From 223e660bc7638d126a0e4fbace4f33f2895788c4 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 20 Sep 2019 10:30:06 +0200 Subject: seccomp: avoid overflow in implicit constant conversion MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit USER_NOTIF_MAGIC is assigned to int variables in this test so set it to INT_MAX to avoid warnings: seccomp_bpf.c: In function ‘user_notification_continue’: seccomp_bpf.c:3088:26: warning: overflow in implicit constant conversion [-Woverflow] #define USER_NOTIF_MAGIC 116983961184613L ^ seccomp_bpf.c:3572:15: note: in expansion of macro ‘USER_NOTIF_MAGIC’ resp.error = USER_NOTIF_MAGIC; ^~~~~~~~~~~~~~~~ Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace") Signed-off-by: Christian Brauner Reviewed-by: Tyler Hicks Cc: Andy Lutomirski Cc: Will Drewry Cc: Shuah Khan Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: Tycho Andersen Cc: stable@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: netdev@vger.kernel.org Cc: bpf@vger.kernel.org Reviewed-by: Tycho Andersen Link: https://lore.kernel.org/r/20190920083007.11475-3-christian.brauner@ubuntu.com Signed-off-by: Kees Cook --- tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 7f8b5c8982e3..b505bb062d07 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -3077,7 +3078,7 @@ static int user_trap_syscall(int nr, unsigned int flags) return seccomp(SECCOMP_SET_MODE_FILTER, flags, &prog); } -#define USER_NOTIF_MAGIC 116983961184613L +#define USER_NOTIF_MAGIC INT_MAX TEST(user_notification_basic) { pid_t pid; -- cgit v1.2.3 From 0eebfed2954f152259cae0ad57b91d3ea92968e8 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 20 Sep 2019 10:30:07 +0200 Subject: seccomp: test SECCOMP_USER_NOTIF_FLAG_CONTINUE Test whether a syscall can be performed after having been intercepted by the seccomp notifier. The test uses dup() and kcmp() since it allows us to nicely test whether the dup() syscall actually succeeded by comparing whether the fds refer to the same underlying struct file. Signed-off-by: Christian Brauner Cc: Andy Lutomirski Cc: Will Drewry Cc: Shuah Khan Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: Tycho Andersen CC: Tyler Hicks Cc: stable@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: netdev@vger.kernel.org Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20190920083007.11475-4-christian.brauner@ubuntu.com Signed-off-by: Kees Cook --- tools/testing/selftests/seccomp/seccomp_bpf.c | 107 ++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) (limited to 'tools/testing') diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index b505bb062d07..47d65d9b77f6 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -44,6 +44,7 @@ #include #include #include +#include #include #include @@ -167,6 +168,10 @@ struct seccomp_metadata { #define SECCOMP_RET_USER_NOTIF 0x7fc00000U +#ifndef SECCOMP_USER_NOTIF_FLAG_CONTINUE +#define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001 +#endif + #define SECCOMP_IOC_MAGIC '!' #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) @@ -3486,6 +3491,108 @@ TEST(seccomp_get_notif_sizes) EXPECT_EQ(sizes.seccomp_notif_resp, sizeof(struct seccomp_notif_resp)); } +static int filecmp(pid_t pid1, pid_t pid2, int fd1, int fd2) +{ +#ifdef __NR_kcmp + return syscall(__NR_kcmp, pid1, pid2, KCMP_FILE, fd1, fd2); +#else + errno = ENOSYS; + return -1; +#endif +} + +TEST(user_notification_continue) +{ + pid_t pid; + long ret; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + struct pollfd pollfd; + + ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + listener = user_trap_syscall(__NR_dup, SECCOMP_FILTER_FLAG_NEW_LISTENER); + ASSERT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + int dup_fd, pipe_fds[2]; + pid_t self; + + ret = pipe(pipe_fds); + if (ret < 0) + exit(1); + + dup_fd = dup(pipe_fds[0]); + if (dup_fd < 0) + exit(1); + + self = getpid(); + + ret = filecmp(self, self, pipe_fds[0], dup_fd); + if (ret) + exit(2); + + exit(0); + } + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLIN); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLOUT); + + EXPECT_EQ(req.data.nr, __NR_dup); + + resp.id = req.id; + resp.flags = SECCOMP_USER_NOTIF_FLAG_CONTINUE; + + /* + * Verify that setting SECCOMP_USER_NOTIF_FLAG_CONTINUE enforces other + * args be set to 0. + */ + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, EINVAL); + + resp.error = USER_NOTIF_MAGIC; + resp.val = 0; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, EINVAL); + + resp.error = 0; + resp.val = 0; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0) { + if (errno == EINVAL) + XFAIL(goto skip, "Kernel does not support SECCOMP_USER_NOTIF_FLAG_CONTINUE"); + } + +skip: + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)) { + if (WEXITSTATUS(status) == 2) { + XFAIL(return, "Kernel does not support kcmp() syscall"); + return; + } + } +} + /* * TODO: * - add microbenchmarks -- cgit v1.2.3 From 2aa8d8d04ca29c3269154e1d48855e498be8882f Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Mon, 21 Oct 2019 11:10:55 +0200 Subject: seccomp: fix SECCOMP_USER_NOTIF_FLAG_CONTINUE test MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The ifndef for SECCOMP_USER_NOTIF_FLAG_CONTINUE was placed under the ifndef for the SECCOMP_FILTER_FLAG_NEW_LISTENER feature. This will not work on systems that do support SECCOMP_FILTER_FLAG_NEW_LISTENER but do not support SECCOMP_USER_NOTIF_FLAG_CONTINUE. So move the latter ifndef out of the former ifndef's scope. 2019-10-20 11:14:01 make run_tests -C seccomp make: Entering directory '/usr/src/perf_selftests-x86_64-rhel-7.6-0eebfed2954f152259cae0ad57b91d3ea92968e8/tools/testing/selftests/seccomp' gcc -Wl,-no-as-needed -Wall seccomp_bpf.c -lpthread -o seccomp_bpf seccomp_bpf.c: In function ‘user_notification_continue’: seccomp_bpf.c:3562:15: error: ‘SECCOMP_USER_NOTIF_FLAG_CONTINUE’ undeclared (first use in this function) resp.flags = SECCOMP_USER_NOTIF_FLAG_CONTINUE; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ seccomp_bpf.c:3562:15: note: each undeclared identifier is reported only once for each function it appears in Makefile:12: recipe for target 'seccomp_bpf' failed make: *** [seccomp_bpf] Error 1 make: Leaving directory '/usr/src/perf_selftests-x86_64-rhel-7.6-0eebfed2954f152259cae0ad57b91d3ea92968e8/tools/testing/selftests/seccomp' Reported-by: kernel test robot Fixes: 0eebfed2954f ("seccomp: test SECCOMP_USER_NOTIF_FLAG_CONTINUE") Cc: linux-kselftest@vger.kernel.org Signed-off-by: Christian Brauner Reviewed-by: Tycho Andersen Link: https://lore.kernel.org/r/20191021091055.4644-1-christian.brauner@ubuntu.com Signed-off-by: Kees Cook --- tools/testing/selftests/seccomp/seccomp_bpf.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 47d65d9b77f6..c1f6d9b3c954 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -168,10 +168,6 @@ struct seccomp_metadata { #define SECCOMP_RET_USER_NOTIF 0x7fc00000U -#ifndef SECCOMP_USER_NOTIF_FLAG_CONTINUE -#define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001 -#endif - #define SECCOMP_IOC_MAGIC '!' #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) @@ -210,6 +206,10 @@ struct seccomp_notif_sizes { #define PTRACE_EVENTMSG_SYSCALL_EXIT 2 #endif +#ifndef SECCOMP_USER_NOTIF_FLAG_CONTINUE +#define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001 +#endif + #ifndef seccomp int seccomp(unsigned int op, unsigned int flags, void *args) { -- cgit v1.2.3