DivestOS/Patches/Common/android_external_hardened_malloc/0003-Broken_Audio.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Thu, 28 May 2020 20:19:14 -0400
Subject: [PATCH] workaround for audio service sorting bug
---
h_malloc.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/h_malloc.c b/h_malloc.c
index 6c3b148..4090b0c 100644
--- a/h_malloc.c
+++ b/h_malloc.c
@@ -83,6 +83,7 @@ static union {
bool zero_on_free;
bool purge_slabs;
bool region_quarantine_protect;
+ bool slot_randomize;
};
char padding[PAGE_SIZE];
} ro __attribute__((aligned(PAGE_SIZE)));
@@ -386,7 +387,7 @@ static u64 get_mask(size_t slots) {
}
static size_t get_free_slot(struct random_state *rng, size_t slots, const struct slab_metadata *metadata) {
- if (SLOT_RANDOMIZE) {
+ if (ro.slot_randomize) {
// randomize start location for linear search (uniform random choice is too slow)
size_t random_index = get_random_u16_uniform(rng, slots);
size_t first_bitmap = random_index / U64_WIDTH;
@@ -1218,6 +1219,12 @@ COLD static void handle_bugs(void) {
ro.purge_slabs = false;
ro.region_quarantine_protect = false;
}
+
+ // DeviceDescriptor sorting wrongly relies on malloc addresses
+ const char audio_service[] = "/system/bin/audioserver";
+ if (strcmp(audio_service, path) == 0) {
+ ro.slot_randomize = false;
+ }
}
static struct mutex init_lock = MUTEX_INITIALIZER;
@@ -1238,6 +1245,7 @@ COLD static void init_slow_path(void) {
ro.purge_slabs = true;
ro.zero_on_free = ZERO_ON_FREE;
ro.region_quarantine_protect = true;
+ ro.slot_randomize = SLOT_RANDOMIZE;
handle_bugs();
if (unlikely(sysconf(_SC_PAGESIZE) != PAGE_SIZE)) {