[LTP] [PATCH v2 05/11] Add landlock01 test
Li Wang
liwang@redhat.com
Thu Jul 11 09:30:22 CEST 2024
On Thu, Jul 11, 2024 at 3:07 PM Andrea Cervesato <andrea.cervesato@suse.com>
wrote:
> Hi,
>
> On 7/11/24 05:16, Li Wang wrote:
>
> Hi Andrea,
>
> On Thu, Jul 11, 2024 at 2:02 AM Andrea Cervesato <andrea.cervesato@suse.de>
> wrote:
>
>> From: Andrea Cervesato <andrea.cervesato@suse.com>
>>
>> This test verifies that landlock_create_ruleset syscall fails with the
>> right error codes:
>>
>> - EINVAL Unknown flags, or unknown access, or too small size
>> - E2BIG size is too big
>> - EFAULT attr was not a valid address
>> - ENOMSG Empty accesses (i.e., attr->handled_access_fs is 0)
>>
>> Reviewed-by: Li Wang <liwang@redhat.com>
>> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
>> ---
>> runtest/syscalls | 2 +
>> testcases/kernel/syscalls/landlock/.gitignore | 1 +
>> testcases/kernel/syscalls/landlock/Makefile | 7 ++
>> testcases/kernel/syscalls/landlock/landlock01.c | 92
>> ++++++++++++++++++++++
>> .../kernel/syscalls/landlock/landlock_common.h | 74 +++++++++++++++++
>> 5 files changed, 176 insertions(+)
>>
>> diff --git a/runtest/syscalls b/runtest/syscalls
>> index b6cadb2df..667e419a3 100644
>> --- a/runtest/syscalls
>> +++ b/runtest/syscalls
>> @@ -684,6 +684,8 @@ kill11 kill11
>> kill12 kill12
>> kill13 kill13
>>
>> +landlock01 landlock01
>> +
>> lchown01 lchown01
>> lchown01_16 lchown01_16
>> lchown02 lchown02
>> diff --git a/testcases/kernel/syscalls/landlock/.gitignore
>> b/testcases/kernel/syscalls/landlock/.gitignore
>> new file mode 100644
>> index 000000000..b69f9b94a
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/landlock/.gitignore
>> @@ -0,0 +1 @@
>> +landlock01
>> diff --git a/testcases/kernel/syscalls/landlock/Makefile
>> b/testcases/kernel/syscalls/landlock/Makefile
>> new file mode 100644
>> index 000000000..8cf1b9024
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/landlock/Makefile
>> @@ -0,0 +1,7 @@
>> +# SPDX-License-Identifier: GPL-2.0-or-later
>> +# Copyright (C) 2024 SUSE LLC Andrea Cervesato <
>> andrea.cervesato@suse.com>
>> +
>> +top_srcdir ?= ../../../..
>> +
>> +include $(top_srcdir)/include/mk/testcases.mk
>> +include $(top_srcdir)/include/mk/generic_leaf_target.mk
>> diff --git a/testcases/kernel/syscalls/landlock/landlock01.c
>> b/testcases/kernel/syscalls/landlock/landlock01.c
>> new file mode 100644
>> index 000000000..90f338fb0
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/landlock/landlock01.c
>> @@ -0,0 +1,92 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright (C) 2024 SUSE LLC Andrea Cervesato <
>> andrea.cervesato@suse.com>
>> + */
>> +
>> +/*\
>> + * [Description]
>> + *
>> + * This test verifies that landlock_create_ruleset syscall fails with
>> the right
>> + * error codes:
>> + *
>> + * - EINVAL Unknown flags, or unknown access, or too small size
>> + * - E2BIG size is too big
>> + * - EFAULT attr was not a valid address
>> + * - ENOMSG Empty accesses (i.e., attr->handled_access_fs is 0)
>> + */
>> +
>> +#include "landlock_common.h"
>> +
>> +static struct landlock_ruleset_attr *ruleset_attr;
>> +static struct landlock_ruleset_attr *null_attr;
>> +static size_t rule_size;
>> +static size_t rule_small_size;
>> +static size_t rule_big_size;
>> +
>> +static struct tcase {
>> + struct landlock_ruleset_attr **attr;
>> + uint64_t access_fs;
>> + size_t *size;
>> + uint32_t flags;
>> + int exp_errno;
>> + char *msg;
>> +} tcases[] = {
>> + {&ruleset_attr, -1, &rule_size, 0, EINVAL, "Unknown access"},
>> + {&ruleset_attr, 0, &rule_small_size, 0, EINVAL, "Size is too
>> small"},
>> + {&ruleset_attr, 0, &rule_size, -1, EINVAL, "Unknown flags"},
>> + {&ruleset_attr, 0, &rule_big_size, 0, E2BIG, "Size is too big"},
>> + {&null_attr, 0, &rule_size, 0, EFAULT, "Invalid attr address"},
>> + {&ruleset_attr, 0, &rule_size, 0, ENOMSG, "Empty accesses"},
>> +};
>> +
>> +static void run(unsigned int n)
>> +{
>> + struct tcase *tc = &tcases[n];
>> +
>> + if (*tc->attr)
>> + (*tc->attr)->handled_access_fs = tc->access_fs;
>> +
>> + TST_EXP_FAIL(tst_syscall(__NR_landlock_create_ruleset,
>> + *tc->attr, *tc->size, tc->flags),
>> + tc->exp_errno,
>> + "%s",
>> + tc->msg);
>> +
>> + if (TST_RET >= 0)
>> + SAFE_CLOSE(TST_RET);
>> +}
>> +
>> +static void setup(void)
>> +{
>> + verify_landlock_is_enabled();
>> +
>> + rule_size = sizeof(struct landlock_ruleset_attr);
>> +
>> +#ifdef HAVE_STRUCT_LANDLOCK_RULESET_ATTR_HANDLED_ACCESS_NET
>> + rule_small_size = rule_size - sizeof(uint64_t);
>>
>
> This is incorrect, at least decrease 1 more number:
> rule_small_size = rule_size - sizeof(uint64_t) - 1;
>
> But, those are quite unnecessary to add the if macro conditions,
> as the kernel code explicitly compares the minimal struct with
> handled_access_fs via:
>
> offsetofend(typeof(ruleset_attr), handled_access_fs)
>
> I usually don't look at the kernel source code to write tests, because for
> us it should be a black box that could have wrong documentation.
> That's also the way we find bugs.
>
> I would go for still using the macros, but removing 1 more byte from the
> size when handled_access_net is defined.
>
Okay, fine.
We still have to adjust the case if someone introduces one more
new field similar to 'handled_access_net' to the structure in the future.
> (and Mickael said it should never change for backward compatibility reason)
>
> So it should be just simple like:
>
> --- a/testcases/kernel/syscalls/landlock/landlock01.c
> +++ b/testcases/kernel/syscalls/landlock/landlock01.c
> @@ -62,11 +62,15 @@ static void setup(void)
>
> rule_size = sizeof(struct landlock_ruleset_attr);
>
> -#ifdef HAVE_STRUCT_LANDLOCK_RULESET_ATTR_HANDLED_ACCESS_NET
> - rule_small_size = rule_size - sizeof(uint64_t);
> -#else
> - rule_small_size = rule_size - 1;
> -#endif
> + /*
> + * The new kernel introduces a new field 'handled_access_net' in
> the
> + * structure 'landlock_ruleset_attr'. However, in the function
> + * 'landlock_create_ruleset()', it still uses the first field
> + * 'handled_access_fs' to calculate the minimal size for backward
> + * compatibility reason. Therefore, here test 'sizeof(__u64) - 1'
> is
> + * sufficient to determine the minimum size for 'rule_small_size'.
> + */
> + rule_small_size = sizeof(__u64) - 1;
>
> rule_big_size = SAFE_SYSCONF(_SC_PAGESIZE) + 1;
> }
>
>
>
>> +#else
>> + rule_small_size = rule_size - 1;
>> +#endif
>> +
>> + rule_big_size = SAFE_SYSCONF(_SC_PAGESIZE) + 1;
>> +}
>> +
>> +static struct tst_test test = {
>> + .test = run,
>> + .tcnt = ARRAY_SIZE(tcases),
>> + .setup = setup,
>> + .min_kver = "5.13",
>> + .needs_root = 1,
>> + .needs_kconfigs = (const char *[]) {
>> + "CONFIG_SECURITY_LANDLOCK=y",
>> + NULL
>> + },
>> + .bufs = (struct tst_buffers []) {
>> + {&ruleset_attr, .size = sizeof(struct
>> landlock_ruleset_attr)},
>> + {},
>> + },
>> + .caps = (struct tst_cap []) {
>> + TST_CAP(TST_CAP_REQ, CAP_SYS_ADMIN),
>> + {}
>> + },
>> +};
>> diff --git a/testcases/kernel/syscalls/landlock/landlock_common.h
>> b/testcases/kernel/syscalls/landlock/landlock_common.h
>> new file mode 100644
>> index 000000000..66f8fd19a
>> --- /dev/null
>> +++ b/testcases/kernel/syscalls/landlock/landlock_common.h
>> @@ -0,0 +1,74 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +/*
>> + * Copyright (C) 2024 SUSE LLC Andrea Cervesato <
>> andrea.cervesato@suse.com>
>> + */
>> +
>> +#ifndef LANDLOCK_COMMON_H
>> +
>> +#include "tst_test.h"
>> +#include "lapi/prctl.h"
>> +#include "lapi/fcntl.h"
>> +#include "lapi/landlock.h"
>> +
>> +static inline void verify_landlock_is_enabled(void)
>> +{
>> + int abi;
>> +
>> + abi = tst_syscall(__NR_landlock_create_ruleset,
>> + NULL, 0, LANDLOCK_CREATE_RULESET_VERSION);
>> +
>> + if (abi < 0) {
>> + if (errno == EOPNOTSUPP) {
>> + tst_brk(TCONF, "Landlock is currently disabled. "
>> + "Please enable it either via CONFIG_LSM
>> or "
>> + "'lsm' kernel parameter.");
>> + }
>> +
>> + tst_brk(TBROK | TERRNO, "landlock_create_ruleset error");
>> + }
>> +
>> + tst_res(TINFO, "Landlock ABI v%d", abi);
>> +}
>> +
>> +static inline void apply_landlock_rule(
>> + struct landlock_path_beneath_attr *path_beneath_attr,
>> + const int ruleset_fd,
>> + const int access,
>> + const char *path)
>> +{
>> + path_beneath_attr->allowed_access = access;
>> + path_beneath_attr->parent_fd = SAFE_OPEN(path, O_PATH |
>> O_CLOEXEC);
>> +
>> + SAFE_LANDLOCK_ADD_RULE(
>> + ruleset_fd,
>> + LANDLOCK_RULE_PATH_BENEATH,
>> + path_beneath_attr,
>> + 0);
>> +
>> + SAFE_CLOSE(path_beneath_attr->parent_fd);
>> +}
>> +
>> +static inline void enforce_ruleset(const int ruleset_fd)
>> +{
>> + SAFE_PRCTL(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
>> + SAFE_LANDLOCK_RESTRICT_SELF(ruleset_fd, 0);
>> +}
>> +
>> +static inline void apply_landlock_layer(
>> + struct landlock_ruleset_attr *ruleset_attr,
>> + struct landlock_path_beneath_attr *path_beneath_attr,
>> + const char *path,
>> + const int access)
>> +{
>> + int ruleset_fd;
>> +
>> + ruleset_fd = SAFE_LANDLOCK_CREATE_RULESET(
>> + ruleset_attr, sizeof(struct landlock_ruleset_attr), 0);
>> +
>> + apply_landlock_rule(path_beneath_attr, ruleset_fd, access, path);
>> + enforce_ruleset(ruleset_fd);
>> +
>> + SAFE_CLOSE(ruleset_fd);
>> +}
>> +
>> +#endif
>>
>> --
>> 2.43.0
>>
>>
>
> --
> Regards,
> Li Wang
>
> Andrea
>
--
Regards,
Li Wang
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