Small optimization to avoid coredump writing during the stack protector tests. Adds prctl() as prerequisite. This series is based on nolibc/20230524-nolibc-rv32+stkp4 Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- Thomas Weißschuh (2): tools/nolibc: add support for prctl() selftests/nolibc: prevent coredumps during test execution tools/include/nolibc/sys.h | 27 +++++++++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 3 +++ 2 files changed, 30 insertions(+) --- base-commit: 1974a2b5fd434812b32952b09df7b79fdee8104d change-id: 20230526-nolibc-test-no-dump-a1b1d9557df8 Best regards, -- Thomas Weißschuh <linux@weissschuh.net> It will be used to disable core dumps from the child spawned to validate the stack protector functionality. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- tools/include/nolibc/sys.h | 27 +++++++++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 2 ++ 2 files changed, 29 insertions(+) diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index XXXXXXX..XXXXXXX 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -XXX,XX +XXX,XX @@ #include <linux/fcntl.h> /* for O_* and AT_* */ #include <linux/stat.h> /* for statx() */ #include <linux/reboot.h> /* for LINUX_REBOOT_* */ +#include <linux/prctl.h> #include "arch.h" #include "errno.h" @@ -XXX,XX +XXX,XX @@ int open(const char *path, int flags, ...) } +/* + * int prctl(int option, unsigned long arg2, unsigned long arg3, + * unsigned long arg4, unsigned long arg5); + */ + +static __attribute__((unused)) +int sys_prctl(int option, unsigned long arg2, unsigned long arg3, + unsigned long arg4, unsigned long arg5) +{ + return my_syscall5(__NR_prctl, option, arg2, arg3, arg4, arg5); +} + +static __attribute__((unused)) +int prctl(int option, unsigned long arg2, unsigned long arg3, + unsigned long arg4, unsigned long arg5) +{ + int ret = sys_prctl(option, arg2, arg3, arg4, arg5); + + if (ret < 0) { + SET_ERRNO(-ret); + ret = -1; + } + return ret; +} + + /* * int pivot_root(const char *new, const char *old); */ diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index XXXXXXX..XXXXXXX 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -XXX,XX +XXX,XX @@ #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/mount.h> +#include <sys/prctl.h> #include <sys/reboot.h> #include <sys/stat.h> #include <sys/syscall.h> @@ -XXX,XX +XXX,XX @@ int run_syscall(int min, int max) CASE_TEST(poll_null); EXPECT_SYSZR(1, poll(NULL, 0, 0)); break; CASE_TEST(poll_stdout); EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break; CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break; + CASE_TEST(prctl); EXPECT_SYSER(1, prctl(PR_SET_NAME, NULL, 0, 0, 0), -1, EFAULT); break; CASE_TEST(read_badf); EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break; CASE_TEST(sched_yield); EXPECT_SYSZR(1, sched_yield()); break; CASE_TEST(select_null); EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break; -- 2.40.1 The child process forked during stackprotector tests intentionally gets killed with SIGABRT. By default this will trigger writing a coredump. The writing of the coredump can spam the systems coredump machinery and take some time. Timings for the full run of nolibc-test: Before: 200ms After: 20ms This is on a desktop x86 system with systemd-coredumpd enabled. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- tools/testing/selftests/nolibc/nolibc-test.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index XXXXXXX..XXXXXXX 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -XXX,XX +XXX,XX @@ static int run_protection(int min, int max) close(STDOUT_FILENO); close(STDERR_FILENO); + prctl(PR_SET_DUMPABLE, 0, 0, 0, 0); smash_stack(); return 1; -- 2.40.1 Small optimization to avoid coredump writing during the stack protector tests. Adds prctl() as prerequisite. This series is based on nolibc/20230524-nolibc-rv32+stkp4 Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- Changes in v2: - Fix compilation warning in prctl() testcase - Link to v1: https://lore.kernel.org/r/20230526-nolibc-test-no-dump-v1-0-62e724a96db2@weissschuh.net --- Thomas Weißschuh (2): tools/nolibc: add support for prctl() selftests/nolibc: prevent coredumps during test execution tools/include/nolibc/sys.h | 27 +++++++++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 3 +++ 2 files changed, 30 insertions(+) --- base-commit: 1974a2b5fd434812b32952b09df7b79fdee8104d change-id: 20230526-nolibc-test-no-dump-a1b1d9557df8 Best regards, -- Thomas Weißschuh <linux@weissschuh.net> It will be used to disable core dumps from the child spawned to validate the stack protector functionality. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- tools/include/nolibc/sys.h | 27 +++++++++++++++++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 2 ++ 2 files changed, 29 insertions(+) diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index XXXXXXX..XXXXXXX 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -XXX,XX +XXX,XX @@ #include <linux/fcntl.h> /* for O_* and AT_* */ #include <linux/stat.h> /* for statx() */ #include <linux/reboot.h> /* for LINUX_REBOOT_* */ +#include <linux/prctl.h> #include "arch.h" #include "errno.h" @@ -XXX,XX +XXX,XX @@ int open(const char *path, int flags, ...) } +/* + * int prctl(int option, unsigned long arg2, unsigned long arg3, + * unsigned long arg4, unsigned long arg5); + */ + +static __attribute__((unused)) +int sys_prctl(int option, unsigned long arg2, unsigned long arg3, + unsigned long arg4, unsigned long arg5) +{ + return my_syscall5(__NR_prctl, option, arg2, arg3, arg4, arg5); +} + +static __attribute__((unused)) +int prctl(int option, unsigned long arg2, unsigned long arg3, + unsigned long arg4, unsigned long arg5) +{ + int ret = sys_prctl(option, arg2, arg3, arg4, arg5); + + if (ret < 0) { + SET_ERRNO(-ret); + ret = -1; + } + return ret; +} + + /* * int pivot_root(const char *new, const char *old); */ diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index XXXXXXX..XXXXXXX 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -XXX,XX +XXX,XX @@ #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/mount.h> +#include <sys/prctl.h> #include <sys/reboot.h> #include <sys/stat.h> #include <sys/syscall.h> @@ -XXX,XX +XXX,XX @@ int run_syscall(int min, int max) CASE_TEST(poll_null); EXPECT_SYSZR(1, poll(NULL, 0, 0)); break; CASE_TEST(poll_stdout); EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break; CASE_TEST(poll_fault); EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break; + CASE_TEST(prctl); EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break; CASE_TEST(read_badf); EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break; CASE_TEST(sched_yield); EXPECT_SYSZR(1, sched_yield()); break; CASE_TEST(select_null); EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break; -- 2.40.1 The child process forked during stackprotector tests intentionally gets killed with SIGABRT. By default this will trigger writing a coredump. The writing of the coredump can spam the systems coredump machinery and take some time. Timings for the full run of nolibc-test: Before: 200ms After: 20ms This is on a desktop x86 system with systemd-coredumpd enabled. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- tools/testing/selftests/nolibc/nolibc-test.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index XXXXXXX..XXXXXXX 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -XXX,XX +XXX,XX @@ static int run_protection(int min, int max) close(STDOUT_FILENO); close(STDERR_FILENO); + prctl(PR_SET_DUMPABLE, 0, 0, 0, 0); smash_stack(); return 1; -- 2.40.1