mirror of
https://github.com/GrapheneOS/hardened_malloc.git
synced 2025-04-19 22:10:19 +02:00
52fcaf55d6
- tag slab allocations with [1..14] tags - tag freed slab allocations with the "15" tag value to detect accesses to freed slab memory - when generating tag value for a slab slot, always exclude most recent tag value for that slot (to make use-after-free detection more reliable) and most recent tag values of its immediate neighbors (to detect linear overflows and underflows)
52 lines
898 B
C
52 lines
898 B
C
#ifndef MEMTAG_H
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#define MEMTAG_H
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#include "util.h"
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#ifdef HAS_ARM_MTE
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#include "arm_mte.h"
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#define MEMTAG 1
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#define RESERVED_TAG 15
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#define TAG_WIDTH 4
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#endif
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#ifdef MEMTAG
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extern bool __is_memtag_enabled;
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#endif
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static inline bool is_memtag_enabled(void) {
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#ifdef MEMTAG
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return __is_memtag_enabled;
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#else
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return false;
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#endif
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}
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static inline void *untag_pointer(void *ptr) {
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#ifdef HAS_ARM_MTE
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const uintptr_t mask = UINTPTR_MAX >> 8;
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return (void *) ((uintptr_t) ptr & mask);
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#else
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return ptr;
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#endif
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}
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static inline void *set_pointer_tag(void *ptr, u8 tag) {
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#ifdef HAS_ARM_MTE
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return (void *) (((uintptr_t) tag << 56) | (uintptr_t) untag_pointer(ptr));
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#else
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(void) tag;
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return ptr;
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#endif
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}
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static inline u8 get_pointer_tag(void *ptr) {
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#ifdef HAS_ARM_MTE
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return (((uintptr_t) ptr) >> 56) & 0xf;
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#else
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(void) ptr;
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return 0;
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#endif
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}
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#endif
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