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memory management: add more protection against corruption

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Matheus
2023-07-23 01:06:22 -03:00
parent 6c3164c958
commit a3da864de8
3 changed files with 34 additions and 6 deletions
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kernel-src/mm/alloc.c
+19 -3
View File
@@ -7,16 +7,31 @@
// ptr: data capacity (allocsizes size)
// ptr + sizeof(size_t): current size
// ptr + sizeof(size_t) * 2: data
// ptr + datasize: poison value
#define USE_POISON 0
#define POISON_VALUE 0xdeadbeefbadc0ffel
#define CACHE_COUNT 12
#define CAPACITY_SIZE(cache) cache->size - sizeof(size_t) * 2 - USE_POISON * sizeof(size_t)
static size_t allocsizes[CACHE_COUNT] = {32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536};
static scache_t *caches[CACHE_COUNT];
static void initarea(scache_t *cache, void *obj) {
size_t *ptr = obj;
*ptr = cache->size - sizeof(size_t) * 2;
*ptr = CAPACITY_SIZE(cache);
memset(ptr + 2, 0, *ptr);
#if USE_POISON == 1
*((size_t *)((uintptr_t)obj + cache->size - sizeof(size_t))) = POISON_VALUE;
#endif
}
static void dtor(scache_t *cache, void *obj) {
#if USE_POISON == 1
__assert(*(size_t *)((uintptr_t)obj + cache->size - sizeof(size_t)) == POISON_VALUE);
#endif
initarea(cache, obj);
}
static scache_t *getcachefromsize(size_t size) {
@@ -34,9 +49,10 @@ static scache_t *getcachefromsize(size_t size) {
void *alloc(size_t size) {
scache_t *cache = getcachefromsize(size);
size_t *ret = slab_allocate(cache);
*(ret + 1) = size;
if (ret == NULL)
return NULL;
__assert(*ret == CAPACITY_SIZE(cache));
*(ret + 1) = size;
return ret + 2;
}
@@ -81,7 +97,7 @@ void *realloc(void *ptr, size_t size) {
void alloc_init() {
for (int i = 0; i < CACHE_COUNT; ++i) {
caches[i] = slab_newcache(allocsizes[i] + sizeof(size_t) * 2, 0, initarea, initarea);
caches[i] = slab_newcache(allocsizes[i] + sizeof(size_t) * 2 + sizeof(size_t) * USE_POISON, 0, initarea, dtor);
__assert(caches[i]);
}
}
kernel-src/mm/pmm.c
+13 -1
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@@ -42,6 +42,16 @@ static inline void bmset(void *addr, uint64_t v) {
bitmap[entry] = entryval;
}
static inline bool bmget(void *addr) {
uintmax_t page = (uintptr_t)addr / PAGE_SIZE;
uintmax_t entry = page / 64;
uintmax_t offset = page % 64;
uint64_t entryval = bitmap[entry];
entryval &= ((uint64_t)1 << offset);
return entryval;
}
static uintmax_t getfreearea(bmsection_t *section, size_t size) {
uintmax_t result = 0;
uintmax_t found = 0;
@@ -112,8 +122,10 @@ void pmm_free(void *addr, size_t size) {
if ((uintptr_t)addr / PAGE_SIZE < bmsections[i].searchstart)
bmsections[i].searchstart = (uintptr_t)addr / PAGE_SIZE;
for (uintmax_t j = 0; j < size; ++j)
for (uintmax_t j = 0; j < size; ++j) {
__assert(bmget((void *)((page + j) * PAGE_SIZE)) == false);
bmset((void *)((page + j) * PAGE_SIZE), 1);
}
spinlock_release(&bmsections[i].lock);
__atomic_sub_fetch(&used, 1, __ATOMIC_SEQ_CST);
kernel-src/mm/slab.c
+2 -2
View File
@@ -87,10 +87,10 @@ static void *takeobject(scache_t *cache, slab_t *slab) {
if (cache->size < SLAB_INDIRECT_CUTOFF) {
void *addr = (void *)objend;
void *base = (void *)ROUND_DOWN((uintptr_t)slab, PAGE_SIZE);
__assert(addr > base && addr < (void *)slab);
__assert(addr >= base && addr < (void *)slab);
} else {
void *addr = slab->base + ((uintptr_t)objend - ROUND_DOWN((uintptr_t)slab, PAGE_SIZE)) / sizeof(void **) * cache->truesize;
__assert(addr > slab->base && (uintptr_t)addr < (uintptr_t)slab->base + cache->slabobjcount * cache->truesize);
__assert(addr >= slab->base && (uintptr_t)addr < (uintptr_t)slab->base + cache->slabobjcount * cache->truesize);
}
#endif