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Kernel: Assert if rounding-up-to-page-size would wrap around to 0

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If we try to align a number above 0xfffff000 to the next multiple of
the page size (4 KiB), it would wrap around to 0. This is most likely
never what we want, so let's assert if that happens.
This commit is contained in:
Andreas Kling
2021-02-14 09:57:19 +01:00
parent 198d641808
commit 09b1b09c19
19 changed files with 67 additions and 40 deletions
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22
Kernel/Syscalls/mmap.cpp
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@@ -160,7 +160,10 @@ void* Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> user_params)
if (alignment & ~PAGE_MASK)
return (void*)-EINVAL;
if (!is_user_range(VirtualAddress(addr), PAGE_ROUND_UP(size)))
if (page_round_up_would_wrap(size))
return (void*)-EINVAL;
if (!is_user_range(VirtualAddress(addr), page_round_up(size)))
return (void*)-EFAULT;
String name;
@@ -204,7 +207,7 @@ void* Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> user_params)
Optional<Range> range;
if (map_randomized) {
range = space().page_directory().range_allocator().allocate_randomized(PAGE_ROUND_UP(size), alignment);
range = space().page_directory().range_allocator().allocate_randomized(page_round_up(size), alignment);
} else {
range = space().allocate_range(VirtualAddress(addr), size, alignment);
if (!range.has_value()) {
@@ -272,7 +275,10 @@ int Process::sys$mprotect(void* addr, size_t size, int prot)
REQUIRE_PROMISE(prot_exec);
}
Range range_to_mprotect = { VirtualAddress((FlatPtr)addr & PAGE_MASK), PAGE_ROUND_UP(size) };
if (page_round_up_would_wrap(size))
return -EINVAL;
Range range_to_mprotect = { VirtualAddress((FlatPtr)addr & PAGE_MASK), page_round_up(size) };
if (!range_to_mprotect.size())
return -EINVAL;
@@ -343,7 +349,10 @@ int Process::sys$madvise(void* address, size_t size, int advice)
{
REQUIRE_PROMISE(stdio);
Range range_to_madvise { VirtualAddress((FlatPtr)address & PAGE_MASK), PAGE_ROUND_UP(size) };
if (page_round_up_would_wrap(size))
return -EINVAL;
Range range_to_madvise { VirtualAddress((FlatPtr)address & PAGE_MASK), page_round_up(size) };
if (!range_to_madvise.size())
return -EINVAL;
@@ -415,7 +424,10 @@ int Process::sys$munmap(void* addr, size_t size)
if (!size)
return -EINVAL;
Range range_to_unmap { VirtualAddress(addr), PAGE_ROUND_UP(size) };
if (page_round_up_would_wrap(size))
return -EINVAL;
Range range_to_unmap { VirtualAddress(addr), page_round_up(size) };
if (!is_user_range(range_to_unmap))
return -EFAULT;