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--- libmalloc/libmalloc-425.100.7/src/pgm_malloc.c
+++ libmalloc/libmalloc-374.40.6/src/pgm_malloc.c
@@ -24,6 +24,9 @@
#include "pgm_malloc.h"
#include <TargetConditionals.h>
+#if !TARGET_OS_DRIVERKIT
+# include <dlfcn.h> // dladdr()
+#endif
#include <mach/mach_time.h> // mach_absolute_time()
#include <sys/codesign.h> // csops()
@@ -86,6 +89,7 @@
uint32_t max_metadata;
uint32_t sample_counter_range;
uint32_t min_alignment;
+ bool signal_handler;
bool debug;
uint64_t debug_log_throttle_ms;
@@ -124,27 +128,6 @@
#pragma mark -
-#pragma mark Thread Local Sample Counter
-
-MALLOC_STATIC_ASSERT(sizeof(void *) >= sizeof(uint32_t), "Pointer is used as 32bit counter");
-
-#define TSD_GET_COUNTER() ((uint32_t)_pthread_getspecific_direct(__TSD_MALLOC_PROB_GUARD_SAMPLE_COUNTER))
-#define TSD_SET_COUNTER(val) _pthread_setspecific_direct(__TSD_MALLOC_PROB_GUARD_SAMPLE_COUNTER, (void *)(uintptr_t)val)
-
-static const uint32_t k_no_sample = UINT32_MAX;
-
-void
-pgm_thread_set_disabled(bool disabled)
-{
- if (disabled) {
- TSD_SET_COUNTER(k_no_sample);
- } else {
- TSD_SET_COUNTER(0);
- }
-}
-
-
-#pragma mark -
#pragma mark Decider Functions
// The "decider" functions are performance critical. They should be inlinable and must not lock.
@@ -163,17 +146,15 @@
static inline boolean_t
should_sample_counter(uint32_t counter_range)
{
- uint32_t counter = TSD_GET_COUNTER();
- if (counter == k_no_sample) {
- return false;
- }
+ MALLOC_STATIC_ASSERT(sizeof(void *) >= sizeof(uint32_t), "Pointer is used as 32bit counter");
+ uint32_t counter = (uint32_t)_pthread_getspecific_direct(__TSD_MALLOC_PROB_GUARD_SAMPLE_COUNTER);
// 0 -> regenerate counter; 1 -> sample allocation
if (counter == 0) {
counter = rand_uniform(counter_range);
} else {
counter--;
}
- TSD_SET_COUNTER(counter);
+ _pthread_setspecific_direct(__TSD_MALLOC_PROB_GUARD_SAMPLE_COUNTER, (void *)(uintptr_t)counter);
return counter == 0;
}
#endif
@@ -1132,7 +1113,7 @@
return true;
}
-#if TARGET_OS_WATCH || TARGET_OS_TV
+#if TARGET_OS_WATCH
static bool
is_high_memory_device(void)
{
@@ -1140,9 +1121,6 @@
return platform_hw_memsize() > high_memory;
}
#endif
-
-#define PGM_ALLOW_NON_INTERNAL_ACTIVATION 0
-
bool
pgm_should_enable(bool internal_build)
@@ -1153,18 +1131,14 @@
if (FEATURE_FLAG(ProbGuard, true) && should_activate(internal_build)) {
#if TARGET_OS_OSX || TARGET_OS_IOS
return true;
-#elif TARGET_OS_WATCH || TARGET_OS_TV
- if (is_high_memory_device()) {
- return true;
- }
-#elif PGM_ALLOW_NON_INTERNAL_ACTIVATION
- return true;
-#elif TARGET_OS_DRIVERKIT
- // Never enable for DriverKit
-#else
+#elif TARGET_OS_TV
if (internal_build) {
return true;
}
+#elif TARGET_OS_WATCH
+ if (internal_build && is_high_memory_device()) {
+ return true;
+ }
#endif
}
if (FEATURE_FLAG(ProbGuardAllProcesses, false)) {
@@ -1179,10 +1153,15 @@
return (TARGET_OS_OSX ? 8 : 2) * 1024;
}
+// TODO(yln): uniform sampling is likely not optimal here, since we will tend to
+// sample around the average of our range, which is probably more frequent than
+// what we want. We probably want the average to be less frequent, but still be
+// able to reach the "very frequent" end of our range occassionally. Consider
+// using a geometric (or other weighted distribution) here.
static uint32_t
choose_sample_rate(void)
{
- uint32_t min = 500, max = 5000;
+ uint32_t min = 500, max = 10000;
return rand_uniform(max - min) + min;
}
@@ -1219,7 +1198,8 @@
// Approximate a (1 / sample_rate) chance for sampling; 1 means "always sample".
zone->sample_counter_range = (sample_rate != 1) ? (2 * sample_rate) : 1;
bool strict_alignment = env_var("MallocProbGuardStrictAlignment") ? env_bool("MallocProbGuardStrictAlignment") : FEATURE_FLAG(ProbGuardStrictAlignment, false);
- zone->min_alignment = (strict_alignment && MALLOC_TARGET_64BIT) ? 1 : 16; // Darwin ABI requires 16 byte alignment.
+ zone->min_alignment = strict_alignment ? 1 : 16; // Darwin ABI requires 16 byte alignment.
+ zone->signal_handler = env_bool("MallocProbGuardSignalHandler");
zone->debug = env_bool("MallocProbGuardDebug");
zone->debug_log_throttle_ms = env_uint("MallocProbGuardDebugLogThrottleInMillis", 1000);
@@ -1271,6 +1251,7 @@
init_lock(zone);
}
+static void install_signal_handler(void *unused);
malloc_zone_t *
pgm_create_zone(malloc_zone_t *wrapped_zone)
{
@@ -1282,6 +1263,11 @@
pgm_zone_t *zone = (pgm_zone_t *)my_vm_map(sizeof(pgm_zone_t), VM_PROT_READ_WRITE, VM_MEMORY_MALLOC);
setup_zone(zone, wrapped_zone);
my_vm_protect((vm_address_t)zone, PAGE_MAX_SIZE, VM_PROT_READ);
+
+ if (zone->signal_handler) {
+ static os_once_t once_pred;
+ os_once(&once_pred, NULL, &install_signal_handler);
+ }
return (malloc_zone_t *)zone;
}
@@ -1414,6 +1400,60 @@
#pragma mark -
+#pragma mark Error Printing
+
+static const uint32_t k_buf_len = 1024;
+static void
+get_symbol_and_module_name(vm_address_t addr, char buf[k_buf_len])
+{
+ int success = 0;
+#if !TARGET_OS_DRIVERKIT
+ Dl_info info;
+ success = dladdr((void *)addr, &info);
+ if (success) {
+ snprintf(buf, k_buf_len, "%s (%s)", info.dli_sname, info.dli_fname);
+ }
+#endif
+ if (!success) {
+ snprintf(buf, k_buf_len, "%p", (void *)addr);
+ }
+}
+
+static void
+print_trace(stack_trace_t *trace, const char *label)
+{
+ malloc_report(ASL_LEVEL_ERR, "%s trace (thread %llu, time: %llu):\n", label, trace->thread_id, trace->time);
+ for (uint32_t i = 0; i < trace->num_frames; i++) {
+ char sym_name[k_buf_len];
+ get_symbol_and_module_name(trace->frames[i], sym_name);
+ malloc_report(ASL_LEVEL_ERR, " #%u %s\n", i, sym_name);
+ }
+ malloc_report(ASL_LEVEL_ERR, "\n", label);
+}
+
+static void
+print_report(pgm_report_t *report)
+{
+ malloc_report(ASL_LEVEL_ERR, "ProbGuard: invalid access at 0x%lx\n",
+ report->fault_address);
+ malloc_report(ASL_LEVEL_ERR, "Error type: %s (%s confidence)\n",
+ report->error_type, report->confidence);
+ malloc_report(ASL_LEVEL_ERR, "Nearest allocation: 0x%lx, size: %lu, state: %s\n",
+ report->nearest_allocation, report->allocation_size, report->allocation_state);
+
+ if (report->num_traces >= 1) {
+ print_trace(&report->alloc_trace, "Allocation");
+ if (report->num_traces >= 2) {
+ print_trace(&report->dealloc_trace, "Deallocation");
+ }
+ } else {
+ malloc_report(ASL_LEVEL_ERR, "Allocation stack traces not available. "
+ "Try increasing `MallocProbGuardMetadata` and rerun.\n");
+ }
+}
+
+
+#pragma mark -
#pragma mark Crash Reporter API
static kern_return_t
@@ -1468,6 +1508,65 @@
_malloc_lock_unlock(&crash_reporter_lock);
return kr;
+}
+
+
+#pragma mark -
+#pragma mark Signal Handler
+
+extern malloc_zone_t **malloc_zones;
+static void
+report_error_from_signal_handler(vm_address_t fault_address)
+{
+ pgm_zone_t *zone = (pgm_zone_t *)malloc_zones[0];
+ MALLOC_ASSERT(zone->malloc_zone.size == FN_PTR(pgm_size));
+
+ if (!is_guarded(zone, fault_address)) {
+ return;
+ }
+
+ pgm_report_t report;
+ {
+ trylock(zone); // Best-effort locking to avoid deadlock.
+ diagnose_page_fault(zone, fault_address, &report);
+ unlock(zone);
+ }
+ print_report(&report);
+
+ MALLOC_REPORT_FATAL_ERROR(fault_address, "ProbGuard: invalid access detected");
+}
+
+static struct sigaction prev_sigaction;
+static void
+signal_handler(int sig, siginfo_t *info, void *ucontext)
+{
+ MALLOC_ASSERT(sig == SIGBUS);
+ report_error_from_signal_handler((vm_address_t)info->si_addr);
+
+ // Delegate to previous handler.
+ if (prev_sigaction.sa_flags & SA_SIGINFO) {
+ prev_sigaction.sa_sigaction(sig, info, ucontext);
+ } else if (prev_sigaction.sa_handler == SIG_IGN ||
+ prev_sigaction.sa_handler == SIG_DFL) {
+ // If the previous handler was the default handler, or was ignoring this
+ // signal, install the default handler and re-raise the signal in order to
+ // get a core dump and terminate this process.
+ signal(SIGBUS, SIG_DFL);
+ raise(SIGBUS);
+ } else {
+ prev_sigaction.sa_handler(sig);
+ }
+}
+
+static void
+install_signal_handler(void *unused)
+{
+ struct sigaction act = {
+ .sa_sigaction = &signal_handler,
+ .sa_flags = SA_SIGINFO
+ };
+ int res = sigaction(SIGBUS, &act, &prev_sigaction);
+ MALLOC_ASSERT(res == 0);
}