85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
#ifndef JEMALLOC_INTERNAL_GUARD_H
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#define JEMALLOC_INTERNAL_GUARD_H
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#include "jemalloc/internal/ehooks.h"
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#include "jemalloc/internal/emap.h"
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#define PAGE_GUARDS_SIZE (2 * PAGE)
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#define SAN_GUARD_LARGE_EVERY_N_EXTENTS_DEFAULT 0
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#define SAN_GUARD_SMALL_EVERY_N_EXTENTS_DEFAULT 0
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/* 0 means disabled, i.e. never guarded. */
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extern size_t opt_san_guard_large;
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extern size_t opt_san_guard_small;
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void san_guard_pages(tsdn_t *tsdn, ehooks_t *ehooks, edata_t *edata,
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emap_t *emap);
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void san_unguard_pages(tsdn_t *tsdn, ehooks_t *ehooks, edata_t *edata,
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emap_t *emap);
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/*
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* Unguard the extent, but don't modify emap boundaries. Must be called on an
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* extent that has been erased from emap and shouldn't be placed back.
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*/
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void san_unguard_pages_pre_destroy(tsdn_t *tsdn, ehooks_t *ehooks,
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edata_t *edata, emap_t *emap);
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void tsd_san_init(tsd_t *tsd);
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static inline bool
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san_enabled(void) {
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return (opt_san_guard_large != 0 || opt_san_guard_small != 0);
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}
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static inline bool
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san_large_extent_decide_guard(tsdn_t *tsdn, ehooks_t *ehooks, size_t size,
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size_t alignment) {
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if (opt_san_guard_large == 0 || ehooks_guard_will_fail(ehooks) ||
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tsdn_null(tsdn)) {
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return false;
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}
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tsd_t *tsd = tsdn_tsd(tsdn);
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uint64_t n = tsd_san_extents_until_guard_large_get(tsd);
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assert(n >= 1);
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if (n > 1) {
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/*
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* Subtract conditionally because the guard may not happen due
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* to alignment or size restriction below.
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*/
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*tsd_san_extents_until_guard_largep_get(tsd) = n - 1;
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}
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if (n == 1 && (alignment <= PAGE) &&
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(size + PAGE_GUARDS_SIZE <= SC_LARGE_MAXCLASS)) {
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*tsd_san_extents_until_guard_largep_get(tsd) =
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opt_san_guard_large;
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return true;
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} else {
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assert(tsd_san_extents_until_guard_large_get(tsd) >= 1);
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return false;
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}
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}
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static inline bool
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san_slab_extent_decide_guard(tsdn_t *tsdn, ehooks_t *ehooks) {
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if (opt_san_guard_small == 0 || ehooks_guard_will_fail(ehooks) ||
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tsdn_null(tsdn)) {
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return false;
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}
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tsd_t *tsd = tsdn_tsd(tsdn);
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uint64_t n = tsd_san_extents_until_guard_small_get(tsd);
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assert(n >= 1);
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if (n == 1) {
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*tsd_san_extents_until_guard_smallp_get(tsd) =
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opt_san_guard_small;
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return true;
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} else {
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*tsd_san_extents_until_guard_smallp_get(tsd) = n - 1;
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assert(tsd_san_extents_until_guard_small_get(tsd) >= 1);
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return false;
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}
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}
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#endif /* JEMALLOC_INTERNAL_GUARD_H */
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