On Thu, Aug 31, 2023 at 06:28:00PM -0700, Jakub Kicinski wrote: > On Thu, 31 Aug 2023 18:04:35 -0700 joao@xxxxxxxxxxxxxxxxxx wrote: > > The function flow_rule_alloc in net/core/flow_offload.c [2] gets an > > unsigned int num_actions (line 10) and later traverses the actions in > > the rule (line 24) setting hw.stats to FLOW_ACTION_HW_STATS_DONT_CARE. > > > > Within the same file, the loop in the line 24 compares a signed int > > (i) to an unsigned int (num_actions), and then uses i as an array > > index. If an integer overflow happens, then the array within the loop > > is wrongly indexed, causing a write out of bounds. > > > > After checking with maintainers, it seems that the front-end caps the > > maximum value of num_action, thus it is not possible to reach the given > > write out of bounds, yet, still, to prevent disasters it is better to > > fix the signedness here. > > How did you find this? The commit messages should include info > about how the issue was discovered. This is net-next material IMO, none of the existing interfaces uses such a large number of actions for this to be an issue.
