selftests/seccomp: Be more precise with syscall arguments.

Certain syscall emulation layers strictly check that the number of
arguments match what the syscall handler expects. The KILL_one_arg_one and
KILL_one_arg_six tests passed more parameters than expected to various
syscalls, causing failures in this emulation mode. Instead, test using
syscalls that take the appropriate number of arguments.

Signed-off-by: Robert Sesek <rsesek@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

1 files changed, 35 insertions, 11 deletions

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index e7bc5d3533da..e38cc54942db 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -29,6 +29,9 @@
 #include <linux/elf.h>
 #include <sys/uio.h>
 #include <sys/utsname.h>
+#include <sys/fcntl.h>
+#include <sys/mman.h>
+#include <sys/times.h>
 
 #define _GNU_SOURCE
 #include <unistd.h>
@@ -429,14 +432,16 @@ TEST_SIGNAL(KILL_one, SIGSYS)
 
 TEST_SIGNAL(KILL_one_arg_one, SIGSYS)
 {
+        void *fatal_address;
         struct sock_filter filter[] = {
                 BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
                         offsetof(struct seccomp_data, nr)),
-                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
+                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_times, 1, 0),
                 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
                 /* Only both with lower 32-bit for now. */
                 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(0)),
-                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x0C0FFEE, 0, 1),
+                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K,
+                        (unsigned long)&fatal_address, 0, 1),
                 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
                 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
         };
@@ -446,7 +451,8 @@ TEST_SIGNAL(KILL_one_arg_one, SIGSYS)
         };
         long ret;
         pid_t parent = getppid();
-        pid_t pid = getpid();
+        struct tms timebuf;
+        clock_t clock = times(&timebuf);
 
         ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
         ASSERT_EQ(0, ret);
@@ -455,17 +461,22 @@ TEST_SIGNAL(KILL_one_arg_one, SIGSYS)
         ASSERT_EQ(0, ret);
 
         EXPECT_EQ(parent, syscall(__NR_getppid));
-        EXPECT_EQ(pid, syscall(__NR_getpid));
-        /* getpid() should never return. */
-        EXPECT_EQ(0, syscall(__NR_getpid, 0x0C0FFEE));
+        EXPECT_LE(clock, syscall(__NR_times, &timebuf));
+        /* times() should never return. */
+        EXPECT_EQ(0, syscall(__NR_times, &fatal_address));
 }
 
 TEST_SIGNAL(KILL_one_arg_six, SIGSYS)
 {
+#ifndef __NR_mmap2
+        int sysno = __NR_mmap;
+#else
+        int sysno = __NR_mmap2;
+#endif
         struct sock_filter filter[] = {
                 BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
                         offsetof(struct seccomp_data, nr)),
-                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
+                BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, sysno, 1, 0),
                 BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
                 /* Only both with lower 32-bit for now. */
                 BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(5)),
@@ -479,7 +490,8 @@ TEST_SIGNAL(KILL_one_arg_six, SIGSYS)
         };
         long ret;
         pid_t parent = getppid();
-        pid_t pid = getpid();
+        int fd;
+        void *map1, *map2;
 
         ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
         ASSERT_EQ(0, ret);
@@ -487,10 +499,22 @@ TEST_SIGNAL(KILL_one_arg_six, SIGSYS)
         ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
         ASSERT_EQ(0, ret);
 
+        fd = open("/dev/zero", O_RDONLY);
+        ASSERT_NE(-1, fd);
+
         EXPECT_EQ(parent, syscall(__NR_getppid));
-        EXPECT_EQ(pid, syscall(__NR_getpid));
-        /* getpid() should never return. */
-        EXPECT_EQ(0, syscall(__NR_getpid, 1, 2, 3, 4, 5, 0x0C0FFEE));
+        map1 = (void *)syscall(sysno,
+                NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, PAGE_SIZE);
+        EXPECT_NE(MAP_FAILED, map1);
+        /* mmap2() should never return. */
+        map2 = (void *)syscall(sysno,
+                 NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, 0x0C0FFEE);
+        EXPECT_EQ(MAP_FAILED, map2);
+
+        /* The test failed, so clean up the resources. */
+        munmap(map1, PAGE_SIZE);
+        munmap(map2, PAGE_SIZE);
+        close(fd);
 }
 
 /* TODO(wad) add 64-bit versus 32-bit arg tests. */