From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Vorel Date: Tue, 19 Mar 2019 10:11:36 +0100 Subject: [LTP] [ltp][PATCH v3] Add ltp pivot_root test In-Reply-To: <20190305184455.93440-1-paullawrence@google.com> References: <20190305184455.93440-1-paullawrence@google.com> Message-ID: <20190319091136.GC26794@dell5510> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hi Paul, > Fixed too long line > Added const to static struct test_case > Made fail with TCONF when HAVE_LIBCAP not defined > Signed-off-by: Paul Lawrence > --- LGTM, with some cleanup below. Kind regards, Petr ... > +++ b/testcases/kernel/syscalls/pivot_root/pivot_root01.c > @@ -0,0 +1,200 @@ > +/* > + * SPDX-License-Identifier: GPL-2.0-or-later > + * > + * Copyright (c) 2019 Google, Inc. > + */ nit: correct form is to have SPDX at the first line, otherwise checkpatch.pl (from kernel) complains. // SPDX-License-Identifier: GPL-2.0-or-later > + > +#define _GNU_SOURCE > + > +#include nit: please use #include "config.h" > + > +#include > +#include > +#include > + > +#include > +#include > + > +#include "tst_test.h" > + > +#ifdef HAVE_LIBCAP > +#include > +#endif > + > +static const char* chroot_dir = "chroot"; > +static const char* new_root = "/new_root"; > +static const char* put_old = "/new_root/put_old"; > +static const char* put_old_fs = "/put_old_fs"; > +static const char* put_old_bad = "/put_old_fs/put_old"; nit: can you please use 'char *foo' instead of 'char* foo'? When actual variable is not needed I'd use definitions #define CHROOT_DIR "chroot" ... > + > +/* > + * 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 > + > +/* > + * 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 We usually use enum for it (see ppoll01.c). > + > +static const struct test_case { > + int test_case; > + int expected_error; > +} test_cases[] = { > + {NORMAL, 0}, > + {NEW_ROOT_ON_CURRENT_ROOT, EBUSY}, > + {PUT_OLD_NOT_UNDERNEATH_NEW_ROOT, EINVAL}, > + {PUT_OLD_NOT_DIR, ENOTDIR}, > + {NO_CAP_SYS_ADMIN, EPERM}, > +}; > + > +#ifdef HAVE_LIBCAP > +static void drop_cap_sys_admin(void) > +{ > + 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"); > +} > +#endif > + > +#ifdef HAVE_UNSHARE > +static void run(unsigned int test_case) > +{ > + /* 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 (test_cases[test_case].test_case != 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 (test_cases[test_case].test_case == 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 (test_cases[test_case].test_case == PUT_OLD_NOT_DIR) > + SAFE_CREAT(put_old, 0777); > + else > + SAFE_MKDIR(put_old, 0777); > + } > + > + if (test_cases[test_case].test_case == NO_CAP_SYS_ADMIN) > +#ifdef HAVE_LIBCAP > + drop_cap_sys_admin(); > +#else > + tst_brk(TCONF, > + "System doesn't have POSIX capabilities support"); > +#endif > + > + /* Test the syscall */ nit: I'd be for removing this and other comments (it's obvious). > + TEST(syscall(__NR_pivot_root, new_root, actual_put_old)); > + > + /* If NORMAL it should have succeeded */ > + if (test_cases[test_case].test_case == 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 != test_cases[test_case].expected_error) { > + 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."); Here NULL is copy paste error (that cleanup parameter is from legacy API, here suppress the message). We use TST_TEST_TCONF for cases like this. + Please guard everything, otherwise we get "defined but not used". > +} > +#endif > + > +static void setup(void) > +{ > + SAFE_MKDIR(chroot_dir, 0777); > +} > + > +static struct tst_test test = { > + .test = run, > + .tcnt = ARRAY_SIZE(test_cases), > + .needs_tmpdir = 1, > + .needs_root = 1, > + .forks_child = 1, > + .setup = setup, > +}; Kind regards, Petr