On 1/23/19 11:54 AM, Borislav Petkov wrote:
On Tue, Jan 22, 2019 at 04:09:12PM +0000, Ross Lagerwall wrote:
When checking a generic status block, we iterate over all the generic
data blocks. The loop condition only checks that the start of the
generic data block is valid (within estatus->data_length) but not the
whole block. Because the size of data blocks (excluding error data) may
vary depending on the revision and the revision is contained within the
data block, ensure that enough of the current data block is valid before
dereferencing any members otherwise an OOB access may occur if
snip
- data_len -= acpi_hest_get_record_size(gdata);
+ record_len = acpi_hest_get_record_size(gdata);
record_size so that it matches the function name it is used to compute
this.
Btw, trying to grok this code is making my head spin.
+ if (record_len > data_len)
+ return -EINVAL;
<---- newline here.
Btw, those checks in the loop you can abstract away into a separate
function so that you end up with something more readable like:
apei_estatus_for_each_section(estatus, gdata) {
record_size = check_hest_record_size(gdata, data_len);
if (!record_size)
return -EINVAL;
data_len -= record_size;
}
for example.
There are only two if statements in the loop body -- I don't think it is
necessary to abstract this into a separate function (which still
requires having one if statement in the loop body).
I've made the other changes you suggested and sent a V2.
Thanks,
--
Ross Lagerwall
