Messages in this thread | | | Date | Thu, 28 Apr 2022 11:07:29 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH 04/22] firmware: arm_scmi: Validate BASE_DISCOVER_LIST_PROTOCOLS reply |
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On Wed, Mar 30, 2022 at 04:05:33PM +0100, Cristian Marussi wrote: > Do not blindly trust SCMI backend server reply about list of implemented > protocols, instead validate the reported length of the list of protocols > against the real payload size of the message reply. > > Fixes: b6f20ff8bd9 ("firmware: arm_scmi: add common infrastructure and support for base protocol") > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> > --- > drivers/firmware/arm_scmi/base.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/drivers/firmware/arm_scmi/base.c b/drivers/firmware/arm_scmi/base.c > index f279146f8110..c1165d1282ef 100644 > --- a/drivers/firmware/arm_scmi/base.c > +++ b/drivers/firmware/arm_scmi/base.c > @@ -189,6 +189,9 @@ scmi_base_implementation_list_get(const struct scmi_protocol_handle *ph, > list = t->rx.buf + sizeof(*num_ret); > > do { > + size_t real_list_sz; > + u32 calc_list_sz; > + > /* Set the number of protocols to be skipped/already read */ > *num_skip = cpu_to_le32(tot_num_ret); > > @@ -202,6 +205,24 @@ scmi_base_implementation_list_get(const struct scmi_protocol_handle *ph, > break; > } > > + if (t->rx.len < (sizeof(u32) * 2)) { > + dev_err(dev, "Truncated reply - rx.len:%zd\n", > + t->rx.len); > + ret = -EPROTO; > + break; > + } > + > + real_list_sz = t->rx.len - sizeof(u32); > + calc_list_sz = ((loop_num_ret / sizeof(u32)) + > + !!(loop_num_ret % sizeof(u32))) * sizeof(u32);
Any reason this can't be (loop_num_ret - 1) / sizeof(u32) + 1 ?
-- Regards, Sudeep
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