• Eric Holk's avatar
    [wasm] always allocate memory when guard regions are needed · d31dff84
    Eric Holk authored
    When using trap handlers, memory references do not get any checks inserted. This
    means there is no check for a null memory as happens when the memory size is
    0. Normally this would be correctly caught as an out of bounds access, since the
    low memory addresses are not normally mapped. However, if they were mapped for
    some reason, we would not catch the out of bounds access.
    
    The fix is to ensure WebAssembly instances always have a guard region even if
    the memory is size 0.
    
    This is a rewrite of 5e76ff5a
    
    Note that this can lead to a large amount of unnecessary address space usage,
    so we share a single reservation for empty array buffers.
    
    Bug: chromium:769637
    
    Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
    Change-Id: Ia8e84be6d595e347d3d342959f2c374db1a3f683
    Reviewed-on: https://chromium-review.googlesource.com/702657Reviewed-by: 's avatarDeepti Gandluri <gdeepti@chromium.org>
    Reviewed-by: 's avatarMichael Lippautz <mlippautz@chromium.org>
    Reviewed-by: 's avatarClemens Hammacher <clemensh@chromium.org>
    Commit-Queue: Eric Holk <eholk@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#52163}
    d31dff84
runtime-test.cc 34.6 KB