Description
In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: unshare the skb before writing the control block bcmgenet stores first_cb, last_cb and bytes_sent in the skb control block and reads them back on completion to free the skb and credit BQL. ether_setup() leaves IFF_TX_SKB_SHARING set, so the stack can resubmit a shared skb that is still in the ring. The next transmit overwrites last_cb, so the earlier slots complete without crediting their bytes and BQL stalls the queue until the watchdog resets it. Unshare the skb before writing the control block. Reproduce with pktgen in clone_skb mode, which hands the driver the same skb while earlier copies are still in the ring: modprobe pktgen pg=/proc/net/pktgen echo "add_device eth0" > $pg/kpktgend_0 echo "dst_mac AA:BB:CC:DD:EE:FF" > $pg/eth0 echo "dst 192.0.2.1" > $pg/eth0 echo "clone_skb 8" > $pg/eth0 echo "count 0" > $pg/eth0 echo start > $pg/pgctrl & sleep 5 echo stop > $pg/pgctrl wait cat /sys/class/net/eth0/queues/tx-0/byte_queue_limits/inflight inflight stays nonzero on the now idle queue. clone_skb 0 leaves it at zero.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
f48bed16a756f5bc0244acd581f61968f7d7c2a4 to < 40c04abcbc34e3afe338f41dae851ecbd72852acaffectedf48bed16a756f5bc0244acd581f61968f7d7c2a4 to < 7939ad3b4db9eadf45a64f0524f38337a9494672affectedf48bed16a756f5bc0244acd581f61968f7d7c2a4 to < 89771ce4f8f67dcffae561b2ccac95c0f6e3aa01affectedfb4ca2b4bc6712a6ad635df5b9b41131846589f9affected3.16.50 to < 3.17affected
Linux Linux
Default version status: affected
4.13affected0 to < 4.13unaffected6.18.59 to ≤ 6.18.*unaffected7.2.13 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected