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SubjectRe: [PATCH v1] qlcnic: prevent ->dcb use-after-free on qlcnic_dcb_enable() failure
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On 12/20/22 4:32 PM, Michal Swiatkowski wrote:
> On Tue, Dec 20, 2022 at 03:56:49PM +0300, Daniil Tatianin wrote:
>> adapter->dcb would get silently freed inside qlcnic_dcb_enable() in
>> case qlcnic_dcb_attach() would return an error, which always happens
>> under OOM conditions. This would lead to use-after-free because both
>> of the existing callers invoke qlcnic_dcb_get_info() on the obtained
>> pointer, which is potentially freed at that point.
>>
>> Propagate errors from qlcnic_dcb_enable(), and instead free the dcb
>> pointer at callsite.
>>
>> Found by Linux Verification Center (linuxtesting.org) with the SVACE
>> static analysis tool.
>>
>> Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
>
> Please add Fix tag and net as target (net-next is close till the end of
> this year)
>
Sorry, I'll include a fixes tag.
Could you please explain what I would have to do to add net as target?
>> ---
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c | 9 ++++++++-
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h | 5 ++---
>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c | 9 ++++++++-
>> 3 files changed, 18 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
>> index dbb800769cb6..465f149d94d4 100644
>> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
>> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_83xx_init.c
>> @@ -2505,7 +2505,14 @@ int qlcnic_83xx_init(struct qlcnic_adapter *adapter)
>> goto disable_mbx_intr;
>>
>> qlcnic_83xx_clear_function_resources(adapter);
>> - qlcnic_dcb_enable(adapter->dcb);
>> +
>> + err = qlcnic_dcb_enable(adapter->dcb);
>> + if (err) {
>> + qlcnic_clear_dcb_ops(adapter->dcb);
>> + adapter->dcb = NULL;
>> + goto disable_mbx_intr;
>> + }
>
> Maybe I miss sth but it looks like there can be memory leak.
> For example if error in attach happen after allocating of dcb->cfg.
> Isn't it better to call qlcnic_dcb_free instead of qlcnic_clear_dcb_ops?
I think you're right, if attach fails midway then we might leak cfg or
something else.
I'll use qlcnic_dcb_free() instead and completely remove
qlcnic_clear_dcb_ops() as it
seems to be unused and relies on dcb being in a very specific state.
>> +
>> qlcnic_83xx_initialize_nic(adapter, 1);
>> qlcnic_dcb_get_info(adapter->dcb);
>>
>> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
>> index 7519773eaca6..e1460f9c38bf 100644
>> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
>> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_dcb.h
>> @@ -112,9 +112,8 @@ static inline void qlcnic_dcb_init_dcbnl_ops(struct qlcnic_dcb *dcb)
>> dcb->ops->init_dcbnl_ops(dcb);
>> }
>>
>> -static inline void qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
>> +static inline int qlcnic_dcb_enable(struct qlcnic_dcb *dcb)
>> {
>> - if (dcb && qlcnic_dcb_attach(dcb))
>> - qlcnic_clear_dcb_ops(dcb);
>> + return dcb ? qlcnic_dcb_attach(dcb) : 0;
>> }
>> #endif
>> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
>> index 28476b982bab..36ba15fc9776 100644
>> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
>> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c
>> @@ -2599,7 +2599,14 @@ qlcnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>> "Device does not support MSI interrupts\n");
>>
>> if (qlcnic_82xx_check(adapter)) {
>> - qlcnic_dcb_enable(adapter->dcb);
>> + err = qlcnic_dcb_enable(adapter->dcb);
>> + if (err) {
>> + qlcnic_clear_dcb_ops(adapter->dcb);
>> + adapter->dcb = NULL;
>> + dev_err(&pdev->dev, "Failed to enable DCB\n");
>> + goto err_out_free_hw;
>> + }
>> +
>> qlcnic_dcb_get_info(adapter->dcb);
>> err = qlcnic_setup_intr(adapter);
>>
>> --
>> 2.25.1
>>

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