enable important signals in master initialization (#931)

Enable SIGBUS, SIGFPE, SIGILL and SIGSEGV on master initialization Also fix sigsegv in regex initialization and add tests
VKCOM · Nov 3, 2023 · 443616c · 443616c
1 parent 8ae1454
commit 443616c
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Showing 5 changed files with 32 additions and 10 deletions.
diff --git a/common/dl-utils-lite.cpp b/common/dl-utils-lite.cpp
@@ -23,6 +23,7 @@
 #include <unistd.h>
 #include <dirent.h>
 
+#include "common/server/crash-dump.h"
 #include "common/stats/provider.h"
 #include "common/wrappers/pathname.h"
 
@@ -147,6 +148,15 @@ void dl_restore_signal_mask () {
 void dl_block_all_signals () {
   sigset_t mask;
   sigfillset (&mask);
+  // According linux man sigprocmask page
+  // if SIGBUS, SIGFPE, SIGILL, or SIGSEGV are generated while they are blocked, the result is undefined,
+  // unless the signal was generated by kill(2), sigqueue(3), or raise(3).
+  sigdelset(&mask, SIGSEGV);
+  sigdelset(&mask, SIGBUS);
+  sigdelset(&mask, SIGFPE);
+  sigdelset(&mask, SIGILL);
+  // Allow SIGQUIT to generate coredump in signal handlers
+  sigdelset(&mask, SIGQUIT);
   int err = sigprocmask (SIG_SETMASK, &mask, &old_mask);
   old_mask_inited = 1;
   dl_passert (err != -1, "failed to block all signals");
@@ -160,16 +170,21 @@ void dl_allow_all_signals () {
   dl_passert (err != -1, "failed to allow all signals");
 }
 
-static void runtime_handler (const int sig) {
-  fprintf (stderr, "%s caught, terminating program\n", sig == SIGSEGV ? "SIGSEGV" : "SIGABRT");
+static void runtime_handler (const int sig, siginfo_t *info __attribute__((unused)), void *ucontext) {
+  fprintf (stderr, "%s caught, terminating program\n", strsignal(sig));
+  crash_dump_write(static_cast<ucontext_t *>(ucontext));
   dl_print_backtrace();
   dl_print_backtrace_gdb();
+  raise(SIGQUIT);
   _exit (EXIT_FAILURE);
 }
 
 void dl_set_default_handlers () {
-  dl_signal (SIGSEGV, runtime_handler);
-  dl_signal (SIGABRT, runtime_handler);
+  dl_sigaction(SIGSEGV, nullptr, dl_get_empty_sigset(), SA_SIGINFO | SA_ONSTACK | SA_RESTART, runtime_handler);
+  dl_sigaction(SIGBUS, nullptr, dl_get_empty_sigset(), SA_SIGINFO | SA_ONSTACK | SA_RESTART, runtime_handler);
+  dl_sigaction(SIGFPE, nullptr, dl_get_empty_sigset(), SA_SIGINFO | SA_ONSTACK | SA_RESTART, runtime_handler);
+  dl_sigaction(SIGILL, nullptr, dl_get_empty_sigset(), SA_SIGINFO | SA_ONSTACK | SA_RESTART, runtime_handler);
+  dl_sigaction(SIGABRT, nullptr, dl_get_empty_sigset(), SA_SIGINFO | SA_ONSTACK | SA_RESTART, runtime_handler);
 }
 
 char *dl_pstr (char const *msg, ...) {

diff --git a/runtime/datetime/timelib_wrapper.cpp b/runtime/datetime/timelib_wrapper.cpp
@@ -8,6 +8,7 @@
 
 #include "common/containers/final_action.h"
 #include "common/smart_ptrs/singleton.h"
+#include "server/php-engine-vars.h"
 
 // these constants are a part of the private timelib API, but PHP uses them internally;
 // we define them here locally
@@ -214,7 +215,7 @@ std::pair<int64_t, bool> php_timelib_strtotime(const string &tz_name, const stri
     return {0, false};
   }
 
-  bool use_heap_memory = (dl::get_script_memory_stats().memory_limit == 0);
+  bool use_heap_memory = (process_type == ProcessType::master);
   auto malloc_replacement_guard = make_malloc_replacement_with_script_allocator(!use_heap_memory);
 
   timelib_time *now = timelib_time_ctor();

diff --git a/runtime/regexp.cpp b/runtime/regexp.cpp
@@ -12,6 +12,7 @@
 #include "common/unicode/utf8-utils.h"
 
 #include "runtime/critical_section.h"
+#include "server/php-engine-vars.h"
 
 int64_t preg_replace_count_dummy;
 
@@ -314,7 +315,7 @@ void regexp::init(const string &regexp_string, const char *function, const char
   static array<regexp *> *regexp_cache = (array<regexp *> *)regexp_cache_storage;
   static long long regexp_last_query_num = -1;
 
-  use_heap_memory = (dl::get_script_memory_stats().memory_limit == 0);
+  use_heap_memory = (process_type == ProcessType::master);
 
   if (!use_heap_memory) {
     if (dl::query_num != regexp_last_query_num) {
@@ -411,7 +412,7 @@ void regexp::init(const char *regexp_string, int64_t regexp_len, const char *fun
 
   static_SB.clean().append(regexp_string + 1, static_cast<size_t>(regexp_end - 1));
 
-  use_heap_memory = (dl::get_script_memory_stats().memory_limit == 0);
+  use_heap_memory = (process_type == ProcessType::master);
 
   auto malloc_replacement_guard = make_malloc_replacement_with_script_allocator(!use_heap_memory);
 
@@ -590,7 +591,7 @@ void regexp::clean() {
   subpatterns_count = 0;
   named_subpatterns_count = 0;
   is_utf8 = false;
-  use_heap_memory = false;
+  use_heap_memory = (process_type == ProcessType::master);
 
   if (pcre_regexp != nullptr) {
     pcre_free(pcre_regexp);

diff --git a/server/php-engine.cpp b/server/php-engine.cpp
@@ -2322,8 +2322,6 @@ void init_default() {
     kprintf ("fatal: not enough workers for general purposes\n");
     exit(1);
   }
-
-  dl_set_default_handlers();
   now = (int)time(nullptr);
 
   pid = getpid();
@@ -2365,6 +2363,7 @@ void init_default() {
 
 int run_main(int argc, char **argv, php_mode mode) {
   init_version_string(NAME_VERSION);
+  dl_set_default_handlers();
   dl_block_all_signals();
 #if !ASAN_ENABLED
   set_core_dump_rlimit(1LL << 40);

diff --git a/tests/phpt/regexp/008_preg_errors.php b/tests/phpt/regexp/008_preg_errors.php
@@ -1,6 +1,11 @@
 @ok
 <?php
 
+function test_static_preg_errors() {
+  var_dump(preg_match('[ \(\)+-]/', 'simple', $matches));
+  var_dump(preg_match('[\]sigsegv', 'simple', $matches));
+}
+
 function test_preg_errors_constants() {
   var_dump(PREG_NO_ERROR);
   var_dump(PREG_INTERNAL_ERROR);
@@ -66,6 +71,7 @@ function test_preg_errors_offset() {
   var_dump(preg_last_error() == PREG_BAD_UTF8_ERROR);
 }
 
+test_static_preg_errors();
 test_preg_errors_constants();
 test_preg_errors();
 test_preg_errors_offset();