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Filename Latest commit message Latest commit date
Pedro Tammela cf8ecd6ea6 net/sched: sch_qfq: account for stab overhead in qfq_enqueue
commit 3e337087c3b5805fe0b8a46ba622a962880b5d64 upstream.

Lion says:
-------
In the QFQ scheduler a similar issue to CVE-2023-31436
persists.

Consider the following code in net/sched/sch_qfq.c:

static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
                struct sk_buff **to_free)
{
     unsigned int len = qdisc_pkt_len(skb), gso_segs;

    // ...

     if (unlikely(cl->agg->lmax < len)) {
         pr_debug("qfq: increasing maxpkt from %u to %u for class %u",
              cl->agg->lmax, len, cl->common.classid);
         err = qfq_change_agg(sch, cl, cl->agg->class_weight, len);
         if (err) {
             cl->qstats.drops++;
             return qdisc_drop(skb, sch, to_free);
         }

    // ...

     }

Similarly to CVE-2023-31436, "lmax" is increased without any bounds
checks according to the packet length "len". Usually this would not
impose a problem because packet sizes are naturally limited.

This is however not the actual packet length, rather the
"qdisc_pkt_len(skb)" which might apply size transformations according to
"struct qdisc_size_table" as created by "qdisc_get_stab()" in
net/sched/sch_api.c if the TCA_STAB option was set when modifying the qdisc.

A user may choose virtually any size using such a table.

As a result the same issue as in CVE-2023-31436 can occur, allowing heap
out-of-bounds read / writes in the kmalloc-8192 cache.
-------

We can create the issue with the following commands:

tc qdisc add dev $DEV root handle 1: stab mtu 2048 tsize 512 mpu 0 \
overhead 999999999 linklayer ethernet qfq
tc class add dev $DEV parent 1: classid 1:1 htb rate 6mbit burst 15k
tc filter add dev $DEV parent 1: matchall classid 1:1
ping -I $DEV 1.1.1.2

This is caused by incorrectly assuming that qdisc_pkt_len() returns a
length within the QFQ_MIN_LMAX < len < QFQ_MAX_LMAX.

Fixes: 462dbc9101 ("pkt_sched: QFQ Plus: fair-queueing service at DRR cost")
Reported-by: Lion <nnamrec@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Shaoying Xu <shaoyi@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-11 11:53:54 +02:00
arch x86: fix backwards merge of GDS/SRSO bit 2023-08-08 19:56:37 +02:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-06-21 15:44:08 +02:00
Documentation Documentation: security-bugs.rst: clarify CVE handling 2023-08-11 11:53:52 +02:00
drivers cpufreq: intel_pstate: Drop ACPI _PSS states table patching 2023-08-11 11:53:53 +02:00
fs btrfs: fix race between quota disable and quota assign ioctls 2023-08-11 11:53:54 +02:00
include block: Fix a source code comment in include/uapi/linux/blkzoned.h 2023-08-11 11:53:49 +02:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:56:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel tracing: Fix warning in trace_buffered_event_disable() 2023-08-11 11:53:50 +02:00
lib debugobjects: Recheck debug_objects_enabled before reporting 2023-07-27 08:37:41 +02:00
LICENSES
mm mm: make wait_on_page_writeback() wait for multiple pending writebacks 2023-06-28 10:18:42 +02:00
net net/sched: sch_qfq: account for stab overhead in qfq_enqueue 2023-08-11 11:53:54 +02:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts modpost: fix off by one in is_executable_section() 2023-07-27 08:37:18 +02:00
security keys: Fix linking a duplicate key to a keyring's assoc_array 2023-08-11 11:53:47 +02:00
sound ASoC: wm8904: Fill the cache for WM8904_ADC_TEST_0 register 2023-08-11 11:53:53 +02:00
tools x86/bugs: Increase the x86 bugs vector size to two u32s 2023-08-08 19:56:37 +02:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Remove DECnet support from kernel 2023-06-21 15:44:10 +02:00
Makefile Linux 5.4.252 2023-08-08 19:56:37 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.