linux-cve-announce - CVE-2025-37749: net: ppp: Add bound checking for skb data on ppp_sync

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025050136-CVE-2025-37749-0f49@gregkh>
Date: Thu,  1 May 2025 14:56:55 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-37749: net: ppp: Add bound checking for skb data on ppp_sync_txmung

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

net: ppp: Add bound checking for skb data on ppp_sync_txmung

Ensure we have enough data in linear buffer from skb before accessing
initial bytes. This prevents potential out-of-bounds accesses
when processing short packets.

When ppp_sync_txmung receives an incoming package with an empty
payload:
(remote) gef➤  p *(struct pppoe_hdr *) (skb->head + skb->network_header)
$18 = {
	type = 0x1,
	ver = 0x1,
	code = 0x0,
	sid = 0x2,
        length = 0x0,
	tag = 0xffff8880371cdb96
}

from the skb struct (trimmed)
      tail = 0x16,
      end = 0x140,
      head = 0xffff88803346f400 "4",
      data = 0xffff88803346f416 ":\377",
      truesize = 0x380,
      len = 0x0,
      data_len = 0x0,
      mac_len = 0xe,
      hdr_len = 0x0,

it is not safe to access data[2].

[pabeni@...hat.com: fixed subj typo]

The Linux kernel CVE team has assigned CVE-2025-37749 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.1.135 with commit b78f2b458f56a5a4d976c8e01c43dbf58d3ea2ca
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.88 with commit fbaffe8bccf148ece8ad67eb5d7aa852cabf59c8
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.24 with commit b4c836d33ca888695b2f2665f948bc1b34fbd533
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.13.12 with commit 1f6eb9fa87a781d5370c0de7794ae242f1a95ee5
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.14.3 with commit 6e8a6bf43cea4347121ab21bb1ed8d7bef7e732e
	Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.15-rc2 with commit aabc6596ffb377c4c9c8f335124b92ea282c9821

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-37749
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ppp/ppp_synctty.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/b78f2b458f56a5a4d976c8e01c43dbf58d3ea2ca
	https://git.kernel.org/stable/c/fbaffe8bccf148ece8ad67eb5d7aa852cabf59c8
	https://git.kernel.org/stable/c/b4c836d33ca888695b2f2665f948bc1b34fbd533
	https://git.kernel.org/stable/c/1f6eb9fa87a781d5370c0de7794ae242f1a95ee5
	https://git.kernel.org/stable/c/6e8a6bf43cea4347121ab21bb1ed8d7bef7e732e
	https://git.kernel.org/stable/c/aabc6596ffb377c4c9c8f335124b92ea282c9821