lkml.org 
[lkml]   [2019]   [Nov]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v15 8/9] selftests: add openat2(2) selftests
    Date
    Test all of the various openat2(2) flags. A small stress-test of a
    symlink-rename attack is included to show that the protections against
    ".."-based attacks are sufficient.

    The main things these self-tests are enforcing are:

    * The struct+usize ABI for openat2(2) and copy_struct_from_user() to
    ensure that upgrades will be handled gracefully (in addition,
    ensuring that misaligned structures are also handled correctly).

    * The -EINVAL checks for openat2(2) are all correctly handled to avoid
    userspace passing unknown or conflicting flag sets (most
    importantly, ensuring that invalid flag combinations are checked).

    * All of the RESOLVE_* semantics (including errno values) are
    correctly handled with various combinations of paths and flags.

    * RESOLVE_IN_ROOT correctly protects against the symlink rename(2)
    attack that has been responsible for several CVEs (and likely will
    be responsible for several more).

    Cc: Shuah Khan <shuah@kernel.org>
    Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
    ---
    tools/testing/selftests/Makefile | 1 +
    tools/testing/selftests/openat2/.gitignore | 1 +
    tools/testing/selftests/openat2/Makefile | 8 +
    tools/testing/selftests/openat2/helpers.c | 109 ++++
    tools/testing/selftests/openat2/helpers.h | 107 ++++
    .../testing/selftests/openat2/openat2_test.c | 316 +++++++++++
    .../selftests/openat2/rename_attack_test.c | 160 ++++++
    .../testing/selftests/openat2/resolve_test.c | 523 ++++++++++++++++++
    8 files changed, 1225 insertions(+)
    create mode 100644 tools/testing/selftests/openat2/.gitignore
    create mode 100644 tools/testing/selftests/openat2/Makefile
    create mode 100644 tools/testing/selftests/openat2/helpers.c
    create mode 100644 tools/testing/selftests/openat2/helpers.h
    create mode 100644 tools/testing/selftests/openat2/openat2_test.c
    create mode 100644 tools/testing/selftests/openat2/rename_attack_test.c
    create mode 100644 tools/testing/selftests/openat2/resolve_test.c

    diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
    index 4cdbae6f4e61..28996856ed5e 100644
    --- a/tools/testing/selftests/Makefile
    +++ b/tools/testing/selftests/Makefile
    @@ -37,6 +37,7 @@ TARGETS += powerpc
    TARGETS += proc
    TARGETS += pstore
    TARGETS += ptrace
    +TARGETS += openat2
    TARGETS += rseq
    TARGETS += rtc
    TARGETS += seccomp
    diff --git a/tools/testing/selftests/openat2/.gitignore b/tools/testing/selftests/openat2/.gitignore
    new file mode 100644
    index 000000000000..bd68f6c3fd07
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/.gitignore
    @@ -0,0 +1 @@
    +/*_test
    diff --git a/tools/testing/selftests/openat2/Makefile b/tools/testing/selftests/openat2/Makefile
    new file mode 100644
    index 000000000000..4b93b1417b86
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/Makefile
    @@ -0,0 +1,8 @@
    +# SPDX-License-Identifier: GPL-2.0-or-later
    +
    +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined
    +TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test
    +
    +include ../lib.mk
    +
    +$(TEST_GEN_PROGS): helpers.c
    diff --git a/tools/testing/selftests/openat2/helpers.c b/tools/testing/selftests/openat2/helpers.c
    new file mode 100644
    index 000000000000..e9a6557ab16f
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/helpers.c
    @@ -0,0 +1,109 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * Author: Aleksa Sarai <cyphar@cyphar.com>
    + * Copyright (C) 2018-2019 SUSE LLC.
    + */
    +
    +#define _GNU_SOURCE
    +#include <errno.h>
    +#include <fcntl.h>
    +#include <stdbool.h>
    +#include <string.h>
    +#include <syscall.h>
    +#include <limits.h>
    +
    +#include "helpers.h"
    +
    +bool needs_openat2(const struct open_how *how)
    +{
    + return how->resolve != 0;
    +}
    +
    +int raw_openat2(int dfd, const char *path, void *how, size_t size)
    +{
    + int ret = syscall(__NR_openat2, dfd, path, how, size);
    + return ret >= 0 ? ret : -errno;
    +}
    +
    +int sys_openat2(int dfd, const char *path, struct open_how *how)
    +{
    + return raw_openat2(dfd, path, how, sizeof(*how));
    +}
    +
    +int sys_openat(int dfd, const char *path, struct open_how *how)
    +{
    + int ret = openat(dfd, path, how->flags, how->mode);
    + return ret >= 0 ? ret : -errno;
    +}
    +
    +int sys_renameat2(int olddirfd, const char *oldpath,
    + int newdirfd, const char *newpath, unsigned int flags)
    +{
    + int ret = syscall(__NR_renameat2, olddirfd, oldpath,
    + newdirfd, newpath, flags);
    + return ret >= 0 ? ret : -errno;
    +}
    +
    +int touchat(int dfd, const char *path)
    +{
    + int fd = openat(dfd, path, O_CREAT);
    + if (fd >= 0)
    + close(fd);
    + return fd;
    +}
    +
    +char *fdreadlink(int fd)
    +{
    + char *target, *tmp;
    +
    + E_asprintf(&tmp, "/proc/self/fd/%d", fd);
    +
    + target = malloc(PATH_MAX);
    + if (!target)
    + ksft_exit_fail_msg("fdreadlink: malloc failed\n");
    + memset(target, 0, PATH_MAX);
    +
    + E_readlink(tmp, target, PATH_MAX);
    + free(tmp);
    + return target;
    +}
    +
    +bool fdequal(int fd, int dfd, const char *path)
    +{
    + char *fdpath, *dfdpath, *other;
    + bool cmp;
    +
    + fdpath = fdreadlink(fd);
    + dfdpath = fdreadlink(dfd);
    +
    + if (!path)
    + E_asprintf(&other, "%s", dfdpath);
    + else if (*path == '/')
    + E_asprintf(&other, "%s", path);
    + else
    + E_asprintf(&other, "%s/%s", dfdpath, path);
    +
    + cmp = !strcmp(fdpath, other);
    +
    + free(fdpath);
    + free(dfdpath);
    + free(other);
    + return cmp;
    +}
    +
    +bool openat2_supported = false;
    +
    +void __attribute__((constructor)) init(void)
    +{
    + struct open_how how = {};
    + int fd;
    +
    + BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_VER0);
    +
    + /* Check openat2(2) support. */
    + fd = sys_openat2(AT_FDCWD, ".", &how);
    + openat2_supported = (fd >= 0);
    +
    + if (fd >= 0)
    + close(fd);
    +}
    diff --git a/tools/testing/selftests/openat2/helpers.h b/tools/testing/selftests/openat2/helpers.h
    new file mode 100644
    index 000000000000..43ca5ceab6e3
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/helpers.h
    @@ -0,0 +1,107 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * Author: Aleksa Sarai <cyphar@cyphar.com>
    + * Copyright (C) 2018-2019 SUSE LLC.
    + */
    +
    +#ifndef __RESOLVEAT_H__
    +#define __RESOLVEAT_H__
    +
    +#define _GNU_SOURCE
    +#include <stdint.h>
    +#include <errno.h>
    +#include <linux/types.h>
    +#include "../kselftest.h"
    +
    +#define ARRAY_LEN(X) (sizeof (X) / sizeof (*(X)))
    +#define BUILD_BUG_ON(e) ((void)(sizeof(struct { int:(-!!(e)); })))
    +
    +#ifndef SYS_openat2
    +#ifndef __NR_openat2
    +#define __NR_openat2 437
    +#endif /* __NR_openat2 */
    +#define SYS_openat2 __NR_openat2
    +#endif /* SYS_openat2 */
    +
    +/*
    + * Arguments for how openat2(2) should open the target path. If @resolve is
    + * zero, then openat2(2) operates very similarly to openat(2).
    + *
    + * However, unlike openat(2), unknown bits in @flags result in -EINVAL rather
    + * than being silently ignored. @mode must be zero unless one of {O_CREAT,
    + * O_TMPFILE} are set.
    + *
    + * @flags: O_* flags.
    + * @mode: O_CREAT/O_TMPFILE file mode.
    + * @resolve: RESOLVE_* flags.
    + */
    +struct open_how {
    + __aligned_u64 flags;
    + __u16 mode;
    + __u16 __padding[3]; /* must be zeroed */
    + __aligned_u64 resolve;
    +};
    +
    +#define OPEN_HOW_SIZE_VER0 24 /* sizeof first published struct */
    +#define OPEN_HOW_SIZE_LATEST OPEN_HOW_SIZE_VER0
    +
    +bool needs_openat2(const struct open_how *how);
    +
    +#ifndef RESOLVE_IN_ROOT
    +/* how->resolve flags for openat2(2). */
    +#define RESOLVE_NO_XDEV 0x01 /* Block mount-point crossings
    + (includes bind-mounts). */
    +#define RESOLVE_NO_MAGICLINKS 0x02 /* Block traversal through procfs-style
    + "magic-links". */
    +#define RESOLVE_NO_SYMLINKS 0x04 /* Block traversal through all symlinks
    + (implies OEXT_NO_MAGICLINKS) */
    +#define RESOLVE_BENEATH 0x08 /* Block "lexical" trickery like
    + "..", symlinks, and absolute
    + paths which escape the dirfd. */
    +#define RESOLVE_IN_ROOT 0x10 /* Make all jumps to "/" and ".."
    + be scoped inside the dirfd
    + (similar to chroot(2)). */
    +#endif /* RESOLVE_IN_ROOT */
    +
    +#define E_func(func, ...) \
    + do { \
    + if (func(__VA_ARGS__) < 0) \
    + ksft_exit_fail_msg("%s:%d %s failed\n", \
    + __FILE__, __LINE__, #func);\
    + } while (0)
    +
    +#define E_asprintf(...) E_func(asprintf, __VA_ARGS__)
    +#define E_chmod(...) E_func(chmod, __VA_ARGS__)
    +#define E_dup2(...) E_func(dup2, __VA_ARGS__)
    +#define E_fchdir(...) E_func(fchdir, __VA_ARGS__)
    +#define E_fstatat(...) E_func(fstatat, __VA_ARGS__)
    +#define E_kill(...) E_func(kill, __VA_ARGS__)
    +#define E_mkdirat(...) E_func(mkdirat, __VA_ARGS__)
    +#define E_mount(...) E_func(mount, __VA_ARGS__)
    +#define E_prctl(...) E_func(prctl, __VA_ARGS__)
    +#define E_readlink(...) E_func(readlink, __VA_ARGS__)
    +#define E_setresuid(...) E_func(setresuid, __VA_ARGS__)
    +#define E_symlinkat(...) E_func(symlinkat, __VA_ARGS__)
    +#define E_touchat(...) E_func(touchat, __VA_ARGS__)
    +#define E_unshare(...) E_func(unshare, __VA_ARGS__)
    +
    +#define E_assert(expr, msg, ...) \
    + do { \
    + if (!(expr)) \
    + ksft_exit_fail_msg("ASSERT(%s:%d) failed (%s): " msg "\n", \
    + __FILE__, __LINE__, #expr, ##__VA_ARGS__); \
    + } while (0)
    +
    +int raw_openat2(int dfd, const char *path, void *how, size_t size);
    +int sys_openat2(int dfd, const char *path, struct open_how *how);
    +int sys_openat(int dfd, const char *path, struct open_how *how);
    +int sys_renameat2(int olddirfd, const char *oldpath,
    + int newdirfd, const char *newpath, unsigned int flags);
    +
    +int touchat(int dfd, const char *path);
    +char *fdreadlink(int fd);
    +bool fdequal(int fd, int dfd, const char *path);
    +
    +extern bool openat2_supported;
    +
    +#endif /* __RESOLVEAT_H__ */
    diff --git a/tools/testing/selftests/openat2/openat2_test.c b/tools/testing/selftests/openat2/openat2_test.c
    new file mode 100644
    index 000000000000..8a641acb0d6c
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/openat2_test.c
    @@ -0,0 +1,316 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * Author: Aleksa Sarai <cyphar@cyphar.com>
    + * Copyright (C) 2018-2019 SUSE LLC.
    + */
    +
    +#define _GNU_SOURCE
    +#include <fcntl.h>
    +#include <sched.h>
    +#include <sys/stat.h>
    +#include <sys/types.h>
    +#include <sys/mount.h>
    +#include <stdlib.h>
    +#include <stdbool.h>
    +#include <string.h>
    +
    +#include "../kselftest.h"
    +#include "helpers.h"
    +
    +/*
    + * O_LARGEFILE is set to 0 by glibc.
    + * XXX: This is wrong on {mips, parisc, powerpc, sparc}.
    + */
    +#undef O_LARGEFILE
    +#define O_LARGEFILE 0x8000
    +
    +struct open_how_ext {
    + struct open_how inner;
    + uint32_t extra1;
    + char pad1[128];
    + uint32_t extra2;
    + char pad2[128];
    + uint32_t extra3;
    +};
    +
    +struct struct_test {
    + const char *name;
    + struct open_how_ext arg;
    + size_t size;
    + int err;
    +};
    +
    +#define NUM_OPENAT2_STRUCT_TESTS 9
    +#define NUM_OPENAT2_STRUCT_VARIATIONS 13
    +
    +void test_openat2_struct(void)
    +{
    + int misalignments[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 17, 87 };
    +
    + struct struct_test tests[] = {
    + /* Normal struct. */
    + { .name = "normal struct",
    + .arg.inner.flags = O_RDONLY,
    + .size = sizeof(struct open_how) },
    + /* Bigger struct, with zeroed out end. */
    + { .name = "bigger struct (zeroed out)",
    + .arg.inner.flags = O_RDONLY,
    + .size = sizeof(struct open_how_ext) },
    +
    + /* Normal struct with broken padding. */
    + { .name = "normal struct (non-zero padding[0])",
    + .arg.inner.flags = O_RDONLY,
    + .arg.inner.__padding = {0xa0, 0x00},
    + .size = sizeof(struct open_how_ext), .err = -EINVAL },
    + { .name = "normal struct (non-zero padding[1])",
    + .arg.inner.flags = O_RDONLY,
    + .arg.inner.__padding = {0x00, 0x1a},
    + .size = sizeof(struct open_how_ext), .err = -EINVAL },
    +
    + /* TODO: Once expanded, check zero-padding. */
    +
    + /* Smaller than version-0 struct. */
    + { .name = "zero-sized 'struct'",
    + .arg.inner.flags = O_RDONLY, .size = 0, .err = -EINVAL },
    + { .name = "smaller-than-v0 struct",
    + .arg.inner.flags = O_RDONLY,
    + .size = OPEN_HOW_SIZE_VER0 - 1, .err = -EINVAL },
    +
    + /* Bigger struct, with non-zero trailing bytes. */
    + { .name = "bigger struct (non-zero data in first 'future field')",
    + .arg.inner.flags = O_RDONLY, .arg.extra1 = 0xdeadbeef,
    + .size = sizeof(struct open_how_ext), .err = -E2BIG },
    + { .name = "bigger struct (non-zero data in middle of 'future fields')",
    + .arg.inner.flags = O_RDONLY, .arg.extra2 = 0xfeedcafe,
    + .size = sizeof(struct open_how_ext), .err = -E2BIG },
    + { .name = "bigger struct (non-zero data at end of 'future fields')",
    + .arg.inner.flags = O_RDONLY, .arg.extra3 = 0xabad1dea,
    + .size = sizeof(struct open_how_ext), .err = -E2BIG },
    + };
    +
    + BUILD_BUG_ON(ARRAY_LEN(misalignments) != NUM_OPENAT2_STRUCT_VARIATIONS);
    + BUILD_BUG_ON(ARRAY_LEN(tests) != NUM_OPENAT2_STRUCT_TESTS);
    +
    + for (int i = 0; i < ARRAY_LEN(tests); i++) {
    + struct struct_test *test = &tests[i];
    + struct open_how_ext how_ext = test->arg;
    +
    + for (int j = 0; j < ARRAY_LEN(misalignments); j++) {
    + int fd, misalign = misalignments[j];
    + char *fdpath = NULL;
    + bool failed;
    + void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
    +
    + void *copy = NULL, *how_copy = &how_ext;
    +
    + if (!openat2_supported) {
    + ksft_print_msg("openat2(2) unsupported\n");
    + resultfn = ksft_test_result_skip;
    + goto skip;
    + }
    +
    + if (misalign) {
    + /*
    + * Explicitly misalign the structure copying it with the given
    + * (mis)alignment offset. The other data is set to be non-zero to
    + * make sure that non-zero bytes outside the struct aren't checked
    + *
    + * This is effectively to check that is_zeroed_user() works.
    + */
    + copy = malloc(misalign + sizeof(how_ext));
    + how_copy = copy + misalign;
    + memset(copy, 0xff, misalign);
    + memcpy(how_copy, &how_ext, sizeof(how_ext));
    + }
    +
    + fd = raw_openat2(AT_FDCWD, ".", how_copy, test->size);
    + if (test->err >= 0)
    + failed = (fd < 0);
    + else
    + failed = (fd != test->err);
    + if (fd >= 0) {
    + fdpath = fdreadlink(fd);
    + close(fd);
    + }
    +
    + if (failed) {
    + resultfn = ksft_test_result_fail;
    +
    + ksft_print_msg("openat2 unexpectedly returned ");
    + if (fdpath)
    + ksft_print_msg("%d['%s']\n", fd, fdpath);
    + else
    + ksft_print_msg("%d (%s)\n", fd, strerror(-fd));
    + }
    +
    +skip:
    + if (test->err >= 0)
    + resultfn("openat2 with %s argument [misalign=%d] succeeds\n",
    + test->name, misalign);
    + else
    + resultfn("openat2 with %s argument [misalign=%d] fails with %d (%s)\n",
    + test->name, misalign, test->err,
    + strerror(-test->err));
    +
    + free(copy);
    + free(fdpath);
    + fflush(stdout);
    + }
    + }
    +}
    +
    +struct flag_test {
    + const char *name;
    + struct open_how how;
    + int err;
    +};
    +
    +#define NUM_OPENAT2_FLAG_TESTS 21
    +
    +void test_openat2_flags(void)
    +{
    + struct flag_test tests[] = {
    + /* O_TMPFILE is incompatible with O_PATH and O_CREAT. */
    + { .name = "incompatible flags (O_TMPFILE | O_PATH)",
    + .how.flags = O_TMPFILE | O_PATH | O_RDWR, .err = -EINVAL },
    + { .name = "incompatible flags (O_TMPFILE | O_CREAT)",
    + .how.flags = O_TMPFILE | O_CREAT | O_RDWR, .err = -EINVAL },
    +
    + /* O_PATH only permits certain other flags to be set ... */
    + { .name = "compatible flags (O_PATH | O_CLOEXEC)",
    + .how.flags = O_PATH | O_CLOEXEC },
    + { .name = "compatible flags (O_PATH | O_DIRECTORY)",
    + .how.flags = O_PATH | O_DIRECTORY },
    + { .name = "compatible flags (O_PATH | O_NOFOLLOW)",
    + .how.flags = O_PATH | O_NOFOLLOW },
    + /* ... and others are absolutely not permitted. */
    + { .name = "incompatible flags (O_PATH | O_RDWR)",
    + .how.flags = O_PATH | O_RDWR, .err = -EINVAL },
    + { .name = "incompatible flags (O_PATH | O_CREAT)",
    + .how.flags = O_PATH | O_CREAT, .err = -EINVAL },
    + { .name = "incompatible flags (O_PATH | O_EXCL)",
    + .how.flags = O_PATH | O_EXCL, .err = -EINVAL },
    + { .name = "incompatible flags (O_PATH | O_NOCTTY)",
    + .how.flags = O_PATH | O_NOCTTY, .err = -EINVAL },
    + { .name = "incompatible flags (O_PATH | O_DIRECT)",
    + .how.flags = O_PATH | O_DIRECT, .err = -EINVAL },
    + { .name = "incompatible flags (O_PATH | O_LARGEFILE)",
    + .how.flags = O_PATH | O_LARGEFILE, .err = -EINVAL },
    +
    + /* ->mode must only be set with O_{CREAT,TMPFILE}. */
    + { .name = "non-zero how.mode and O_RDONLY",
    + .how.flags = O_RDONLY, .how.mode = 0600, .err = -EINVAL },
    + { .name = "non-zero how.mode and O_PATH",
    + .how.flags = O_PATH, .how.mode = 0600, .err = -EINVAL },
    + { .name = "valid how.mode and O_CREAT",
    + .how.flags = O_CREAT, .how.mode = 0600 },
    + { .name = "valid how.mode and O_TMPFILE",
    + .how.flags = O_TMPFILE | O_RDWR, .how.mode = 0600 },
    + /* ->mode must only contain 0777 bits. */
    + { .name = "invalid how.mode and O_CREAT",
    + .how.flags = O_CREAT,
    + .how.mode = 0xFFFF, .err = -EINVAL },
    + { .name = "invalid how.mode and O_TMPFILE",
    + .how.flags = O_TMPFILE | O_RDWR,
    + .how.mode = 0x1337, .err = -EINVAL },
    +
    + /* ->resolve must only contain RESOLVE_* flags. */
    + { .name = "invalid how.resolve and O_RDONLY",
    + .how.flags = O_RDONLY,
    + .how.resolve = 0x1337, .err = -EINVAL },
    + { .name = "invalid how.resolve and O_CREAT",
    + .how.flags = O_CREAT,
    + .how.resolve = 0x1337, .err = -EINVAL },
    + { .name = "invalid how.resolve and O_TMPFILE",
    + .how.flags = O_TMPFILE | O_RDWR,
    + .how.resolve = 0x1337, .err = -EINVAL },
    + { .name = "invalid how.resolve and O_PATH",
    + .how.flags = O_PATH,
    + .how.resolve = 0x1337, .err = -EINVAL },
    + };
    +
    + BUILD_BUG_ON(ARRAY_LEN(tests) != NUM_OPENAT2_FLAG_TESTS);
    +
    + for (int i = 0; i < ARRAY_LEN(tests); i++) {
    + int fd, fdflags = -1;
    + char *path, *fdpath = NULL;
    + bool failed = false;
    + struct flag_test *test = &tests[i];
    + void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
    +
    + if (!openat2_supported) {
    + ksft_print_msg("openat2(2) unsupported\n");
    + resultfn = ksft_test_result_skip;
    + goto skip;
    + }
    +
    + path = (test->how.flags & O_CREAT) ? "/tmp/ksft.openat2_tmpfile" : ".";
    + unlink(path);
    +
    + fd = sys_openat2(AT_FDCWD, path, &test->how);
    + if (test->err >= 0)
    + failed = (fd < 0);
    + else
    + failed = (fd != test->err);
    + if (fd >= 0) {
    + int otherflags;
    +
    + fdpath = fdreadlink(fd);
    + fdflags = fcntl(fd, F_GETFL);
    + otherflags = fcntl(fd, F_GETFD);
    + close(fd);
    +
    + E_assert(fdflags >= 0, "fcntl F_GETFL of new fd");
    + E_assert(otherflags >= 0, "fcntl F_GETFD of new fd");
    +
    + /* O_CLOEXEC isn't shown in F_GETFL. */
    + if (otherflags & FD_CLOEXEC)
    + fdflags |= O_CLOEXEC;
    + /* O_CREAT is hidden from F_GETFL. */
    + if (test->how.flags & O_CREAT)
    + fdflags |= O_CREAT;
    + if (!(test->how.flags & O_LARGEFILE))
    + fdflags &= ~O_LARGEFILE;
    + failed |= (fdflags != test->how.flags);
    + }
    +
    + if (failed) {
    + resultfn = ksft_test_result_fail;
    +
    + ksft_print_msg("openat2 unexpectedly returned ");
    + if (fdpath)
    + ksft_print_msg("%d['%s'] with %X (!= %X)\n",
    + fd, fdpath, fdflags,
    + test->how.flags);
    + else
    + ksft_print_msg("%d (%s)\n", fd, strerror(-fd));
    + }
    +
    +skip:
    + if (test->err >= 0)
    + resultfn("openat2 with %s succeeds\n", test->name);
    + else
    + resultfn("openat2 with %s fails with %d (%s)\n",
    + test->name, test->err, strerror(-test->err));
    +
    + free(fdpath);
    + fflush(stdout);
    + }
    +}
    +
    +#define NUM_TESTS (NUM_OPENAT2_STRUCT_VARIATIONS * NUM_OPENAT2_STRUCT_TESTS + \
    + NUM_OPENAT2_FLAG_TESTS)
    +
    +int main(int argc, char **argv)
    +{
    + ksft_print_header();
    + ksft_set_plan(NUM_TESTS);
    +
    + test_openat2_struct();
    + test_openat2_flags();
    +
    + if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
    + ksft_exit_fail();
    + else
    + ksft_exit_pass();
    +}
    diff --git a/tools/testing/selftests/openat2/rename_attack_test.c b/tools/testing/selftests/openat2/rename_attack_test.c
    new file mode 100644
    index 000000000000..0a770728b436
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/rename_attack_test.c
    @@ -0,0 +1,160 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * Author: Aleksa Sarai <cyphar@cyphar.com>
    + * Copyright (C) 2018-2019 SUSE LLC.
    + */
    +
    +#define _GNU_SOURCE
    +#include <errno.h>
    +#include <fcntl.h>
    +#include <sched.h>
    +#include <sys/stat.h>
    +#include <sys/types.h>
    +#include <sys/mount.h>
    +#include <sys/mman.h>
    +#include <sys/prctl.h>
    +#include <signal.h>
    +#include <stdio.h>
    +#include <stdlib.h>
    +#include <stdbool.h>
    +#include <string.h>
    +#include <syscall.h>
    +#include <limits.h>
    +#include <unistd.h>
    +
    +#include "../kselftest.h"
    +#include "helpers.h"
    +
    +/* Construct a test directory with the following structure:
    + *
    + * root/
    + * |-- a/
    + * | `-- c/
    + * `-- b/
    + */
    +int setup_testdir(void)
    +{
    + int dfd;
    + char dirname[] = "/tmp/ksft-openat2-rename-attack.XXXXXX";
    +
    + /* Make the top-level directory. */
    + if (!mkdtemp(dirname))
    + ksft_exit_fail_msg("setup_testdir: failed to create tmpdir\n");
    + dfd = open(dirname, O_PATH | O_DIRECTORY);
    + if (dfd < 0)
    + ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
    +
    + E_mkdirat(dfd, "a", 0755);
    + E_mkdirat(dfd, "b", 0755);
    + E_mkdirat(dfd, "a/c", 0755);
    +
    + return dfd;
    +}
    +
    +/* Swap @dirfd/@a and @dirfd/@b constantly. Parent must kill this process. */
    +pid_t spawn_attack(int dirfd, char *a, char *b)
    +{
    + pid_t child = fork();
    + if (child != 0)
    + return child;
    +
    + /* If the parent (the test process) dies, kill ourselves too. */
    + E_prctl(PR_SET_PDEATHSIG, SIGKILL);
    +
    + /* Swap @a and @b. */
    + for (;;)
    + renameat2(dirfd, a, dirfd, b, RENAME_EXCHANGE);
    + exit(1);
    +}
    +
    +#define NUM_RENAME_TESTS 2
    +#define ROUNDS 400000
    +
    +const char *flagname(int resolve)
    +{
    + switch (resolve) {
    + case RESOLVE_IN_ROOT:
    + return "RESOLVE_IN_ROOT";
    + case RESOLVE_BENEATH:
    + return "RESOLVE_BENEATH";
    + }
    + return "(unknown)";
    +}
    +
    +void test_rename_attack(int resolve)
    +{
    + int dfd, afd;
    + pid_t child;
    + void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
    + int escapes = 0, other_errs = 0, exdevs = 0, eagains = 0, successes = 0;
    +
    + struct open_how how = {
    + .flags = O_PATH,
    + .resolve = resolve,
    + };
    +
    + if (!openat2_supported) {
    + how.resolve = 0;
    + ksft_print_msg("openat2(2) unsupported -- using openat(2) instead\n");
    + }
    +
    + dfd = setup_testdir();
    + afd = openat(dfd, "a", O_PATH);
    + if (afd < 0)
    + ksft_exit_fail_msg("test_rename_attack: failed to open 'a'\n");
    +
    + child = spawn_attack(dfd, "a/c", "b");
    +
    + for (int i = 0; i < ROUNDS; i++) {
    + int fd;
    + char *victim_path = "c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../..";
    +
    + if (openat2_supported)
    + fd = sys_openat2(afd, victim_path, &how);
    + else
    + fd = sys_openat(afd, victim_path, &how);
    +
    + if (fd < 0) {
    + if (fd == -EAGAIN)
    + eagains++;
    + else if (fd == -EXDEV)
    + exdevs++;
    + else if (fd == -ENOENT)
    + escapes++; /* escaped outside and got ENOENT... */
    + else
    + other_errs++; /* unexpected error */
    + } else {
    + if (fdequal(fd, afd, NULL))
    + successes++;
    + else
    + escapes++; /* we got an unexpected fd */
    + }
    + close(fd);
    + }
    +
    + if (escapes > 0)
    + resultfn = ksft_test_result_fail;
    + ksft_print_msg("non-escapes: EAGAIN=%d EXDEV=%d E<other>=%d success=%d\n",
    + eagains, exdevs, other_errs, successes);
    + resultfn("rename attack with %s (%d runs, got %d escapes)\n",
    + flagname(resolve), ROUNDS, escapes);
    +
    + /* Should be killed anyway, but might as well make sure. */
    + E_kill(child, SIGKILL);
    +}
    +
    +#define NUM_TESTS NUM_RENAME_TESTS
    +
    +int main(int argc, char **argv)
    +{
    + ksft_print_header();
    + ksft_set_plan(NUM_TESTS);
    +
    + test_rename_attack(RESOLVE_BENEATH);
    + test_rename_attack(RESOLVE_IN_ROOT);
    +
    + if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
    + ksft_exit_fail();
    + else
    + ksft_exit_pass();
    +}
    diff --git a/tools/testing/selftests/openat2/resolve_test.c b/tools/testing/selftests/openat2/resolve_test.c
    new file mode 100644
    index 000000000000..7a94b1da8e7b
    --- /dev/null
    +++ b/tools/testing/selftests/openat2/resolve_test.c
    @@ -0,0 +1,523 @@
    +// SPDX-License-Identifier: GPL-2.0-or-later
    +/*
    + * Author: Aleksa Sarai <cyphar@cyphar.com>
    + * Copyright (C) 2018-2019 SUSE LLC.
    + */
    +
    +#define _GNU_SOURCE
    +#include <fcntl.h>
    +#include <sched.h>
    +#include <sys/stat.h>
    +#include <sys/types.h>
    +#include <sys/mount.h>
    +#include <stdlib.h>
    +#include <stdbool.h>
    +#include <string.h>
    +
    +#include "../kselftest.h"
    +#include "helpers.h"
    +
    +/*
    + * Construct a test directory with the following structure:
    + *
    + * root/
    + * |-- procexe -> /proc/self/exe
    + * |-- procroot -> /proc/self/root
    + * |-- root/
    + * |-- mnt/ [mountpoint]
    + * | |-- self -> ../mnt/
    + * | `-- absself -> /mnt/
    + * |-- etc/
    + * | `-- passwd
    + * |-- creatlink -> /newfile3
    + * |-- reletc -> etc/
    + * |-- relsym -> etc/passwd
    + * |-- absetc -> /etc/
    + * |-- abssym -> /etc/passwd
    + * |-- abscheeky -> /cheeky
    + * `-- cheeky/
    + * |-- absself -> /
    + * |-- self -> ../../root/
    + * |-- garbageself -> /../../root/
    + * |-- passwd -> ../cheeky/../cheeky/../etc/../etc/passwd
    + * |-- abspasswd -> /../cheeky/../cheeky/../etc/../etc/passwd
    + * |-- dotdotlink -> ../../../../../../../../../../../../../../etc/passwd
    + * `-- garbagelink -> /../../../../../../../../../../../../../../etc/passwd
    + */
    +int setup_testdir(void)
    +{
    + int dfd, tmpfd;
    + char dirname[] = "/tmp/ksft-openat2-testdir.XXXXXX";
    +
    + /* Unshare and make /tmp a new directory. */
    + E_unshare(CLONE_NEWNS);
    + E_mount("", "/tmp", "", MS_PRIVATE, "");
    +
    + /* Make the top-level directory. */
    + if (!mkdtemp(dirname))
    + ksft_exit_fail_msg("setup_testdir: failed to create tmpdir\n");
    + dfd = open(dirname, O_PATH | O_DIRECTORY);
    + if (dfd < 0)
    + ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
    +
    + /* A sub-directory which is actually used for tests. */
    + E_mkdirat(dfd, "root", 0755);
    + tmpfd = openat(dfd, "root", O_PATH | O_DIRECTORY);
    + if (tmpfd < 0)
    + ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
    + close(dfd);
    + dfd = tmpfd;
    +
    + E_symlinkat("/proc/self/exe", dfd, "procexe");
    + E_symlinkat("/proc/self/root", dfd, "procroot");
    + E_mkdirat(dfd, "root", 0755);
    +
    + /* There is no mountat(2), so use chdir. */
    + E_mkdirat(dfd, "mnt", 0755);
    + E_fchdir(dfd);
    + E_mount("tmpfs", "./mnt", "tmpfs", MS_NOSUID | MS_NODEV, "");
    + E_symlinkat("../mnt/", dfd, "mnt/self");
    + E_symlinkat("/mnt/", dfd, "mnt/absself");
    +
    + E_mkdirat(dfd, "etc", 0755);
    + E_touchat(dfd, "etc/passwd");
    +
    + E_symlinkat("/newfile3", dfd, "creatlink");
    + E_symlinkat("etc/", dfd, "reletc");
    + E_symlinkat("etc/passwd", dfd, "relsym");
    + E_symlinkat("/etc/", dfd, "absetc");
    + E_symlinkat("/etc/passwd", dfd, "abssym");
    + E_symlinkat("/cheeky", dfd, "abscheeky");
    +
    + E_mkdirat(dfd, "cheeky", 0755);
    +
    + E_symlinkat("/", dfd, "cheeky/absself");
    + E_symlinkat("../../root/", dfd, "cheeky/self");
    + E_symlinkat("/../../root/", dfd, "cheeky/garbageself");
    +
    + E_symlinkat("../cheeky/../etc/../etc/passwd", dfd, "cheeky/passwd");
    + E_symlinkat("/../cheeky/../etc/../etc/passwd", dfd, "cheeky/abspasswd");
    +
    + E_symlinkat("../../../../../../../../../../../../../../etc/passwd",
    + dfd, "cheeky/dotdotlink");
    + E_symlinkat("/../../../../../../../../../../../../../../etc/passwd",
    + dfd, "cheeky/garbagelink");
    +
    + return dfd;
    +}
    +
    +struct basic_test {
    + const char *name;
    + const char *dir;
    + const char *path;
    + struct open_how how;
    + bool pass;
    + union {
    + int err;
    + const char *path;
    + } out;
    +};
    +
    +#define NUM_OPENAT2_OPATH_TESTS 88
    +
    +void test_openat2_opath_tests(void)
    +{
    + int rootfd, hardcoded_fd;
    + char *procselfexe, *hardcoded_fdpath;
    +
    + E_asprintf(&procselfexe, "/proc/%d/exe", getpid());
    + rootfd = setup_testdir();
    +
    + hardcoded_fd = open("/dev/null", O_RDONLY);
    + E_assert(hardcoded_fd >= 0, "open fd to hardcode");
    + E_asprintf(&hardcoded_fdpath, "self/fd/%d", hardcoded_fd);
    +
    + struct basic_test tests[] = {
    + /** RESOLVE_BENEATH **/
    + /* Attempts to cross dirfd should be blocked. */
    + { .name = "[beneath] jump to /",
    + .path = "/", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] absolute link to $root",
    + .path = "cheeky/absself", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] chained absolute links to $root",
    + .path = "abscheeky/absself", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] jump outside $root",
    + .path = "..", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] temporary jump outside $root",
    + .path = "../root/", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] symlink temporary jump outside $root",
    + .path = "cheeky/self", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] chained symlink temporary jump outside $root",
    + .path = "abscheeky/self", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] garbage links to $root",
    + .path = "cheeky/garbageself", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] chained garbage links to $root",
    + .path = "abscheeky/garbageself", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + /* Only relative paths that stay inside dirfd should work. */
    + { .name = "[beneath] ordinary path to 'root'",
    + .path = "root", .how.resolve = RESOLVE_BENEATH,
    + .out.path = "root", .pass = true },
    + { .name = "[beneath] ordinary path to 'etc'",
    + .path = "etc", .how.resolve = RESOLVE_BENEATH,
    + .out.path = "etc", .pass = true },
    + { .name = "[beneath] ordinary path to 'etc/passwd'",
    + .path = "etc/passwd", .how.resolve = RESOLVE_BENEATH,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[beneath] relative symlink inside $root",
    + .path = "relsym", .how.resolve = RESOLVE_BENEATH,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[beneath] chained-'..' relative symlink inside $root",
    + .path = "cheeky/passwd", .how.resolve = RESOLVE_BENEATH,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[beneath] absolute symlink component outside $root",
    + .path = "abscheeky/passwd", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] absolute symlink target outside $root",
    + .path = "abssym", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] absolute path outside $root",
    + .path = "/etc/passwd", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] cheeky absolute path outside $root",
    + .path = "cheeky/abspasswd", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] chained cheeky absolute path outside $root",
    + .path = "abscheeky/abspasswd", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + /* Tricky paths should fail. */
    + { .name = "[beneath] tricky '..'-chained symlink outside $root",
    + .path = "cheeky/dotdotlink", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] tricky absolute + '..'-chained symlink outside $root",
    + .path = "abscheeky/dotdotlink", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] tricky garbage link outside $root",
    + .path = "cheeky/garbagelink", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[beneath] tricky absolute + garbage link outside $root",
    + .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_BENEATH,
    + .out.err = -EXDEV, .pass = false },
    +
    + /** RESOLVE_IN_ROOT **/
    + /* All attempts to cross the dirfd will be scoped-to-root. */
    + { .name = "[in_root] jump to /",
    + .path = "/", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = NULL, .pass = true },
    + { .name = "[in_root] absolute symlink to /root",
    + .path = "cheeky/absself", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = NULL, .pass = true },
    + { .name = "[in_root] chained absolute symlinks to /root",
    + .path = "abscheeky/absself", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = NULL, .pass = true },
    + { .name = "[in_root] '..' at root",
    + .path = "..", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = NULL, .pass = true },
    + { .name = "[in_root] '../root' at root",
    + .path = "../root/", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "root", .pass = true },
    + { .name = "[in_root] relative symlink containing '..' above root",
    + .path = "cheeky/self", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "root", .pass = true },
    + { .name = "[in_root] garbage link to /root",
    + .path = "cheeky/garbageself", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "root", .pass = true },
    + { .name = "[in_root] chainged garbage links to /root",
    + .path = "abscheeky/garbageself", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "root", .pass = true },
    + { .name = "[in_root] relative path to 'root'",
    + .path = "root", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "root", .pass = true },
    + { .name = "[in_root] relative path to 'etc'",
    + .path = "etc", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc", .pass = true },
    + { .name = "[in_root] relative path to 'etc/passwd'",
    + .path = "etc/passwd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] relative symlink to 'etc/passwd'",
    + .path = "relsym", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] chained-'..' relative symlink to 'etc/passwd'",
    + .path = "cheeky/passwd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] chained-'..' absolute + relative symlink to 'etc/passwd'",
    + .path = "abscheeky/passwd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] absolute symlink to 'etc/passwd'",
    + .path = "abssym", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] absolute path 'etc/passwd'",
    + .path = "/etc/passwd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] cheeky absolute path 'etc/passwd'",
    + .path = "cheeky/abspasswd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] chained cheeky absolute path 'etc/passwd'",
    + .path = "abscheeky/abspasswd", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky '..'-chained symlink outside $root",
    + .path = "cheeky/dotdotlink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky absolute + '..'-chained symlink outside $root",
    + .path = "abscheeky/dotdotlink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky absolute path + absolute + '..'-chained symlink outside $root",
    + .path = "/../../../../abscheeky/dotdotlink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky garbage link outside $root",
    + .path = "cheeky/garbagelink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky absolute + garbage link outside $root",
    + .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + { .name = "[in_root] tricky absolute path + absolute + garbage link outside $root",
    + .path = "/../../../../abscheeky/garbagelink", .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "etc/passwd", .pass = true },
    + /* O_CREAT should handle trailing symlinks correctly. */
    + { .name = "[in_root] O_CREAT of relative path inside $root",
    + .path = "newfile1", .how.flags = O_CREAT,
    + .how.mode = 0700,
    + .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "newfile1", .pass = true },
    + { .name = "[in_root] O_CREAT of absolute path",
    + .path = "/newfile2", .how.flags = O_CREAT,
    + .how.mode = 0700,
    + .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "newfile2", .pass = true },
    + { .name = "[in_root] O_CREAT of tricky symlink outside root",
    + .path = "/creatlink", .how.flags = O_CREAT,
    + .how.mode = 0700,
    + .how.resolve = RESOLVE_IN_ROOT,
    + .out.path = "newfile3", .pass = true },
    +
    + /** RESOLVE_NO_XDEV **/
    + /* Crossing *down* into a mountpoint is disallowed. */
    + { .name = "[no_xdev] cross into $mnt",
    + .path = "mnt", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] cross into $mnt/",
    + .path = "mnt/", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] cross into $mnt/.",
    + .path = "mnt/.", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + /* Crossing *up* out of a mountpoint is disallowed. */
    + { .name = "[no_xdev] goto mountpoint root",
    + .dir = "mnt", .path = ".", .how.resolve = RESOLVE_NO_XDEV,
    + .out.path = "mnt", .pass = true },
    + { .name = "[no_xdev] cross up through '..'",
    + .dir = "mnt", .path = "..", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] temporary cross up through '..'",
    + .dir = "mnt", .path = "../mnt", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] temporary relative symlink cross up",
    + .dir = "mnt", .path = "self", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] temporary absolute symlink cross up",
    + .dir = "mnt", .path = "absself", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + /* Jumping to "/" is ok, but later components cannot cross. */
    + { .name = "[no_xdev] jump to / directly",
    + .dir = "mnt", .path = "/", .how.resolve = RESOLVE_NO_XDEV,
    + .out.path = "/", .pass = true },
    + { .name = "[no_xdev] jump to / (from /) directly",
    + .dir = "/", .path = "/", .how.resolve = RESOLVE_NO_XDEV,
    + .out.path = "/", .pass = true },
    + { .name = "[no_xdev] jump to / then proc",
    + .path = "/proc/1", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] jump to / then tmp",
    + .path = "/tmp", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + /* Magic-links are blocked since they can switch vfsmounts. */
    + { .name = "[no_xdev] cross through magic-link to self/root",
    + .dir = "/proc", .path = "self/root", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + { .name = "[no_xdev] cross through magic-link to self/cwd",
    + .dir = "/proc", .path = "self/cwd", .how.resolve = RESOLVE_NO_XDEV,
    + .out.err = -EXDEV, .pass = false },
    + /* Except magic-link jumps inside the same vfsmount. */
    + { .name = "[no_xdev] jump through magic-link to same procfs",
    + .dir = "/proc", .path = hardcoded_fdpath, .how.resolve = RESOLVE_NO_XDEV,
    + .out.path = "/proc", .pass = true, },
    +
    + /** RESOLVE_NO_MAGICLINKS **/
    + /* Regular symlinks should work. */
    + { .name = "[no_magiclinks] ordinary relative symlink",
    + .path = "relsym", .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.path = "etc/passwd", .pass = true },
    + /* Magic-links should not work. */
    + { .name = "[no_magiclinks] symlink to magic-link",
    + .path = "procexe", .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_magiclinks] normal path to magic-link",
    + .path = "/proc/self/exe", .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_magiclinks] normal path to magic-link with O_NOFOLLOW",
    + .path = "/proc/self/exe", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.path = procselfexe, .pass = true },
    + { .name = "[no_magiclinks] symlink to magic-link path component",
    + .path = "procroot/etc", .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_magiclinks] magic-link path component",
    + .path = "/proc/self/root/etc", .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_magiclinks] magic-link path component with O_NOFOLLOW",
    + .path = "/proc/self/root/etc", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_MAGICLINKS,
    + .out.err = -ELOOP, .pass = false },
    +
    + /** RESOLVE_NO_SYMLINKS **/
    + /* Normal paths should work. */
    + { .name = "[no_symlinks] ordinary path to '.'",
    + .path = ".", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = NULL, .pass = true },
    + { .name = "[no_symlinks] ordinary path to 'root'",
    + .path = "root", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "root", .pass = true },
    + { .name = "[no_symlinks] ordinary path to 'etc'",
    + .path = "etc", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "etc", .pass = true },
    + { .name = "[no_symlinks] ordinary path to 'etc/passwd'",
    + .path = "etc/passwd", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "etc/passwd", .pass = true },
    + /* Regular symlinks are blocked. */
    + { .name = "[no_symlinks] relative symlink target",
    + .path = "relsym", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] relative symlink component",
    + .path = "reletc/passwd", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] absolute symlink target",
    + .path = "abssym", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] absolute symlink component",
    + .path = "absetc/passwd", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] cheeky garbage link",
    + .path = "cheeky/garbagelink", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] cheeky absolute + garbage link",
    + .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] cheeky absolute + absolute symlink",
    + .path = "abscheeky/absself", .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + /* Trailing symlinks with NO_FOLLOW. */
    + { .name = "[no_symlinks] relative symlink with O_NOFOLLOW",
    + .path = "relsym", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "relsym", .pass = true },
    + { .name = "[no_symlinks] absolute symlink with O_NOFOLLOW",
    + .path = "abssym", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "abssym", .pass = true },
    + { .name = "[no_symlinks] trailing symlink with O_NOFOLLOW",
    + .path = "cheeky/garbagelink", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.path = "cheeky/garbagelink", .pass = true },
    + { .name = "[no_symlinks] multiple symlink components with O_NOFOLLOW",
    + .path = "abscheeky/absself", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + { .name = "[no_symlinks] multiple symlink (and garbage link) components with O_NOFOLLOW",
    + .path = "abscheeky/garbagelink", .how.flags = O_NOFOLLOW,
    + .how.resolve = RESOLVE_NO_SYMLINKS,
    + .out.err = -ELOOP, .pass = false },
    + };
    +
    + BUILD_BUG_ON(ARRAY_LEN(tests) != NUM_OPENAT2_OPATH_TESTS);
    +
    + for (int i = 0; i < ARRAY_LEN(tests); i++) {
    + int dfd, fd;
    + char *fdpath = NULL;
    + bool failed;
    + void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
    + struct basic_test *test = &tests[i];
    +
    + if (!openat2_supported) {
    + ksft_print_msg("openat2(2) unsupported\n");
    + resultfn = ksft_test_result_skip;
    + goto skip;
    + }
    +
    + /* Auto-set O_PATH. */
    + if (!(test->how.flags & O_CREAT))
    + test->how.flags |= O_PATH;
    +
    + if (test->dir)
    + dfd = openat(rootfd, test->dir, O_PATH | O_DIRECTORY);
    + else
    + dfd = dup(rootfd);
    + E_assert(dfd, "failed to openat root '%s': %m", test->dir);
    +
    + E_dup2(dfd, hardcoded_fd);
    +
    + fd = sys_openat2(dfd, test->path, &test->how);
    + if (test->pass)
    + failed = (fd < 0 || !fdequal(fd, rootfd, test->out.path));
    + else
    + failed = (fd != test->out.err);
    + if (fd >= 0) {
    + fdpath = fdreadlink(fd);
    + close(fd);
    + }
    + close(dfd);
    +
    + if (failed) {
    + resultfn = ksft_test_result_fail;
    +
    + ksft_print_msg("openat2 unexpectedly returned ");
    + if (fdpath)
    + ksft_print_msg("%d['%s']\n", fd, fdpath);
    + else
    + ksft_print_msg("%d (%s)\n", fd, strerror(-fd));
    + }
    +
    +skip:
    + if (test->pass)
    + resultfn("%s gives path '%s'\n", test->name,
    + test->out.path ?: ".");
    + else
    + resultfn("%s fails with %d (%s)\n", test->name,
    + test->out.err, strerror(-test->out.err));
    +
    + fflush(stdout);
    + free(fdpath);
    + }
    +
    + free(procselfexe);
    + close(rootfd);
    +
    + free(hardcoded_fdpath);
    + close(hardcoded_fd);
    +}
    +
    +#define NUM_TESTS NUM_OPENAT2_OPATH_TESTS
    +
    +int main(int argc, char **argv)
    +{
    + ksft_print_header();
    + ksft_set_plan(NUM_TESTS);
    +
    + /* NOTE: We should be checking for CAP_SYS_ADMIN here... */
    + if (geteuid() != 0)
    + ksft_exit_skip("all tests require euid == 0\n");
    +
    + test_openat2_opath_tests();
    +
    + if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
    + ksft_exit_fail();
    + else
    + ksft_exit_pass();
    +}
    --
    2.23.0

    \
     
     \ /
      Last update: 2019-11-05 10:10    [W:3.294 / U:1.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site