On 10/25/25 18:58, Kohei Enju wrote:
There are off-by-one bugs when configuring RSS hash key and lookup table, causing out-of-bounds reads to memory [1] and out-of-bounds writes to device registers.Before commit 43a3d9ba34c9 ("i40evf: Allow PF driver to configure RSS"), the loop upper bounds were: i <= I40E_VFQF_{HKEY,HLUT}_MAX_INDEX which is safe since the value is the last valid index. That commit changed the bounds to: i <= adapter->rss_{key,lut}_size / 4 where `rss_{key,lut}_size / 4` is the number of dwords, so the last valid index is `(rss_{key,lut}_size / 4) - 1`. Therefore, using `<=` accesses one element past the end. Fix the issues by using `<` instead of `<=`, ensuring we do not exceed the bounds. [1] KASAN splat about rss_key_size off-by-one BUG: KASAN: slab-out-of-bounds in iavf_config_rss+0x619/0x800 Read of size 4 at addr ffff888102c50134 by task kworker/u8:6/63
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Fixes: 43a3d9ba34c9 ("i40evf: Allow PF driver to configure RSS") Signed-off-by: Kohei Enju <[email protected]> --- drivers/net/ethernet/intel/iavf/iavf_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c index c2fbe443ef85..4b0fc8f354bc 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_main.c +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c @@ -1726,11 +1726,11 @@ static int iavf_config_rss_reg(struct iavf_adapter *adapter) u16 i;dw = (u32 *)adapter->rss_key;- for (i = 0; i <= adapter->rss_key_size / 4; i++) + for (i = 0; i < adapter->rss_key_size / 4; i++) wr32(hw, IAVF_VFQF_HKEY(i), dw[i]);dw = (u32 *)adapter->rss_lut;- for (i = 0; i <= adapter->rss_lut_size / 4; i++) + for (i = 0; i < adapter->rss_lut_size / 4; i++) wr32(hw, IAVF_VFQF_HLUT(i), dw[i]);
this is generally the last defined register mapping, so I get why KASAN is able to report a violation here (I assume that we map "just enough") impressive, and thanks for the fix! Reviewed-by: Przemek Kitszel <[email protected]>
iavf_flush(hw);
