* [PATCH bpf-next v4 1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test
2024-07-31 6:37 [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
@ 2024-07-31 6:37 ` Alexis Lothoré (eBPF Foundation)
2024-07-31 6:37 ` [PATCH bpf-next v4 2/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Alexis Lothoré (eBPF Foundation) @ 2024-07-31 6:37 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Eduard Zingerman, Song Liu, Yonghong Song,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Mykola Lysenko, Shuah Khan
Cc: ebpf, Thomas Petazzoni, Alan Maguire, Martin KaFai Lau, bpf,
linux-kselftest, linux-kernel,
Alexis Lothoré (eBPF Foundation)
test_dev_cgroup currently loads a small bpf program allowing any access on
urandom and zero devices, disabling access to any other device. It makes
migrating this test to test_progs impossible, since this one manipulates
extensively /dev/null.
Allow /dev/null manipulation in dev_cgroup program to make its usage in
test_progs framework possible. Update test_dev_cgroup.c as well to match
this change while it has not been removed.
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
tools/testing/selftests/bpf/progs/dev_cgroup.c | 4 ++--
tools/testing/selftests/bpf/test_dev_cgroup.c | 18 +++++++++---------
2 files changed, 11 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/dev_cgroup.c b/tools/testing/selftests/bpf/progs/dev_cgroup.c
index 79b54a4fa244..c1dfbd2b56fc 100644
--- a/tools/testing/selftests/bpf/progs/dev_cgroup.c
+++ b/tools/testing/selftests/bpf/progs/dev_cgroup.c
@@ -41,14 +41,14 @@ int bpf_prog1(struct bpf_cgroup_dev_ctx *ctx)
bpf_trace_printk(fmt, sizeof(fmt), ctx->major, ctx->minor);
#endif
- /* Allow access to /dev/zero and /dev/random.
+ /* Allow access to /dev/null and /dev/urandom.
* Forbid everything else.
*/
if (ctx->major != 1 || type != BPF_DEVCG_DEV_CHAR)
return 0;
switch (ctx->minor) {
- case 5: /* 1:5 /dev/zero */
+ case 3: /* 1:3 /dev/null */
case 9: /* 1:9 /dev/urandom */
return 1;
}
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
index adeaf63cb6fa..33f544f0005a 100644
--- a/tools/testing/selftests/bpf/test_dev_cgroup.c
+++ b/tools/testing/selftests/bpf/test_dev_cgroup.c
@@ -54,25 +54,25 @@ int main(int argc, char **argv)
goto err;
}
- /* All operations with /dev/zero and and /dev/urandom are allowed,
+ /* All operations with /dev/null and /dev/urandom are allowed,
* everything else is forbidden.
*/
- assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
- assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
- assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-
- /* /dev/zero is whitelisted */
assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
- assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
+ assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5"));
assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
- assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
+ /* /dev/null is whitelisted */
+ assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+ assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0);
+ assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+
+ assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
/* src is allowed, target is forbidden */
assert(system("dd if=/dev/urandom of=/dev/full count=64"));
/* src is forbidden, target is allowed */
- assert(system("dd if=/dev/random of=/dev/zero count=64"));
+ assert(system("dd if=/dev/random of=/dev/null count=64"));
error = 0;
printf("test_dev_cgroup:PASS\n");
--
2.45.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH bpf-next v4 2/3] selftests/bpf: convert test_dev_cgroup to test_progs
2024-07-31 6:37 [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
2024-07-31 6:37 ` [PATCH bpf-next v4 1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test Alexis Lothoré (eBPF Foundation)
@ 2024-07-31 6:37 ` Alexis Lothoré (eBPF Foundation)
2024-07-31 6:37 ` [PATCH bpf-next v4 3/3] selftests/bpf: add wrong type test to cgroup dev Alexis Lothoré (eBPF Foundation)
2024-07-31 18:40 ` [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: Alexis Lothoré (eBPF Foundation) @ 2024-07-31 6:37 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Eduard Zingerman, Song Liu, Yonghong Song,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Mykola Lysenko, Shuah Khan
Cc: ebpf, Thomas Petazzoni, Alan Maguire, Martin KaFai Lau, bpf,
linux-kselftest, linux-kernel,
Alexis Lothoré (eBPF Foundation)
test_dev_cgroup is defined as a standalone test program, and so is not
executed in CI.
Convert it to test_progs framework so it is tested automatically in CI, and
remove the old test. In order to be able to run it in test_progs, /dev/null
must remain usable, so change the new test to test operations on devices
1:3 as valid, and operations on devices 1:5 (/dev/zero) as invalid.
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v4:
- split ret and errno testing
Changes in v3:
- delete mknod file only when is has been created
- use bpf_program__attach_cgroup instead of bpf_prog_attach
- reorder subtests
- collect review/ack tags
Changes in v2:
- pass expected return code to subtest function instead of boolean pass/not
pass
- also pass buffer and buffer size for read/write subtests
- fix faulty fd check on read/write tests expected to fail
---
tools/testing/selftests/bpf/.gitignore | 1 -
tools/testing/selftests/bpf/Makefile | 2 -
.../testing/selftests/bpf/prog_tests/cgroup_dev.c | 121 +++++++++++++++++++++
tools/testing/selftests/bpf/test_dev_cgroup.c | 85 ---------------
4 files changed, 121 insertions(+), 88 deletions(-)
diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 4e4aae8aa7ec..8f14d8faeb0b 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -9,7 +9,6 @@ test_lpm_map
test_tag
FEATURE-DUMP.libbpf
fixdep
-test_dev_cgroup
/test_progs
/test_progs-no_alu32
/test_progs-bpf_gcc
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 564e1fdf80b6..bb02a3540d7a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -69,7 +69,6 @@ endif
# Order correspond to 'make run_tests' order
TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
- test_dev_cgroup \
test_sock test_sockmap get_cgroup_id_user \
test_cgroup_storage \
test_tcpnotify_user test_sysctl \
@@ -294,7 +293,6 @@ JSON_WRITER := $(OUTPUT)/json_writer.o
CAP_HELPERS := $(OUTPUT)/cap_helpers.o
NETWORK_HELPERS := $(OUTPUT)/network_helpers.o
-$(OUTPUT)/test_dev_cgroup: $(CGROUP_HELPERS) $(TESTING_HELPERS)
$(OUTPUT)/test_skb_cgroup_id_user: $(CGROUP_HELPERS) $(TESTING_HELPERS)
$(OUTPUT)/test_sock: $(CGROUP_HELPERS) $(TESTING_HELPERS)
$(OUTPUT)/test_sockmap: $(CGROUP_HELPERS) $(TESTING_HELPERS)
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
new file mode 100644
index 000000000000..8661e145ba84
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <errno.h>
+#include "test_progs.h"
+#include "cgroup_helpers.h"
+#include "dev_cgroup.skel.h"
+
+#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
+#define TEST_BUFFER_SIZE 64
+
+static void test_mknod(const char *path, mode_t mode, int dev_major,
+ int dev_minor, int expected_ret, int expected_errno)
+{
+ int ret;
+
+ unlink(path);
+ ret = mknod(path, mode, makedev(dev_major, dev_minor));
+ ASSERT_EQ(ret, expected_ret, "mknod");
+ if (expected_ret)
+ ASSERT_EQ(errno, expected_errno, "mknod errno");
+ else
+ unlink(path);
+}
+
+static void test_read(const char *path, char *buf, int buf_size,
+ int expected_ret, int expected_errno)
+{
+ int ret, fd;
+
+ fd = open(path, O_RDONLY);
+
+ /* A bare open on unauthorized device should fail */
+ if (expected_ret < 0) {
+ ASSERT_EQ(fd, expected_ret, "open ret for read");
+ ASSERT_EQ(errno, expected_errno, "open errno for read");
+ if (fd >= 0)
+ close(fd);
+ return;
+ }
+
+ if (!ASSERT_OK_FD(fd, "open ret for read"))
+ return;
+
+ ret = read(fd, buf, buf_size);
+ ASSERT_EQ(ret, expected_ret, "read");
+
+ close(fd);
+}
+
+static void test_write(const char *path, char *buf, int buf_size,
+ int expected_ret, int expected_errno)
+{
+ int ret, fd;
+
+ fd = open(path, O_WRONLY);
+
+ /* A bare open on unauthorized device should fail */
+ if (expected_ret < 0) {
+ ASSERT_EQ(fd, expected_ret, "open ret for write");
+ ASSERT_EQ(errno, expected_errno, "open errno for write");
+ if (fd >= 0)
+ close(fd);
+ return;
+ }
+
+ if (!ASSERT_OK_FD(fd, "open ret for write"))
+ return;
+
+ ret = write(fd, buf, buf_size);
+ ASSERT_EQ(ret, expected_ret, "write");
+
+ close(fd);
+}
+
+void test_cgroup_dev(void)
+{
+ char buf[TEST_BUFFER_SIZE] = "some random test data";
+ struct dev_cgroup *skel;
+ int cgroup_fd;
+
+ cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+ if (!ASSERT_OK_FD(cgroup_fd, "cgroup switch"))
+ return;
+
+ skel = dev_cgroup__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "load program"))
+ goto cleanup_cgroup;
+
+ skel->links.bpf_prog1 =
+ bpf_program__attach_cgroup(skel->progs.bpf_prog1, cgroup_fd);
+ if (!ASSERT_OK_PTR(skel->links.bpf_prog1, "attach_program"))
+ goto cleanup_progs;
+
+ if (test__start_subtest("allow-mknod"))
+ test_mknod("/dev/test_dev_cgroup_null", S_IFCHR, 1, 3, 0, 0);
+
+ if (test__start_subtest("allow-read"))
+ test_read("/dev/urandom", buf, TEST_BUFFER_SIZE,
+ TEST_BUFFER_SIZE, 0);
+
+ if (test__start_subtest("allow-write"))
+ test_write("/dev/null", buf, TEST_BUFFER_SIZE,
+ TEST_BUFFER_SIZE, 0);
+
+ if (test__start_subtest("deny-mknod"))
+ test_mknod("/dev/test_dev_cgroup_zero", S_IFCHR, 1, 5, -1,
+ EPERM);
+
+ if (test__start_subtest("deny-read"))
+ test_read("/dev/random", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+ if (test__start_subtest("deny-write"))
+ test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+cleanup_progs:
+ dev_cgroup__destroy(skel);
+cleanup_cgroup:
+ cleanup_cgroup_environment();
+}
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
deleted file mode 100644
index 33f544f0005a..000000000000
--- a/tools/testing/selftests/bpf/test_dev_cgroup.c
+++ /dev/null
@@ -1,85 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2017 Facebook
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <assert.h>
-#include <sys/time.h>
-
-#include <linux/bpf.h>
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "cgroup_helpers.h"
-#include "testing_helpers.h"
-
-#define DEV_CGROUP_PROG "./dev_cgroup.bpf.o"
-
-#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
-
-int main(int argc, char **argv)
-{
- struct bpf_object *obj;
- int error = EXIT_FAILURE;
- int prog_fd, cgroup_fd;
- __u32 prog_cnt;
-
- /* Use libbpf 1.0 API mode */
- libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
- if (bpf_prog_test_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
- &obj, &prog_fd)) {
- printf("Failed to load DEV_CGROUP program\n");
- goto out;
- }
-
- cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
- if (cgroup_fd < 0) {
- printf("Failed to create test cgroup\n");
- goto out;
- }
-
- /* Attach bpf program */
- if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
- printf("Failed to attach DEV_CGROUP program");
- goto err;
- }
-
- if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
- &prog_cnt)) {
- printf("Failed to query attached programs");
- goto err;
- }
-
- /* All operations with /dev/null and /dev/urandom are allowed,
- * everything else is forbidden.
- */
- assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
- assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5"));
- assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-
- /* /dev/null is whitelisted */
- assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
- assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0);
- assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-
- assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
-
- /* src is allowed, target is forbidden */
- assert(system("dd if=/dev/urandom of=/dev/full count=64"));
-
- /* src is forbidden, target is allowed */
- assert(system("dd if=/dev/random of=/dev/null count=64"));
-
- error = 0;
- printf("test_dev_cgroup:PASS\n");
-
-err:
- cleanup_cgroup_environment();
-
-out:
- return error;
-}
--
2.45.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH bpf-next v4 3/3] selftests/bpf: add wrong type test to cgroup dev
2024-07-31 6:37 [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
2024-07-31 6:37 ` [PATCH bpf-next v4 1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test Alexis Lothoré (eBPF Foundation)
2024-07-31 6:37 ` [PATCH bpf-next v4 2/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
@ 2024-07-31 6:37 ` Alexis Lothoré (eBPF Foundation)
2024-07-31 18:40 ` [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: Alexis Lothoré (eBPF Foundation) @ 2024-07-31 6:37 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Eduard Zingerman, Song Liu, Yonghong Song,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Mykola Lysenko, Shuah Khan
Cc: ebpf, Thomas Petazzoni, Alan Maguire, Martin KaFai Lau, bpf,
linux-kselftest, linux-kernel,
Alexis Lothoré (eBPF Foundation)
Current cgroup_dev test mostly tests that device operation is accepted or
refused base on passed major/minor (and so, any operation performed during
test involves only char device)
Add a small subtest ensuring that the device type passed to bpf program
allows it to take decisions as well.
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v4:
- update parameters to test both ret and errno
Changes in v3:
- reorganize subtests order
Changes in v2:
- change test name ("null" block device does not make sense)
- use updated subtest API for this new subtest
---
tools/testing/selftests/bpf/prog_tests/cgroup_dev.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
index 8661e145ba84..5ab7547e38c0 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
@@ -114,6 +114,10 @@ void test_cgroup_dev(void)
if (test__start_subtest("deny-write"))
test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
+ if (test__start_subtest("deny-mknod-wrong-type"))
+ test_mknod("/dev/test_dev_cgroup_block", S_IFBLK, 1, 3, -1,
+ EPERM);
+
cleanup_progs:
dev_cgroup__destroy(skel);
cleanup_cgroup:
--
2.45.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs
2024-07-31 6:37 [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs Alexis Lothoré (eBPF Foundation)
` (2 preceding siblings ...)
2024-07-31 6:37 ` [PATCH bpf-next v4 3/3] selftests/bpf: add wrong type test to cgroup dev Alexis Lothoré (eBPF Foundation)
@ 2024-07-31 18:40 ` patchwork-bot+netdevbpf
2024-07-31 19:27 ` Alexis Lothoré
3 siblings, 1 reply; 6+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-07-31 18:40 UTC (permalink / raw)
To: =?utf-8?q?Alexis_Lothor=C3=A9_=28eBPF_Foundation=29_=3Calexis=2Elothore=40bo?=,
=?utf-8?q?otlin=2Ecom=3E?=
Cc: ast, daniel, andrii, martin.lau, eddyz87, song, yonghong.song,
john.fastabend, kpsingh, sdf, haoluo, jolsa, mykolal, shuah, ebpf,
thomas.petazzoni, alan.maguire, bpf, linux-kselftest,
linux-kernel
Hello:
This series was applied to bpf/bpf-next.git (master)
by Martin KaFai Lau <martin.lau@kernel.org>:
On Wed, 31 Jul 2024 08:37:24 +0200 you wrote:
> Hello,
> this small series aims to integrate test_dev_cgroup in test_progs so it
> could be run automatically in CI. The new version brings a few differences
> with the current one:
> - test now uses directly syscalls instead of wrapping commandline tools
> into system() calls
> - test_progs manipulates /dev/null (eg: redirecting test logs into it), so
> disabling access to it in the bpf program confuses the tests. To fix this,
> the first commit modifies the bpf program to allow access to char devices
> 1:3 (/dev/null), and disable access to char devices 1:5 (/dev/zero)
> - once test is converted, add a small subtest to also check for device type
> interpretation (char or block)
> - paths used in mknod tests are now in /dev instead of /tmp: due to the CI
> runner organisation and mountpoints manipulations, trying to create nodes
> in /tmp leads to errors unrelated to the test (ie, mknod calls refused by
> kernel, not the bpf program). I don't understand exactly the root cause
> at the deepest point (all I see in CI is an -ENXIO error on mknod when trying to
> create the node in tmp, and I can not make sense out of it neither
> replicate it locally), so I would gladly take inputs from anyone more
> educated than me about this.
>
> [...]
Here is the summary with links:
- [bpf-next,v4,1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test
https://git.kernel.org/bpf/bpf-next/c/ba6a9018502e
- [bpf-next,v4,2/3] selftests/bpf: convert test_dev_cgroup to test_progs
https://git.kernel.org/bpf/bpf-next/c/d83d8230e415
- [bpf-next,v4,3/3] selftests/bpf: add wrong type test to cgroup dev
https://git.kernel.org/bpf/bpf-next/c/84cdbff4a935
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 6+ messages in thread