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Fix stack memory, undefined behavior, etc.

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This commit is contained in:
Justine Tunney 2023-08-15 19:09:35 -07:00
parent 110559ce6a
commit 507d7a0b0b
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GPG key ID: BE714B4575D6E328
11 changed files with 41 additions and 186 deletions
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2
libc/runtime/mapstack.c
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@ -45,7 +45,7 @@ void *NewCosmoStack(void) {
MAP_STACK | MAP_ANONYMOUS, -1, 0)) != MAP_FAILED) {
if (IsAsan()) {
__asan_poison(p + GetStackSize() - 16, 16, kAsanStackOverflow);
__asan_poison(p, 4096, kAsanStackOverflow);
__asan_poison(p, GetGuardSize(), kAsanStackOverflow);
}
return p;
} else {

4
libc/runtime/mmap.c
View file

@ -372,13 +372,13 @@ dontasan inline void *__mmap_unlocked(void *addr, size_t size, int prot,
if ((dm = sys_mmap(p + size - SIGSTKSZ, SIGSTKSZ, prot,
f | MAP_GROWSDOWN_linux, fd, off))
.addr != MAP_FAILED) {
npassert(sys_mmap(p, page_size, PROT_NONE,
npassert(sys_mmap(p, GetGuardSize(), PROT_NONE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0)
.addr == p);
dm.addr = p;
p = __finish_memory(p, size, prot, flags, fd, off, f, x, n, dm);
if (IsAsan() && p != MAP_FAILED) {
__asan_poison(p, page_size, kAsanStackOverflow);
__asan_poison(p, GetGuardSize(), kAsanStackOverflow);
}
return p;
} else if (errno == ENOTSUP) {

21
libc/runtime/stack.h
View file

@ -81,9 +81,18 @@ extern char ape_stack_memsz[] __attribute__((__weak__));
extern char ape_stack_align[] __attribute__((__weak__));
/**
* Returns size of stack, which is always a two power.
* Returns preferred size and alignment of thread stack.
*
* This will always be equal to `PTHREAD_STACK_MIN`.
*/
#define GetStackSize() ((uintptr_t)ape_stack_memsz)
#define GetStackSize() 262144
/**
* Returns preferred stack guard size.
*
* This is the max cpu page size of supported architectures.
*/
#define GetGuardSize() 16384
/**
* Returns address of bottom of stack.
@ -124,9 +133,13 @@ extern char ape_stack_align[] __attribute__((__weak__));
/**
* Returns true if at least `n` bytes of stack are available.
*/
#define HaveStackMemory(n) \
((intptr_t)__builtin_frame_address(0) >= GetStackAddr() + 16384 + (n))
#define HaveStackMemory(n) \
((intptr_t)__builtin_frame_address(0) >= \
GetStackAddr() + GetGuardSize() + (n))
/**
* Extends stack memory by poking large allocations.
*/
forceinline void CheckLargeStackAllocation(void *p, ssize_t n) {
for (; n > 0; n -= 4096) {
((char *)p)[n - 1] = 0;