This test would erroneously fail the /proc/$PID/maps case if vsyscall=xonly since the existing probe of the vsyscall page only succeeds if the process has read permissions. Fix this by checking for either no vsyscall mapping OR an execute-only vsyscall mapping in the case were probing the vsyscall page segfaults.
Signed-off-by: Dylan Hatch dylanbhatch@google.com --- tools/testing/selftests/proc/proc-pid-vm.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/proc/proc-pid-vm.c b/tools/testing/selftests/proc/proc-pid-vm.c index 28604c9f805c..5ca85520131f 100644 --- a/tools/testing/selftests/proc/proc-pid-vm.c +++ b/tools/testing/selftests/proc/proc-pid-vm.c @@ -213,9 +213,12 @@ static int make_exe(const uint8_t *payload, size_t len)
static bool g_vsyscall = false;
-static const char str_vsyscall[] = +static const char str_vsyscall_rx[] = "ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n";
+static const char str_vsyscall_x[] = +"ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]\n"; + #ifdef __x86_64__ static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___) { @@ -261,6 +264,7 @@ int main(void) int exec_fd;
vsyscall(); + const char *str_vsyscall = g_vsyscall ? str_vsyscall_rx : str_vsyscall_x;
atexit(ate);
@@ -314,7 +318,8 @@ int main(void)
/* Test /proc/$PID/maps */ { - const size_t len = strlen(buf0) + (g_vsyscall ? strlen(str_vsyscall) : 0); + const size_t len_buf0 = strlen(buf0); + const size_t len_vsys = strlen(str_vsyscall); char buf[256]; ssize_t rv; int fd; @@ -325,11 +330,16 @@ int main(void) return 1; } rv = read(fd, buf, sizeof(buf)); - assert(rv == len); - assert(memcmp(buf, buf0, strlen(buf0)) == 0); if (g_vsyscall) { - assert(memcmp(buf + strlen(buf0), str_vsyscall, strlen(str_vsyscall)) == 0); + assert(rv == len_buf0 + len_vsys); + } else { + /* If vsyscall isn't readable, it's either x-only or not mapped at all */ + assert(rv == len_buf0 + len_vsys || rv == len_buf0); } + assert(memcmp(buf, buf0, len_buf0) == 0); + /* Check for vsyscall mapping if buf is long enough */ + if (rv == len_buf0 + len_vsys) + assert(memcmp(buf + len_buf0, str_vsyscall, len_vsys) == 0); }
/* Test /proc/$PID/smaps */