > +// EPERM > +// The calling process does not have the CAP_SYS_ADMIN capability. > +#define NO_CAP_SYS_ADMIN 4 > + > +#define TEST_COUNT 5 == ARRAY_SIZE(expected_error) ... and can be defined directly in the tst_test struct. > + > +static int expected_error[] = { > + 0, > + EBUSY, > + EINVAL, > + ENOTDIR, > + EPERM, > +}; Maybe you are able to combine the defines, the documentation and this array into one array of testcase structs. (see e.g. testcases/kernel/syscalls/umount/umount02.c) That would be a bit more descriptive and easier to add more test cases. > + > +static void drop_cap_sys_admin(void) { braces > + cap_value_t cap_value[] = { CAP_SYS_ADMIN }; > + cap_t cap = cap_get_proc(); > + if (!cap) > + tst_brk(TFAIL | TERRNO, "cap_get_proc failed"); > + > + if (cap_set_flag(cap, CAP_EFFECTIVE, 1, cap_value, CAP_CLEAR)) > + tst_brk(TFAIL | TERRNO, "cap_set_flag failed"); > + > + if (cap_set_proc(cap)) > + tst_brk(TFAIL | TERRNO, "cap_set_proc failed"); > +} > + > +#ifdef HAVE_UNSHARE > +static void run(unsigned int param) 'param' is a bit bit generic, how about 'testcase' ? > +{ > + // Work in child process - needed to undo unshare and chroot > + if (SAFE_FORK()) { > + tst_reap_children(); > + return; > + } > + > + // pivot_root requires no shared mounts exist in process namespace > + TEST(unshare(CLONE_NEWNS | CLONE_FS)); > + if (TST_RET == -1) > + tst_brk(TFAIL | TERRNO, "unshare failed"); > + > + // Create an initial root dir. pivot_root doesn't work if the initial root > + // dir is a initramfs, so use chroot to create a safe environment > + SAFE_MOUNT("none", "/", NULL, MS_REC|MS_PRIVATE, NULL); > + SAFE_MOUNT("none", chroot_dir, "tmpfs", 0, 0); > + SAFE_CHROOT(chroot_dir); > + > + // Create our new root location > + SAFE_MKDIR(new_root, 0777); > + > + // pivot_root only works if new_root is a mount point, so mount a tmpfs > + // unless testing for that fail mode > + if (param != NEW_ROOT_ON_CURRENT_ROOT) > + SAFE_MOUNT("none", new_root, "tmpfs", 0, 0); > + > + // Create put_old under new_root, unless testing for that specific fail > + // mode > + const char* actual_put_old = NULL; > + if (param == PUT_OLD_NOT_UNDERNEATH_NEW_ROOT) { > + actual_put_old = put_old_bad; > + SAFE_MKDIR(put_old_fs, 0777); > + SAFE_MOUNT("none", put_old_fs, "tmpfs", 0, 0); > + SAFE_MKDIR(put_old_bad, 0777); > + } else { > + actual_put_old = put_old; > + > + // put_old must be a directory for success > + if (param == PUT_OLD_NOT_DIR) > + SAFE_CREAT(put_old, 0777); > + else > + SAFE_MKDIR(put_old, 0777); > + } > + > + if (param == NO_CAP_SYS_ADMIN) > + drop_cap_sys_admin(); > + > + // Test the syscall > + TEST(syscall(__NR_pivot_root, new_root, actual_put_old)); > + > + // If NORMAL it should have succeeded > + if (param == NORMAL) { > + if (TST_RET) { > + tst_res(TFAIL | TERRNO, "pivot_root failed"); > + exit(TBROK); > + } else { > + tst_res(TPASS, "pivot_root succeeded"); > + exit(TPASS); > + } > + } > + > + // pivot_root is expected to fail > + if (TST_RET == 0) { > + tst_res(TFAIL, "pivot_root succeeded unexpectedly"); > + exit(TBROK); > + } > + > + // Check error code is correct > + if (errno != expected_error[param]) { > + tst_res(TFAIL | TERRNO, "pivot_root failed with wrong errno"); > + exit(TBROK); > + } > + > + tst_res(TPASS, "pivot_root failed as expected with %s", > + strerror(errno)); > + exit(TPASS); > +} > + > +#else > +static void run(void) > +{ > + tst_brk(TCONF, NULL, "unshare is undefined."); > +} > +#endif > + > +static void setup(void) > +{ > + SAFE_MKDIR(chroot_dir, 0777); > +} > + > +static struct tst_test test = { > + .test = run, > + .tcnt = TEST_COUNT, > + .needs_tmpdir = 1, > + .needs_root = 1, > + .forks_child = 1, > + .setup = setup, > +}; > -- > 2.21.0.352.gf09ad66450-goog Thanks for addressing all the previous comments! -- Cheers, Matthias