Messages in this thread | | | Date | Thu, 28 Sep 2023 19:53:14 -0700 | From | Joao Moreira <> | Subject | Re: [PATCH v3 1/2] Make loop indexes unsigned |
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On 2023-09-28 06:40, Pablo Neira Ayuso wrote: > On Wed, Sep 27, 2023 at 09:47:14AM -0700, joao@overdrivepizza.com > wrote: >> From: Joao Moreira <joao.moreira@intel.com> >> >> Both flow_rule_alloc and offload_action_alloc functions received an >> unsigned num_actions parameters which are then operated within a loop. >> The index of this loop is declared as a signed int. If it was possible >> to pass a large enough num_actions to these functions, it would lead >> to >> an out of bounds write. >> >> After checking with maintainers, it was mentioned that front-end will >> cap the num_actions value and that it is not possible to reach this >> function with such a large number. Yet, for correctness, it is still >> better to fix this. >> >> This issue was observed by the commit author while reviewing a >> write-up >> regarding a CVE within the same subsystem [1]. >> >> 1 - https://nickgregory.me/post/2022/03/12/cve-2022-25636/ >> >> Signed-off-by: Joao Moreira <joao.moreira@intel.com> >> --- >> net/core/flow_offload.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c >> index bc5169482710..bc3f53a09d8f 100644 >> --- a/net/core/flow_offload.c >> +++ b/net/core/flow_offload.c >> @@ -10,7 +10,7 @@ >> struct flow_rule *flow_rule_alloc(unsigned int num_actions) >> { >> struct flow_rule *rule; >> - int i; >> + unsigned int i; > > With the 2^8 cap, I don't think this patch is required anymore.
Hm. While I understand that there is not a significant menace haunting this... would it be good for (1) type correctness and (2) prevent that things blow up if something changes and someone misses this spot?
> >> >> rule = kzalloc(struct_size(rule, action.entries, num_actions), >> GFP_KERNEL); >> @@ -31,7 +31,7 @@ EXPORT_SYMBOL(flow_rule_alloc); >> struct flow_offload_action *offload_action_alloc(unsigned int >> num_actions) >> { >> struct flow_offload_action *fl_action; >> - int i; >> + unsigned int i; >> >> fl_action = kzalloc(struct_size(fl_action, action.entries, >> num_actions), >> GFP_KERNEL); >> -- >> 2.42.0 >>
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