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Kernel: Make UserOrKernelBuffer::for_user_buffer() return ErrorOr<T>

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This simplifies EFAULT propagation with TRY(). :^)
This commit is contained in:
Andreas Kling 2021-11-21 12:24:32 +01:00
parent b820ae2828
commit f2c3a41a8f
Notes: sideshowbarker 2024-07-18 00:53:53 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/f2c3a41a8f8
7 changed files with 27 additions and 47 deletions
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12
Kernel/Coredump.cpp
View file

@ -182,16 +182,14 @@ ErrorOr<void> Coredump::write_regions()
auto* page = region->physical_page(i);
uint8_t zero_buffer[PAGE_SIZE] = {};
Optional<UserOrKernelBuffer> src_buffer;
if (page) {
src_buffer = UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region->vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
} else {
auto src_buffer = [&]() -> ErrorOr<UserOrKernelBuffer> {
if (page)
return UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region->vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
// If the current page is not backed by a physical page, we zero it in the coredump file.
// TODO: Do we want to include the contents of pages that have not been faulted-in in the coredump?
// (A page may not be backed by a physical page because it has never been faulted in when the process ran).
src_buffer = UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
}
return UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
}();
TRY(m_description->write(src_buffer.value(), PAGE_SIZE));
}
}

6
Kernel/Syscalls/get_dir_entries.cpp
View file

@ -16,10 +16,8 @@ ErrorOr<FlatPtr> Process::sys$get_dir_entries(int fd, Userspace<void*> user_buff
if (user_size > NumericLimits<ssize_t>::max())
return EINVAL;
auto description = TRY(fds().open_file_description(fd));
auto buffer = UserOrKernelBuffer::for_user_buffer(user_buffer, static_cast<size_t>(user_size));
if (!buffer.has_value())
return EFAULT;
auto count = TRY(description->get_dir_entries(buffer.value(), user_size));
auto buffer = TRY(UserOrKernelBuffer::for_user_buffer(user_buffer, static_cast<size_t>(user_size)));
auto count = TRY(description->get_dir_entries(buffer, user_size));
return count;
}

6
Kernel/Syscalls/getrandom.cpp
View file

@ -20,11 +20,9 @@ ErrorOr<FlatPtr> Process::sys$getrandom(Userspace<void*> buffer, size_t buffer_s
if (buffer_size > NumericLimits<ssize_t>::max())
return EINVAL;
auto data_buffer = UserOrKernelBuffer::for_user_buffer(buffer, buffer_size);
if (!data_buffer.has_value())
return EFAULT;
auto data_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, buffer_size));
return TRY(data_buffer.value().write_buffered<1024>(buffer_size, [&](Bytes bytes) {
return TRY(data_buffer.write_buffered<1024>(buffer_size, [&](Bytes bytes) {
get_good_random_bytes(bytes);
return bytes.size();
}));

18
Kernel/Syscalls/read.cpp
View file

@ -63,10 +63,8 @@ ErrorOr<FlatPtr> Process::sys$readv(int fd, Userspace<const struct iovec*> iov,
int nread = 0;
for (auto& vec : vecs) {
TRY(check_blocked_read(description));
auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
if (!buffer.has_value())
return EFAULT;
auto nread_here = TRY(description->read(buffer.value(), vec.iov_len));
auto buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len));
auto nread_here = TRY(description->read(buffer, vec.iov_len));
nread += nread_here;
}
@ -84,10 +82,8 @@ ErrorOr<FlatPtr> Process::sys$read(int fd, Userspace<u8*> buffer, size_t size)
dbgln_if(IO_DEBUG, "sys$read({}, {}, {})", fd, buffer.ptr(), size);
auto description = TRY(open_readable_file_description(fds(), fd));
TRY(check_blocked_read(description));
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
return EFAULT;
return TRY(description->read(user_buffer.value(), size));
auto user_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, size));
return TRY(description->read(user_buffer, size));
}
ErrorOr<FlatPtr> Process::sys$pread(int fd, Userspace<u8*> buffer, size_t size, Userspace<off_t*> userspace_offset)
@ -107,10 +103,8 @@ ErrorOr<FlatPtr> Process::sys$pread(int fd, Userspace<u8*> buffer, size_t size,
if (!description->file().is_seekable())
return EINVAL;
TRY(check_blocked_read(description));
auto user_buffer = UserOrKernelBuffer::for_user_buffer(buffer, size);
if (!user_buffer.has_value())
return EFAULT;
return TRY(description->read(user_buffer.value(), offset, size));
auto user_buffer = TRY(UserOrKernelBuffer::for_user_buffer(buffer, size));
return TRY(description->read(user_buffer, offset, size));
}
}

12
Kernel/Syscalls/socket.cpp
View file

@ -182,10 +182,8 @@ ErrorOr<FlatPtr> Process::sys$sendmsg(int sockfd, Userspace<const struct msghdr*
auto& socket = *description->socket();
if (socket.is_shut_down_for_writing())
return EPIPE;
auto data_buffer = UserOrKernelBuffer::for_user_buffer((u8*)iovs[0].iov_base, iovs[0].iov_len);
if (!data_buffer.has_value())
return EFAULT;
auto bytes_sent = TRY(socket.sendto(*description, data_buffer.value(), iovs[0].iov_len, flags, user_addr, addr_length));
auto data_buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)iovs[0].iov_base, iovs[0].iov_len));
auto bytes_sent = TRY(socket.sendto(*description, data_buffer, iovs[0].iov_len, flags, user_addr, addr_length));
return bytes_sent;
}
@ -218,11 +216,9 @@ ErrorOr<FlatPtr> Process::sys$recvmsg(int sockfd, Userspace<struct msghdr*> user
if (flags & MSG_DONTWAIT)
description->set_blocking(false);
auto data_buffer = UserOrKernelBuffer::for_user_buffer((u8*)iovs[0].iov_base, iovs[0].iov_len);
if (!data_buffer.has_value())
return EFAULT;
auto data_buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)iovs[0].iov_base, iovs[0].iov_len));
Time timestamp {};
auto result = socket.recvfrom(*description, data_buffer.value(), iovs[0].iov_len, flags, user_addr, user_addr_length, timestamp);
auto result = socket.recvfrom(*description, data_buffer, iovs[0].iov_len, flags, user_addr, user_addr_length, timestamp);
if (flags & MSG_DONTWAIT)
description->set_blocking(original_blocking);

12
Kernel/Syscalls/write.cpp
View file

@ -38,10 +38,8 @@ ErrorOr<FlatPtr> Process::sys$writev(int fd, Userspace<const struct iovec*> iov,
int nwritten = 0;
for (auto& vec : vecs) {
auto buffer = UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len);
if (!buffer.has_value())
return EFAULT;
auto result = do_write(*description, buffer.value(), vec.iov_len);
auto buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len));
auto result = do_write(*description, buffer, vec.iov_len);
if (result.is_error()) {
if (nwritten == 0)
return result.release_error();
@ -104,10 +102,8 @@ ErrorOr<FlatPtr> Process::sys$write(int fd, Userspace<const u8*> data, size_t si
if (!description->is_writable())
return EBADF;
auto buffer = UserOrKernelBuffer::for_user_buffer(data, static_cast<size_t>(size));
if (!buffer.has_value())
return EFAULT;
return do_write(*description, buffer.value(), size);
auto buffer = TRY(UserOrKernelBuffer::for_user_buffer(data, static_cast<size_t>(size)));
return do_write(*description, buffer, size);
}
}

8
Kernel/UserOrKernelBuffer.h
View file

@ -26,18 +26,18 @@ public:
return UserOrKernelBuffer(kernel_buffer);
}
static Optional<UserOrKernelBuffer> for_user_buffer(u8* user_buffer, size_t size)
static ErrorOr<UserOrKernelBuffer> for_user_buffer(u8* user_buffer, size_t size)
{
if (user_buffer && !Memory::is_user_range(VirtualAddress(user_buffer), size))
return {};
return Error::from_errno(EFAULT);
return UserOrKernelBuffer(user_buffer);
}
template<typename UserspaceType>
static Optional<UserOrKernelBuffer> for_user_buffer(UserspaceType userspace, size_t size)
static ErrorOr<UserOrKernelBuffer> for_user_buffer(UserspaceType userspace, size_t size)
{
if (!Memory::is_user_range(VirtualAddress(userspace.unsafe_userspace_ptr()), size))
return {};
return Error::from_errno(EFAULT);
return UserOrKernelBuffer(const_cast<u8*>((const u8*)userspace.unsafe_userspace_ptr()));
}