CVE-2024-26640

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

tcp: add sanity checks to rx zerocopy

TCP rx zerocopy intent is to map pages initially allocated

from NIC drivers, not pages owned by a fs.

This patch adds to can_map_frag() these additional checks:

- Page must not be a compound one.

- page->mapping must be NULL.

This fixes the panic reported by ZhangPeng.

syzbot was able to loopback packets built with sendfile(),

mapping pages owned by an ext4 file to TCP rx zerocopy.

r3 = socket$inet_tcp(0x2, 0x1, 0x0)

mmap(&(0x7f0000ff9000/0x4000)=nil, 0x4000, 0x0, 0x12, r3, 0x0)

r4 = socket$inet_tcp(0x2, 0x1, 0x0)

bind$inet(r4, &(0x7f0000000000)={0x2, 0x4e24, @multicast1}, 0x10)

connect$inet(r4, &(0x7f00000006c0)={0x2, 0x4e24, @empty}, 0x10)

r5 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00',

0x181e42, 0x0)

fallocate(r5, 0x0, 0x0, 0x85b8)

sendfile(r4, r5, 0x0, 0x8ba0)

getsockopt$inet_tcp_TCP_ZEROCOPY_RECEIVE(r4, 0x6, 0x23,

&(0x7f00000001c0)={&(0x7f00

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References