在 2024/10/15 23:31, Shuah Khan 写道:
On 10/15/24 04:59, zhouyuhang wrote:
From: zhouyuhang zhouyuhang@kylinos.cn
The libcap commit aca076443591 ("Make cap_t operations thread safe.") added a __u8 mutex at the beginning of the struct _cap_struct, it changes the offset of the members in the structure that breaks the assumption made in the "struct libcap" definition in clone3_cap_checkpoint_restore.c. This will make the test fail. So use the capget and capset syscall directly and remove the libcap library dependency like the commit 663af70aabb7 ("bpf: selftests: Add helpers to directly use the capget and capset syscall") does.
Signed-off-by: zhouyuhang zhouyuhang@kylinos.cn
tools/testing/selftests/clone3/Makefile | 1 - .../clone3/clone3_cap_checkpoint_restore.c | 53 ++++++++----------- .../selftests/clone3/clone3_cap_helpers.h | 23 ++++++++ 3 files changed, 44 insertions(+), 33 deletions(-) create mode 100644 tools/testing/selftests/clone3/clone3_cap_helpers.h
diff --git a/tools/testing/selftests/clone3/Makefile b/tools/testing/selftests/clone3/Makefile index 84832c369a2e..59d26e8da8d2 100644 --- a/tools/testing/selftests/clone3/Makefile +++ b/tools/testing/selftests/clone3/Makefile @@ -1,6 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 CFLAGS += -g -std=gnu99 $(KHDR_INCLUDES) -LDLIBS += -lcap TEST_GEN_PROGS := clone3 clone3_clear_sighand clone3_set_tid \ clone3_cap_checkpoint_restore diff --git a/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c b/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c index 3c196fa86c99..242088eeec88 100644 --- a/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c +++ b/tools/testing/selftests/clone3/clone3_cap_checkpoint_restore.c @@ -15,7 +15,6 @@ #include <stdio.h> #include <stdlib.h> #include <stdbool.h> -#include <sys/capability.h> #include <sys/prctl.h> #include <sys/syscall.h> #include <sys/types.h> @@ -26,6 +25,7 @@ #include "../kselftest_harness.h" #include "clone3_selftests.h" +#include "clone3_cap_helpers.h" static void child_exit(int ret) { @@ -87,47 +87,36 @@ static int test_clone3_set_tid(struct __test_metadata *_metadata, return ret; } -struct libcap { - struct __user_cap_header_struct hdr; - struct __user_cap_data_struct data[2]; -};
static int set_capability(void) { - cap_value_t cap_values[] = { CAP_SETUID, CAP_SETGID }; - struct libcap *cap; - int ret = -1; - cap_t caps;
- caps = cap_get_proc(); - if (!caps) { - perror("cap_get_proc"); + struct __user_cap_data_struct data[2]; + struct __user_cap_header_struct hdr = { + .version = _LINUX_CAPABILITY_VERSION_3, + }; + __u32 cap0 = 1 << CAP_SETUID | 1 << CAP_SETGID; + __u32 cap1 = 1 << (CAP_CHECKPOINT_RESTORE - 32); + int ret;
+ ret = capget(&hdr, data); + if (ret) { + perror("capget"); return -1; } /* Drop all capabilities */ - if (cap_clear(caps)) { - perror("cap_clear"); - goto out; - } + memset(&data, 0, sizeof(data)); - cap_set_flag(caps, CAP_EFFECTIVE, 2, cap_values, CAP_SET); - cap_set_flag(caps, CAP_PERMITTED, 2, cap_values, CAP_SET); + data[0].effective |= cap0; + data[0].permitted |= cap0; - cap = (struct libcap *) caps; + data[1].effective |= cap1; + data[1].permitted |= cap1; - /* 40 -> CAP_CHECKPOINT_RESTORE */ - cap->data[1].effective |= 1 << (40 - 32); - cap->data[1].permitted |= 1 << (40 - 32);
- if (cap_set_proc(caps)) { - perror("cap_set_proc"); - goto out; + ret = capset(&hdr, data); + if (ret) { + perror("capset"); + return -1; } - ret = 0; -out: - if (cap_free(caps)) - perror("cap_free"); return ret; } diff --git a/tools/testing/selftests/clone3/clone3_cap_helpers.h b/tools/testing/selftests/clone3/clone3_cap_helpers.h new file mode 100644 index 000000000000..3fa59ef68fb8 --- /dev/null +++ b/tools/testing/selftests/clone3/clone3_cap_helpers.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __CLONE3_CAP_HELPERS_H +#define __CLONE3_CAP_HELPERS_H
+#include <linux/capability.h>
+/*
- Compatible with older version
- header file without defined
- CAP_CHECKPOINT_RESTORE.
- */
+#ifndef CAP_CHECKPOINT_RESTORE +#define CAP_CHECKPOINT_RESTORE 40 +#endif
+/*
- Removed the libcap library dependency.
- So declare them here directly.
- */
+int capget(cap_user_header_t header, cap_user_data_t data); +int capset(cap_user_header_t header, const cap_user_data_t data);
Sorry you haven't addressed my comments on your v1 yet.
I repeat that this is not the right direction to define system calls locally.
I got it. I am willing to modify the code so that syscalls are not defined in local files, but this would require including sys/capability.h which would not remove the dependency on the libcap library. So, should we directly use syscalls or use the libcap library function in the "set_capability" function, or do you have a better way. I'd like to refer to your advice.
Try this:
Run make headers in the kernel repo. Build without making any changes. Then add you changes and add linux/capability.h to include files
Tell me what happens.
thanks, -- Shuah
I tried this, here are my steps.
Firstly, I ran 'make headers' in the kernel repo and it was successful. Then I wasn't quite sure which path you were referring to as' build ', so I compiled and installed libcap, and also compiled test, all of which were successful. Afterwards, I applied my patch and the test was successfully built and running. I guess what you're trying to express may be that these system calls have already been defined in sys/capability, and those defined in the local file are duplicated with it. So I included sys/capability.h and linux/capability.h and defined the system calls in the test, but there were no errors.
I think there may be a problem with my operation, and I hope you can point it out.