Zig 0.17.0-dev (Split by item)

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markSecret

timing_safe.markSecret

fn markSecret(ptr: anytype, comptime action: enum

File

lib/std/crypto/timing_safe.zig:134

Code

fn markSecret(ptr: anytype, comptime action: enum { classify, declassify }) void {
    const t = @typeInfo(@TypeOf(ptr));
    if (t != .pointer) @compileError("Pointer expected - Found: " ++ @typeName(@TypeOf(ptr)));
    const p = t.pointer;
    if (p.attrs.@"allowzero") @compileError("A nullable pointer is always assumed to leak information via side channels");
    const child = @typeInfo(p.child);

    switch (child) {
        .void, .null, .comptime_int, .comptime_float => return,
        .pointer => {
            if (child.pointer.size == .Slice) {
                @compileError("Found pointer to pointer. If the intent was to pass a slice, maybe remove the leading & in the function call");
            }
            @compileError("A pointer value is always assumed leak information via side channels");
        },
        else => {
            const mem8: *const [@sizeOf(@TypeOf(ptr.*))]u8 = @ptrCast(@constCast(ptr));
            if (action == .classify) {
                std.valgrind.memcheck.makeMemUndefined(mem8);
            } else {
                std.valgrind.memcheck.makeMemDefined(mem8);
            }
        },
    }
}