From: Vinicius Costa Gomes vinicius.gomes@intel.com

mainline inclusion from mainline-v5.14-rc2 commit 7b292608db23ccbbfbfa50cdb155d01725d7a52e category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4I4 CVE: CVE-2021-47301

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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Cleans the next descriptor to watch (next_to_watch) when cleaning the TX ring.

Failure to do so can cause invalid memory accesses. If igb_poll() runs while the controller is reset this can lead to the driver try to free a skb that was already freed.

(The crash is harder to reproduce with the igb driver, but the same potential problem exists as the code is identical to igc)

Fixes: 7cc6fd4c60f2 ("igb: Don't bother clearing Tx buffer_info in igb_clean_tx_ring") Signed-off-by: Vinicius Costa Gomes vinicius.gomes@intel.com Reported-by: Erez Geva erez.geva.ext@siemens.com Tested-by: Tony Brelinski tonyx.brelinski@intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: dengquan dengquan9@huawei.com --- drivers/net/ethernet/intel/igb/igb_main.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 6d9b8e81b44d..e54f1c033c60 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -4684,6 +4684,8 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring) DMA_TO_DEVICE); }

+ tx_buffer->next_to_watch = NULL; + /* move us one more past the eop_desc for start of next pkt */ tx_buffer++; i++;