Commit 226f3b25 authored by Nick Child's avatar Nick Child Committed by Dong Chenchen
Browse files

ibmvnic: Add tx check to prevent skb leak 

mainline inclusion
from mainline-v6.10-rc6
commit 0983d288caf984de0202c66641577b739caad561
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEMC
CVE: CVE-2024-41066

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0983d288caf984de0202c66641577b739caad561



--------------------------------

Below is a summary of how the driver stores a reference to an skb during
transmit:
    tx_buff[free_map[consumer_index]]->skb = new_skb;
    free_map[consumer_index] = IBMVNIC_INVALID_MAP;
    consumer_index ++;
Where variable data looks like this:
    free_map == [4, IBMVNIC_INVALID_MAP, IBMVNIC_INVALID_MAP, 0, 3]
                                               	consumer_index^
    tx_buff == [skb=null, skb=<ptr>, skb=<ptr>, skb=null, skb=null]

The driver has checks to ensure that free_map[consumer_index] pointed to
a valid index but there was no check to ensure that this index pointed
to an unused/null skb address. So, if, by some chance, our free_map and
tx_buff lists become out of sync then we were previously risking an
skb memory leak. This could then cause tcp congestion control to stop
sending packets, eventually leading to ETIMEDOUT.

Therefore, add a conditional to ensure that the skb address is null. If
not then warn the user (because this is still a bug that should be
patched) and free the old pointer to prevent memleak/tcp problems.

Signed-off-by: default avatarNick Child <nnac123@linux.ibm.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Conflicts:
	drivers/net/ethernet/ibm/ibmvnic.c
[commit 8880fc66 rename local variable index to bufidx, which
not merged lead to conflicts.]
Signed-off-by: default avatarDong Chenchen <dongchenchen2@huawei.com>
parent e6bd197e

drivers/net/ethernet/ibm/ibmvnic.c

+12 −0
Original line number Diff line number Diff line
@@ -1625,6 +1625,18 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) 
	    (tx_pool->consumer_index + 1) % tx_pool->num_buffers;



	tx_buff = &tx_pool->tx_buff[index];



	/* Sanity checks on our free map to make sure it points to an index

	 * that is not being occupied by another skb. If skb memory is

	 * not freed then we see congestion control kick in and halt tx.

	 */

	if (unlikely(tx_buff->skb)) {

		dev_warn_ratelimited(dev, "TX free map points to untracked skb (%s %d idx=%d)\n",

				     skb_is_gso(skb) ? "tso_pool" : "tx_pool",

				     queue_num, index);

		dev_kfree_skb_any(tx_buff->skb);

	}



	tx_buff->skb = skb;

	tx_buff->data_dma[0] = data_dma_addr;

	tx_buff->data_len[0] = skb->len;