mirror of
https://github.com/GrapheneOS/hardened_malloc.git
synced 2024-10-01 01:36:01 -04:00
get rid of canary_value when canaries are disabled
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parent
346529574d
commit
5f32942263
50
h_malloc.c
50
h_malloc.c
@ -92,7 +92,9 @@ struct slab_metadata {
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u64 bitmap[4];
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struct slab_metadata *next;
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struct slab_metadata *prev;
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#if SLAB_CANARY
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u64 canary_value;
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#endif
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#ifdef SLAB_METADATA_COUNT
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u16 count;
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#endif
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@ -450,16 +452,30 @@ static void write_after_free_check(const char *p, size_t size) {
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}
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}
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static const u64 canary_mask = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ?
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0xffffffffffffff00UL :
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0x00ffffffffffffffUL;
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static void set_slab_canary_value(UNUSED struct slab_metadata *metadata, UNUSED struct random_state *rng) {
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#if SLAB_CANARY
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static const u64 canary_mask = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ?
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0xffffffffffffff00UL :
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0x00ffffffffffffffUL;
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static void set_canary(const struct slab_metadata *metadata, void *p, size_t size) {
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memcpy((char *)p + size - canary_size, &metadata->canary_value, canary_size);
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metadata->canary_value = get_random_u64(rng) & canary_mask;
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#endif
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}
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static u64 get_random_canary(struct random_state *rng) {
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return get_random_u64(rng) & canary_mask;
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static void set_canary(UNUSED const struct slab_metadata *metadata, UNUSED void *p, UNUSED size_t size) {
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#if SLAB_CANARY
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memcpy((char *)p + size - canary_size, &metadata->canary_value, canary_size);
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#endif
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}
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static void check_canary(UNUSED const struct slab_metadata *metadata, UNUSED const void *p, UNUSED size_t size) {
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#if SLAB_CANARY
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u64 canary_value;
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memcpy(&canary_value, (const char *)p + size - canary_size, canary_size);
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if (unlikely(canary_value != metadata->canary_value)) {
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fatal_error("canary corrupted");
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}
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#endif
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}
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static inline void stats_small_allocate(UNUSED struct size_class *c, UNUSED size_t size) {
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@ -525,7 +541,7 @@ static inline void *allocate_small(unsigned arena, size_t requested_size) {
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if (c->free_slabs_head != NULL) {
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struct slab_metadata *metadata = c->free_slabs_head;
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metadata->canary_value = get_random_canary(&c->rng);
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set_slab_canary_value(metadata, &c->rng);
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void *slab = get_slab(c, slab_size, metadata);
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if (requested_size && memory_protect_rw(slab, slab_size)) {
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@ -561,7 +577,7 @@ static inline void *allocate_small(unsigned arena, size_t requested_size) {
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mutex_unlock(&c->lock);
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return NULL;
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}
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metadata->canary_value = get_random_canary(&c->rng);
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set_slab_canary_value(metadata, &c->rng);
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c->partial_slabs = slots > 1 ? metadata : NULL;
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void *slab = get_slab(c, slab_size, metadata);
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@ -673,13 +689,7 @@ static inline void deallocate_small(void *p, const size_t *expected_size) {
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}
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if (!is_zero_size) {
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if (SLAB_CANARY) {
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u64 canary_value;
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memcpy(&canary_value, (char *)p + size - canary_size, canary_size);
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if (unlikely(canary_value != metadata->canary_value)) {
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fatal_error("canary corrupted");
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}
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}
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check_canary(metadata, p, size);
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if (ZERO_ON_FREE) {
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memset(p, 0, size - canary_size);
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@ -1589,12 +1599,8 @@ static inline void memory_corruption_check_small(const void *p) {
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fatal_error("invalid malloc_usable_size");
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}
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if (!is_zero_size && SLAB_CANARY) {
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u64 canary_value;
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memcpy(&canary_value, (const char *)p + size - canary_size, canary_size);
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if (unlikely(canary_value != metadata->canary_value)) {
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fatal_error("canary corrupted");
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}
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if (!is_zero_size) {
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check_canary(metadata, p, size);
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}
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#if SLAB_QUARANTINE
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