RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-06-01 08:28:11 +00:00
Code Issues Activity Actions

Kernel: Factor out mmap & friends range expansion to a helper function

Browse source 
sys$mmap() and related syscalls must pad to the nearest page boundary
below the base address *and* above the end address of the specified
range. Since we have to do this in many places, let's make a helper.
This commit is contained in:
Andreas Kling 2021-02-18 18:04:58 +01:00
parent 44aeab43a0
commit eb92ec3149
1 changed files with 41 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

57
Kernel/Syscalls/mmap.cpp
View file

@ -267,6 +267,23 @@ void* Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> user_params)
return region->vaddr().as_ptr();
}
static KResultOr<Range> expand_range_to_page_boundaries(FlatPtr address, size_t size)
{
if (page_round_up_would_wrap(size))
return EINVAL;
if ((address + size) < address)
return EINVAL;
if (page_round_up_would_wrap(address + size))
return EINVAL;
auto base = VirtualAddress { address }.page_base();
auto end = page_round_up(address + size);
return Range { base, end - base.get() };
}
int Process::sys$mprotect(void* addr, size_t size, int prot)
{
REQUIRE_PROMISE(stdio);
@ -275,11 +292,11 @@ int Process::sys$mprotect(void* addr, size_t size, int prot)
REQUIRE_PROMISE(prot_exec);
}
if (page_round_up_would_wrap(size))
return -EINVAL;
Range range_to_mprotect = { VirtualAddress((FlatPtr)addr & PAGE_MASK), page_round_up(size) };
auto range_or_error = expand_range_to_page_boundaries((FlatPtr)addr, size);
if (range_or_error.is_error())
return range_or_error.error();
auto range_to_mprotect = range_or_error.value();
if (!range_to_mprotect.size())
return -EINVAL;
@ -349,10 +366,11 @@ int Process::sys$madvise(void* address, size_t size, int advice)
{
REQUIRE_PROMISE(stdio);
if (page_round_up_would_wrap(size))
return -EINVAL;
auto range_or_error = expand_range_to_page_boundaries((FlatPtr)address, size);
if (range_or_error.is_error())
return range_or_error.error();
Range range_to_madvise { VirtualAddress((FlatPtr)address & PAGE_MASK), page_round_up(size) };
auto range_to_madvise = range_or_error.value();
if (!range_to_madvise.size())
return -EINVAL;
@ -408,7 +426,13 @@ int Process::sys$set_mmap_name(Userspace<const Syscall::SC_set_mmap_name_params*
if (name.is_null())
return -EFAULT;
auto* region = space().find_region_from_range({ VirtualAddress(params.addr), params.size });
auto range_or_error = expand_range_to_page_boundaries((FlatPtr)params.addr, params.size);
if (range_or_error.is_error())
return range_or_error.error();
auto range = range_or_error.value();
auto* region = space().find_region_from_range(range);
if (!region)
return -EINVAL;
if (!region->is_mmap())
@ -424,10 +448,11 @@ int Process::sys$munmap(void* addr, size_t size)
if (!size)
return -EINVAL;
if (page_round_up_would_wrap(size))
return -EINVAL;
auto range_or_error = expand_range_to_page_boundaries((FlatPtr)addr, size);
if (range_or_error.is_error())
return range_or_error.error();
Range range_to_unmap { VirtualAddress(addr), page_round_up(size) };
auto range_to_unmap = range_or_error.value();
if (!is_user_range(range_to_unmap))
return -EFAULT;
@ -473,13 +498,13 @@ void* Process::sys$mremap(Userspace<const Syscall::SC_mremap_params*> user_param
if (!copy_from_user(&params, user_params))
return (void*)-EFAULT;
if (page_round_up_would_wrap(params.old_size))
return (void*)-EINVAL;
auto range_or_error = expand_range_to_page_boundaries((FlatPtr)params.old_address, params.old_size);
if (range_or_error.is_error())
return (void*)range_or_error.error().error();
auto old_address = page_round_down(params.old_address);
auto old_size = page_round_up(params.old_size);
auto old_range = range_or_error.value();
auto* old_region = space().find_region_from_range(Range { VirtualAddress { old_address }, old_size });
auto* old_region = space().find_region_from_range(old_range);
if (!old_region)
return (void*)-EINVAL;