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. > @@ -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? Cheers, Jeff
