Daniel Samson
8d4a7cf240
A new user-memory module owns every kernel touch of a user buffer: copyFromUser, the new copyToUser, and the resolve behind both. The walk accumulates the U/S and writable bits down all four levels with the MMU's own AND rule — folding a 2 MiB leaf in before it resolves and refusing a 1 GiB leaf outright — so a copy honours what ring 3 itself would be allowed, closing the presence-only trust model the IPC layer carried since bring-up. It then confirms the frame is physmap-backed, because that is how the copy reaches it: an mmio_map'd BAR passes the permission walk and would otherwise fault ring 0 on an alias the physmap never mapped, on the IPC path as much as the new one. The nine stragglers that dereferenced user pointers raw now route through it, so a bad pointer returns -EFAULT where it used to fault the kernel. The write direction restructures its callees around kernel bounce buffers: scheduler and devices-broker enumerate from a slot cursor (a task exiting between chunks can neither duplicate nor lose an entry), klog_read drains the ring in chunks, and fs_node stages headers and names contiguously. fs_resolve copies out before installing the endpoint handle, so a faulting copy cannot strand a capability; its out-capacity bound no longer adds an unbounded ring-3 length to the base, which wrapped and trapped the kernel's own overflow check. debug_write reads the caller's message once. Suite 107/107 (new user-memory case: seven bad pointers refused, each paired with a sound call that must still succeed).
16 lines
597 B
Zig
16 lines
597 B
Zig
//! The user-memory-test fixture as a binary package (docs/build-packages-plan.md):
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//! this file names the binary and EXACTLY the modules its source imports —
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//! build-support resolves each name from the domains this zon declares.
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const std = @import("std");
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const build_support = @import("build-support");
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pub fn build(b: *std.Build) void {
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const exe = build_support.userBinary(b, .{
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.name = "user-memory-test",
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.root_source_file = b.path("user-memory-test.zig"),
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.imports = &.{ "abi", "system-call", "logging", "driver" },
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});
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b.installArtifact(exe);
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}
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