Improper Input Validation Affecting kernel-rt-debug package, versions <0:4.18.0-553.16.1.rt7.357.el8_10

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug package and not the kernel-rt-debug package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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)={&(0x7f0000ffb000/0x3000)=nil, 0x3000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, &(0x7f0000000440)=0x40) r6 = openat$dir(0xffffffffffffff9c, &(0x7f00000000c0)='./file0\x00', 0x181e42, 0x0)

• https://access.redhat.com/security/cve/CVE-2024-26640
• https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
• https://git.kernel.org/stable/c/1b8adcc0e2c584fec778add7777fe28e20781e60
• https://git.kernel.org/stable/c/577e4432f3ac810049cb7e6b71f4d96ec7c6e894
• https://git.kernel.org/stable/c/718f446e60316bf606946f7f42367d691d21541e
• https://git.kernel.org/stable/c/b383d4ea272fe5795877506dcce5aad1f6330e5e
• https://git.kernel.org/stable/c/d15cc0f66884ef2bed28c7ccbb11c102aa3a0760
• https://git.kernel.org/stable/c/f48bf9a83b1666d934247cb58a9887d7b3127b6f