Message-ID: <2025061850-CVE-2022-50062-13da@gregkh>
Date: Wed, 18 Jun 2025 13:02:07 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50062: net: bgmac: Fix a BUG triggered by wrong bytes_compl

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

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

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

net: bgmac: Fix a BUG triggered by wrong bytes_compl

On one of our machines we got:

kernel BUG at lib/dynamic_queue_limits.c:27!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
CPU: 0 PID: 1166 Comm: irq/41-bgmac Tainted: G        W  O    4.14.275-rt132 #1
Hardware name: BRCM XGS iProc
task: ee3415c0 task.stack: ee32a000
PC is at dql_completed+0x168/0x178
LR is at bgmac_poll+0x18c/0x6d8
pc : [<c03b9430>]    lr : [<c04b5a18>]    psr: 800a0313
sp : ee32be14  ip : 000005ea  fp : 00000bd4
r10: ee558500  r9 : c0116298  r8 : 00000002
r7 : 00000000  r6 : ef128810  r5 : 01993267  r4 : 01993851
r3 : ee558000  r2 : 000070e1  r1 : 00000bd4  r0 : ee52c180
Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 12c5387d  Table: 8e88c04a  DAC: 00000051
Process irq/41-bgmac (pid: 1166, stack limit = 0xee32a210)
Stack: (0xee32be14 to 0xee32c000)
be00:                                              ee558520 ee52c100 ef128810
be20: 00000000 00000002 c0116298 c04b5a18 00000000 c0a0c8c4 c0951780 00000040
be40: c0701780 ee558500 ee55d520 ef05b340 ef6f9780 ee558520 00000001 00000040
be60: ffffe000 c0a56878 ef6fa040 c0952040 0000012c c0528744 ef6f97b0 fffcfb6a
be80: c0a04104 2eda8000 c0a0c4ec c0a0d368 ee32bf44 c0153534 ee32be98 ee32be98
bea0: ee32bea0 ee32bea0 ee32bea8 ee32bea8 00000000 c01462e4 ffffe000 ef6f22a8
bec0: ffffe000 00000008 ee32bee4 c0147430 ffffe000 c094a2a8 00000003 ffffe000
bee0: c0a54528 00208040 0000000c c0a0c8c4 c0a65980 c0124d3c 00000008 ee558520
bf00: c094a23c c0a02080 00000000 c07a9910 ef136970 ef136970 ee30a440 ef136900
bf20: ee30a440 00000001 ef136900 ee30a440 c016d990 00000000 c0108db0 c012500c
bf40: ef136900 c016da14 ee30a464 ffffe000 00000001 c016dd14 00000000 c016db28
bf60: ffffe000 ee21a080 ee30a400 00000000 ee32a000 ee30a440 c016dbfc ee25fd70
bf80: ee21a09c c013edcc ee32a000 ee30a400 c013ec7c 00000000 00000000 00000000
bfa0: 00000000 00000000 00000000 c0108470 00000000 00000000 00000000 00000000
bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
[<c03b9430>] (dql_completed) from [<c04b5a18>] (bgmac_poll+0x18c/0x6d8)
[<c04b5a18>] (bgmac_poll) from [<c0528744>] (net_rx_action+0x1c4/0x494)
[<c0528744>] (net_rx_action) from [<c0124d3c>] (do_current_softirqs+0x1ec/0x43c)
[<c0124d3c>] (do_current_softirqs) from [<c012500c>] (__local_bh_enable+0x80/0x98)
[<c012500c>] (__local_bh_enable) from [<c016da14>] (irq_forced_thread_fn+0x84/0x98)
[<c016da14>] (irq_forced_thread_fn) from [<c016dd14>] (irq_thread+0x118/0x1c0)
[<c016dd14>] (irq_thread) from [<c013edcc>] (kthread+0x150/0x158)
[<c013edcc>] (kthread) from [<c0108470>] (ret_from_fork+0x14/0x24)
Code: a83f15e0 0200001a 0630a0e1 c3ffffea (f201f0e7)

The issue seems similar to commit 90b3b339364c ("net: hisilicon: Fix a BUG
trigered by wrong bytes_compl") and potentially introduced by commit
b38c83dd0866 ("bgmac: simplify tx ring index handling").

If there is an RX interrupt between setting ring->end
and netdev_sent_queue() we can hit the BUG_ON as bgmac_dma_tx_free()
can miscalculate the queue size while called from bgmac_poll().

The machine which triggered the BUG runs a v4.14 RT kernel - but the issue
seems present in mainline too.

The Linux kernel CVE team has assigned CVE-2022-50062 to this issue.


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

	Issue introduced in 4.1 with commit b38c83dd08665a93e439c4ffd9eef31bc098a6ea and fixed in 5.4.211 with commit ac6d4482f29ab992b605c1b4bd1347f1f679f4e4
	Issue introduced in 4.1 with commit b38c83dd08665a93e439c4ffd9eef31bc098a6ea and fixed in 5.10.138 with commit ab2b55bb25db289ba0b68e3d58494476bdb1041d
	Issue introduced in 4.1 with commit b38c83dd08665a93e439c4ffd9eef31bc098a6ea and fixed in 5.15.63 with commit c506c9a97120f43257e9b3ce7b1f9a24eafc3787
	Issue introduced in 4.1 with commit b38c83dd08665a93e439c4ffd9eef31bc098a6ea and fixed in 5.19.4 with commit da1421a29d3b8681ba6a7f686bd0b40dda5acaf3
	Issue introduced in 4.1 with commit b38c83dd08665a93e439c4ffd9eef31bc098a6ea and fixed in 6.0 with commit 1b7680c6c1f6de9904f1d9b05c952f0c64a03350

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-2022-50062
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/ethernet/broadcom/bgmac.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/ac6d4482f29ab992b605c1b4bd1347f1f679f4e4
	https://git.kernel.org/stable/c/ab2b55bb25db289ba0b68e3d58494476bdb1041d
	https://git.kernel.org/stable/c/c506c9a97120f43257e9b3ce7b1f9a24eafc3787
	https://git.kernel.org/stable/c/da1421a29d3b8681ba6a7f686bd0b40dda5acaf3
	https://git.kernel.org/stable/c/1b7680c6c1f6de9904f1d9b05c952f0c64a03350

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