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Vulnerability CVE-2024-41066
Published: 2024-07-29
| Description: |
In the Linux kernel, the following vulnerability has been resolved:
ibmvnic: Add tx check to prevent skb leak
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. |
References: |
https://git.kernel.org/stable/c/16ad1557cae582e79bb82dddd612d9bdfaa11d4c
https://git.kernel.org/stable/c/267c61c4afed0ff9a2e83462abad3f41d8ca1f06
https://git.kernel.org/stable/c/e7b75def33eae61ddaad6cb616c517dc3882eb2a
https://git.kernel.org/stable/c/0983d288caf984de0202c66641577b739caad561
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