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dqn: Reduce ASAN guard size to 128 bytes, make it configurable

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This commit is contained in:
doyle 2023-08-29 22:57:31 +10:00
parent 85c0fdf5fd
commit b624ef1da5
4 changed files with 19 additions and 8 deletions
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5
dqn.h
View File

@ -246,6 +246,11 @@
//
// DQN_ASAN_VET_POISON 1
//
// - Define this macro to the size of the guard memory reserved before and after
// allocations made that are poisoned to protect against out-of-bounds memory
// accesses. By default the library sets the guard to 128 bytes.
//
// DQN_ASAN_POISON_GUARD_SIZE 128
// NOTE: Dqn_Strings ===============================================================================
// [$CSTR] Dqn_CString8 | | C-string helpers

8
dqn_debug.h
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@ -38,9 +38,13 @@
#define DQN_ASAN_POISON_VET 0
#endif
#if !defined(DQN_ASAN_POISON_ALIGNMENT)
#define DQN_ASAN_POISON_ALIGNMENT 8
#if !defined(DQN_ASAN_POISON_GUARD_SIZE)
#define DQN_ASAN_POISON_GUARD_SIZE 128
#endif
static_assert(Dqn_IsPowerOfTwoAligned(DQN_ASAN_POISON_GUARD_SIZE, DQN_ASAN_POISON_ALIGNMENT),
"ASAN poison guard size must be a power-of-two and aligned to ASAN's alignment"
"requirement (8 bytes)");
// NOTE: MSVC does not support the feature detection macro for instance so we
// compile it out
@ -48,7 +52,7 @@
#define __has_feature(x) 0
#endif
// NOTE: [$ASAN] Dqn_Asan ========================================================================== ===
// NOTE: [$ASAN] Dqn_Asan ==========================================================================
#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
#include <sanitizer/asan_interface.h>
#endif

4
dqn_helpers.cpp
View File

@ -844,8 +844,10 @@ DQN_API Dqn_Library *Dqn_Library_Init()
Dqn_Log_DebugF("Dqn Library initialised:\n");
Dqn_Print_StdLnF(Dqn_PrintStd_Err, " OS Page Size/Alloc Granularity: %$$_I32u/%$$_I32u", result->os_page_size, result->os_alloc_granularity);
if (DQN_ASAN_POISON)
if (DQN_ASAN_POISON) {
Dqn_Print_StdLnF(Dqn_PrintStd_Err, " ASAN manual poisoning%s", DQN_ASAN_VET_POISON ? " (+vet sanity checks)" : "");
Dqn_Print_StdLnF(Dqn_PrintStd_Err, " ASAN poison guard size: %$$_I32u", DQN_ASAN_POISON_GUARD_SIZE);
}
#if defined(DQN_LEAK_TRACING)
Dqn_Print_StdLnF(Dqn_PrintStd_Err, " Allocation leak tracing");

6
dqn_memory.cpp
View File

@ -179,7 +179,7 @@ DQN_API Dqn_MemBlockSizeRequiredResult Dqn_MemBlock_SizeRequired(Dqn_MemBlock co
// is always guarded with poison-ed memory to prevent read/writes behind
// the block of memory.
if ((block_flags & Dqn_MemBlockFlag_AllocsAreContiguous) == 0) {
result.alloc_size = Dqn_AlignUpPowerOfTwo(size + g_dqn_library->os_page_size, DQN_ASAN_POISON_ALIGNMENT);
result.alloc_size = Dqn_AlignUpPowerOfTwo(size + DQN_ASAN_POISON_GUARD_SIZE, DQN_ASAN_POISON_ALIGNMENT);
}
ptr_alignment = DQN_MAX(alignment, DQN_ASAN_POISON_ALIGNMENT);
}
@ -199,7 +199,7 @@ DQN_API Dqn_MemBlockSizeRequiredResult Dqn_MemBlock_SizeRequired(Dqn_MemBlock co
Dqn_usize Dqn_MemBlock_MetadataSize()
{
Dqn_usize init_poison_page = DQN_ASAN_POISON ? g_dqn_library->os_page_size : 0;
Dqn_usize init_poison_page = DQN_ASAN_POISON ? DQN_ASAN_POISON_GUARD_SIZE : 0;
Dqn_usize poison_alignment = DQN_ASAN_POISON ? DQN_ASAN_POISON_ALIGNMENT : 0;
Dqn_usize result = Dqn_AlignUpPowerOfTwo(sizeof(Dqn_MemBlock), poison_alignment) + init_poison_page;
return result;
@ -236,7 +236,7 @@ DQN_API Dqn_MemBlock *Dqn_MemBlock_Init(Dqn_usize reserve, Dqn_usize commit, uin
DQN_ASSERT(Dqn_IsPowerOfTwoAligned(result->data, DQN_ASAN_POISON_ALIGNMENT));
DQN_ASSERT(Dqn_IsPowerOfTwoAligned(result->size, DQN_ASAN_POISON_ALIGNMENT));
void *poison_ptr = DQN_CAST(void *)Dqn_AlignUpPowerOfTwo(DQN_CAST(char *)result + sizeof(Dqn_MemBlock), DQN_ASAN_POISON_ALIGNMENT);
Dqn_usize bytes_to_poison = g_dqn_library->os_page_size + result->size;
Dqn_usize bytes_to_poison = DQN_ASAN_POISON_GUARD_SIZE + result->size;
Dqn_ASAN_PoisonMemoryRegion(poison_ptr, bytes_to_poison);
}
}