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Kernel: Handle mmap requests on zero-length data file inodes safely

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Liav A 2022-08-06 21:05:48 +03:00 • committed by Idan Horowitz
parent c88cc8557f
commit 3ad0e1a1d5
5 changed files with 28 additions and 5 deletions
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12
Kernel/Memory/SharedInodeVMObject.cpp
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@ -12,7 +12,17 @@ namespace Kernel::Memory {
ErrorOr<NonnullLockRefPtr<SharedInodeVMObject>> SharedInodeVMObject::try_create_with_inode(Inode& inode)
{
size_t size = inode.size();
if (inode.size() == 0)
return EINVAL;
return try_create_with_inode_and_range(inode, 0, inode.size());
}
ErrorOr<NonnullLockRefPtr<SharedInodeVMObject>> SharedInodeVMObject::try_create_with_inode_and_range(Inode& inode, u64 offset, size_t range_size)
{
// Note: To ensure further allocation of a Region with this VMObject will not complain
// on "smaller" VMObject than the requested Region, we simply take the max size between both values.
auto size = max(inode.size(), (offset + range_size));
VERIFY(size > 0);
if (auto shared_vmobject = inode.shared_vmobject())
return shared_vmobject.release_nonnull();
auto new_physical_pages = TRY(VMObject::try_create_physical_pages(size));