Re: [dpdk-dev] [PATCH] net/i40e: fix out of bounds read issue

[Ye Xiaolong <xiaolong.ye@intel.com>]

On 05/07, Di, ChenxuX wrote:
>Hi, xiaolong
>
>> -----Original Message-----
>> From: Ye, Xiaolong
>> Sent: Thursday, May 7, 2020 1:15 PM
>> To: Di, ChenxuX <chenxux.di@intel.com>
>> Cc: dev@dpdk.org; Xing, Beilei <beilei.xing@intel.com>
>> Subject: Re: [dpdk-dev] [PATCH] net/i40e: fix out of bounds read issue
>> 
>> On 05/07, Chenxu Di wrote:
>> >This patch fixes (out-of-bounds read) coverity issue.
>> >
>> >Coverity issue: 357699
>> >Coverity issue: 357694
>> >Fixes: feaae285b342 ("net/i40e: support hash configuration in RSS
>> >flow")
>> >
>> >Signed-off-by: Chenxu Di <chenxux.di@intel.com>
>> >---
>> > drivers/net/i40e/i40e_ethdev.c | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> >diff --git a/drivers/net/i40e/i40e_ethdev.c
>> >b/drivers/net/i40e/i40e_ethdev.c index 749d85f54..6c295ac5a 100644
>> >--- a/drivers/net/i40e/i40e_ethdev.c
>> >+++ b/drivers/net/i40e/i40e_ethdev.c
>> >@@ -13180,7 +13180,7 @@ i40e_rss_config_hash_function(struct i40e_pf *pf,
>> > 		}
>> >
>> > 		for (j = I40E_FILTER_PCTYPE_INVALID + 1;
>> >-		     j < I40E_FILTER_PCTYPE_MAX; j++) {
>> >+		     j < I40E_FILTER_PCTYPE_MAX && i < UINT64_BIT; j++) {
>> 
>> I see i is defined as uint32_t, why compare it to UINT64_BIT here?
>> And could you specify where is the out of bounds read before the fix?
>
>The UINT64_BIT is the define of 64. And i is just used as the index of pctypes_tbl[].
>And the code is just copy the function i40e_set_hash_filter_global_config(),
>So I don't why he use the define UINT64_BIT as the value 64.
>
>> 
>> > 			if (pf->adapter->pctypes_tbl[i] & (1ULL << j))
>
>the out of bounds read is the pctypes_tbl[i]. the above code is that :
>
>		for (i = RTE_ETH_FLOW_UNKNOWN + 1; i < UINT64_BIT; i++) {
>			if (mask0 & (1UL << i))
>				break;
>		}
>If the loop doesn't break; the value of i will be 64 while the length of pctypes_tbl[] is 64.

Got it, can you move the i < UINT64_BIT check before the new for loop, so it doesn't
need to check it everytime?

Thanks,
Xiaolong

>
>> > 				i40e_write_global_rx_ctl(hw,
>> > 					I40E_GLQF_HSYM(j),
>> >@@ -13312,7 +13312,7 @@ i40e_rss_clear_hash_function(struct i40e_pf *pf,
>> > 		}
>> >
>> > 		for (j = I40E_FILTER_PCTYPE_INVALID + 1;
>> >-		     j < I40E_FILTER_PCTYPE_MAX; j++) {
>> >+		     j < I40E_FILTER_PCTYPE_MAX && i < UINT64_BIT; j++) {
>> > 			if (pf->adapter->pctypes_tbl[i] & (1ULL << j))
>> > 				i40e_write_global_rx_ctl(hw,
>> > 					I40E_GLQF_HSYM(j),
>> >--
>> >2.17.1
>> >