On Tue, Jan 15, 2019 at 12:39 PM Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > > Dan Williams <dan.j.williams@xxxxxxxxx> writes: > > > On Tue, Jan 15, 2019 at 6:16 AM Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > >> > >> Dan Williams <dan.j.williams@xxxxxxxxx> writes: > >> > >> > Changes since v1 [1]: > >> > * Include another patch make sure that function-number zero can be > >> > safely used as an invalid function number (Jeff) > >> > * Add a comment clarifying why zero is an invalid function number (Jeff) > >> > * Pass nfit_mem to cmd_to_func() (Jeff) > >> > * Collect a Tested-by from Sujith > >> > [1]: https://lists.01.org/pipermail/linux-nvdimm/2019-January/019435.html > >> > >> For the series: > >> > >> Reviewed-by: Jeff Moyer <jmoyer@xxxxxxxxxx> > >> > >> Thanks, Dan! > > > > Thanks, although I just realized one more change. The ND_CMD_CALL case > > should zero out command after the function translation, otherwise > > userspace can call functions that the kernel is blocking in the > > dsm_mask. > > > > Holler if this invalidates your "Reviewed-by". > > AAAAAAAHHHHHHHHHH!!!! > > :) > > > diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c > > index 87e02f281e51..d7747aceb7ab 100644 > > --- a/drivers/acpi/nfit/core.c > > +++ b/drivers/acpi/nfit/core.c > > @@ -463,6 +463,12 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor > > *nd_desc, struct nvdimm *nvdimm, > > func = cmd_to_func(nfit_mem, cmd, buf); > > if (func < 0) > > return func; > > + /* > > + * In the ND_CMD_CALL case we're now dependent on 'func' > > + * being validated by the dimm's dsm_mask > > + */ > > + if (cmd == ND_CMD_CALL) > > + cmd = 0; > > dimm_name = nvdimm_name(nvdimm); > > cmd_name = nvdimm_cmd_name(cmd); > > cmd_mask = nvdimm_cmd_mask(nvdimm); > dsm_mask = nfit_mem->dsm_mask; > desc = nd_cmd_dimm_desc(cmd); > > That sure doesn't look right. Now cmd_name and desc will be wrong. Ah, whoops, yes good catch. Guess this shows there is not good ND_CMD_CALL coverage in the unit tests... > > > @@ -477,8 +483,10 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor > > *nd_desc, struct nvdimm *nvdimm, > > cmd_name = nvdimm_bus_cmd_name(cmd); > > cmd_mask = nd_desc->cmd_mask; > > dsm_mask = cmd_mask; > > - if (cmd == ND_CMD_CALL) > > + if (cmd == ND_CMD_CALL) { > > dsm_mask = nd_desc->bus_dsm_mask; > > + cmd = 0; > > + } > > desc = nd_cmd_bus_desc(cmd); > > And again here. > > We could reorder the zeroing, or you could modify the check for a valid > comand/function. Something like this? > > /* > * Check for a valid command. For ND_CMD_CALL, we also > * have to make sure that the DSM function is supported. > */ > if (cmd == ND_CMD_CALL && !test_bit(func, &dsm_mask)) > return -ENOTTY; > else if (!test_bit(cmd, &cmd_mask)) > return -ENOTTY; > > Which way do you think is cleaner? Modifying the check looks cleaner. Thanks for hollering!
