From 741690db7a357743545e0fa83310bdb1152ecaac Mon Sep 17 00:00:00 2001 From: Cristian Dumitrescu Date: Mon, 11 Jan 2021 18:11:38 +0000 Subject: [PATCH] i40e: fix potential NULL pointer dereferencing MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 7128c834d30e6b2cf649f14d8fc274941786d0e1 ] Currently, the function i40e_construct_skb_zc only frees the input xdp buffer when the output skb is successfully built. On error, the function i40e_clean_rx_irq_zc does not commit anything for the current packet descriptor and simply exits the packet descriptor processing loop, with the plan to restart the processing of this descriptor on the next invocation. Therefore, on error the ring next-to-clean pointer should not advance, the xdp i.e. *bi buffer should not be freed and the current buffer info should not be invalidated by setting *bi to NULL. Therefore, the *bi should only be set to NULL when the function i40e_construct_skb_zc is successful, otherwise a NULL *bi will be dereferenced when the work for the current descriptor is eventually restarted. Fixes: 3b4f0b66c2b3 ("i40e, xsk: Migrate to new MEM_TYPE_XSK_BUFF_POOL") Signed-off-by: Cristian Dumitrescu Acked-by: Björn Töpel Link: https://lore.kernel.org/r/20210111181138.49757-1-cristian.dumitrescu@intel.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/intel/i40e/i40e_xsk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index e402c62eb313..8557807b4171 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -348,12 +348,12 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget) * SBP is *not* set in PRT_SBPVSI (default not set). */ skb = i40e_construct_skb_zc(rx_ring, *bi); - *bi = NULL; if (!skb) { rx_ring->rx_stats.alloc_buff_failed++; break; } + *bi = NULL; cleaned_count++; i40e_inc_ntc(rx_ring); -- 2.17.1