Improper Input Validation Affecting kernel-debug-devel package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-debug-devel package and not the kernel-debug-devel package as distributed by RHEL. See How to fix? for RHEL:7 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