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medium5.5

CVE-2024-26752

In the Linux kernel, the following vulnerability has been resolved: l2tp: pass correct message length to ip6_append_data l2tp_ip6_sendmsg needs to avoid accoun…

Impact

In the Linux kernel, the following vulnerability has been resolved: l2tp: pass correct message length to ip6_append_data l2tp_ip6_sendmsg needs to avoid accounting for the transport header twice when splicing more data into an already partially-occupied skbuff. To manage this, we check whether the skbuff contains data using skb_queue_empty when deciding how much data to append using ip6_append_data. However, the code which performed the calculation was incorrect: ulen = len + skb_queue_empty(&sk->sk_write_queue) ? transhdrlen : 0; ...due to C operator precedence, this ends up setting ulen to transhdrlen for messages with a non-zero length, which results in corrupted packets on the wire. Add parentheses to correct the calculation in line with the original intent.

Affected products

VendorProductAffected versions
LinuxLinux Kernel
from 4.19.296 before 4.19.308
from 5.4.258 before 5.4.270
from 5.10.198 before 5.10.211
from 5.15.135 before 5.15.150
from 6.1.57 before 6.1.80
from 6.6 before 6.6.19
DebianDebian Linux
Version 10.0

Weakness classification

CWE-131

References