[fips-legacy-8] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #295

bmastbergen · 2025-05-27T18:58:57Z

jira VULN-8813
cve CVE-2023-31436

commit-author Gwangun Jung <[email protected]>
commit 3037933448f60f9acb705997eae62013ecb81e0d

If the TCA_QFQ_LMAX value is not offered through nlattr, lmax is determined by the MTU value of the network device. The MTU of the loopback device can be set up to 2^31-1. As a result, it is possible to have an lmax value that exceeds QFQ_MIN_LMAX.

Due to the invalid lmax value, an index is generated that exceeds the QFQ_MAX_INDEX(=24) value, causing out-of-bounds read/write errors.

The following reports a oob access:

[   84.582666] BUG: KASAN: slab-out-of-bounds in qfq_activate_agg.constprop.0 (net/sched/sch_qfq.c:1027 net/sched/sch_qfq.c:1060 net/sched/sch_qfq.c:1313)
[   84.583267] Read of size 4 at addr ffff88810f676948 by task ping/301
[   84.583686]
[   84.583797] CPU: 3 PID: 301 Comm: ping Not tainted 6.3.0-rc5 #1
[   84.584164] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[   84.584644] Call Trace:
[   84.584787]  <TASK>
[   84.584906] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1))
[   84.585108] print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)
[   84.585570] kasan_report (mm/kasan/report.c:538)
[   84.585988] qfq_activate_agg.constprop.0 (net/sched/sch_qfq.c:1027 net/sched/sch_qfq.c:1060 net/sched/sch_qfq.c:1313)
[   84.586599] qfq_enqueue (net/sched/sch_qfq.c:1255)
[   84.587607] dev_qdisc_enqueue (net/core/dev.c:3776)
[   84.587749] __dev_queue_xmit (./include/net/sch_generic.h:186 net/core/dev.c:3865 net/core/dev.c:4212)
[   84.588763] ip_finish_output2 (./include/net/neighbour.h:546 net/ipv4/ip_output.c:228)
[   84.589460] ip_output (net/ipv4/ip_output.c:430)
[   84.590132] ip_push_pending_frames (./include/net/dst.h:444 net/ipv4/ip_output.c:126 net/ipv4/ip_output.c:1586 net/ipv4/ip_output.c:1606)
[   84.590285] raw_sendmsg (net/ipv4/raw.c:649)
[   84.591960] sock_sendmsg (net/socket.c:724 net/socket.c:747)
[   84.592084] __sys_sendto (net/socket.c:2142)
[   84.593306] __x64_sys_sendto (net/socket.c:2150)
[   84.593779] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
[   84.593902] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
[   84.594070] RIP: 0033:0x7fe568032066
[   84.594192] Code: 0e 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 41 89 ca 64 8b 04 25 18 00 00 00 85 c09[ 84.594796] RSP: 002b:00007ffce388b4e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c

Code starting with the faulting instruction
===========================================
[   84.595047] RAX: ffffffffffffffda RBX: 00007ffce388cc70 RCX: 00007fe568032066
[   84.595281] RDX: 0000000000000040 RSI: 00005605fdad6d10 RDI: 0000000000000003
[   84.595515] RBP: 00005605fdad6d10 R08: 00007ffce388eeec R09: 0000000000000010
[   84.595749] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040
[   84.595984] R13: 00007ffce388cc30 R14: 00007ffce388b4f0 R15: 0000001d00000001
[   84.596218]  </TASK>
[   84.596295]
[   84.596351] Allocated by task 291:
[   84.596467] kasan_save_stack (mm/kasan/common.c:46)
[   84.596597] kasan_set_track (mm/kasan/common.c:52)
[   84.596725] __kasan_kmalloc (mm/kasan/common.c:384)
[   84.596852] __kmalloc_node (./include/linux/kasan.h:196 mm/slab_common.c:967 mm/slab_common.c:974)
[   84.596979] qdisc_alloc (./include/linux/slab.h:610 ./include/linux/slab.h:731 net/sched/sch_generic.c:938)
[   84.597100] qdisc_create (net/sched/sch_api.c:1244)
[   84.597222] tc_modify_qdisc (net/sched/sch_api.c:1680)
[   84.597357] rtnetlink_rcv_msg (net/core/rtnetlink.c:6174)
[   84.597495] netlink_rcv_skb (net/netlink/af_netlink.c:2574)
[   84.597627] netlink_unicast (net/netlink/af_netlink.c:1340 net/netlink/af_netlink.c:1365)
[   84.597759] netlink_sendmsg (net/netlink/af_netlink.c:1942)
[   84.597891] sock_sendmsg (net/socket.c:724 net/socket.c:747)
[   84.598016] ____sys_sendmsg (net/socket.c:2501)
[   84.598147] ___sys_sendmsg (net/socket.c:2557)
[   84.598275] __sys_sendmsg (./include/linux/file.h:31 net/socket.c:2586)
[   84.598399] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
[   84.598520] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
[   84.598688]
[   84.598744] The buggy address belongs to the object at ffff88810f674000
[   84.598744]  which belongs to the cache kmalloc-8k of size 8192
[   84.599135] The buggy address is located 2664 bytes to the right of
[   84.599135]  allocated 7904-byte region [ffff88810f674000, ffff88810f675ee0)
[   84.599544]
[   84.599598] The buggy address belongs to the physical page:
[   84.599777] page:00000000e638567f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10f670
[   84.600074] head:00000000e638567f order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[   84.600330] flags: 0x200000000010200(slab|head|node=0|zone=2)
[   84.600517] raw: 0200000000010200 ffff888100043180 dead000000000122 0000000000000000
[   84.600764] raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
[   84.601009] page dumped because: kasan: bad access detected
[   84.601187]
[   84.601241] Memory state around the buggy address:
[   84.601396]  ffff88810f676800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   84.601620]  ffff88810f676880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   84.601845] >ffff88810f676900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   84.602069]                                               ^
[   84.602243]  ffff88810f676980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   84.602468]  ffff88810f676a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[   84.602693] ==================================================================
[   84.602924] Disabling lock debugging due to kernel taint

Fixes: 3015f3d2a3cd ("pkt_sched: enable QFQ to support TSO/GSO")
	Reported-by: Gwangun Jung <[email protected]>
	Signed-off-by: Gwangun Jung <[email protected]>
	Acked-by: Jamal Hadi Salim<[email protected]>
	Signed-off-by: David S. Miller <[email protected]>
(cherry picked from commit 3037933448f60f9acb705997eae62013ecb81e0d)
	Signed-off-by: Brett Mastbergen <[email protected]>

Build Log

/home/brett/kernel-src-tree
  CLEAN   arch/x86/tools
  CLEAN   scripts/basic
  CLEAN   scripts/kconfig
  CLEAN   scripts
  CLEAN   usr/include include/generated arch/x86/include/generated
  CLEAN   .config .config.old
[TIMER]{MRPROPER}: 13s
x86_64 architecture detected, copying config
'configs/kernel-x86_64.config' -> '.config'
Setting Local Version for build
CONFIG_LOCALVERSION="-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739"
Making olddefconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  YACC    scripts/kconfig/zconf.tab.c
  LEX     scripts/kconfig/zconf.lex.c
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
scripts/kconfig/conf  --olddefconfig Kconfig
#
# configuration written to .config
#
Starting Build
scripts/kconfig/conf  --syncconfig Kconfig
  SYSTBL  arch/x86/include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_32_ia32.h
  SYSHDR  arch/x86/include/generated/asm/unistd_64_x32.h
  SYSTBL  arch/x86/include/generated/asm/syscalls_64.h
  HYPERCALLS arch/x86/include/generated/asm/xen-hypercalls.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_x32.h
  SYSHDR  arch/x86/include/generated/uapi/asm/unistd_64.h
  HOSTCC  scripts/basic/bin2c
  WRAP    arch/x86/include/generated/uapi/asm/bpf_perf_event.h
  WRAP    arch/x86/include/generated/uapi/asm/poll.h
  WRAP    arch/x86/include/generated/uapi/asm/socket.h
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  DESCEND objtool
  DESCEND bpf/resolve_btfids
  MKDIR     /home/brett/kernel-src-tree/tools/bpf/resolve_btfids//libbpf
  MKDIR     /home/brett/kernel-src-tree/tools/bpf/resolve_btfids//libsubcmd
  HOSTCC  /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/fixdep.o
  HOSTCC  /home/brett/kernel-src-tree/tools/objtool/fixdep.o
  GEN     /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/libbpf/bpf_helper_defs.h
  HOSTLD  /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/fixdep-in.o
  LINK    /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/fixdep
  HOSTLD  /home/brett/kernel-src-tree/tools/objtool/fixdep-in.o
  LINK    /home/brett/kernel-src-tree/tools/objtool/fixdep
  CC      /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/main.o
  CC      /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/rbtree.o
  CC      /home/brett/kernel-src-tree/tools/bpf/resolve_btfids/zalloc.o
  CC      /home/brett/kernel-src-tree/tools/objtool/builtin-check.o

[SNIP]

  INSTALL sound/synth/snd-util-mem.ko
  INSTALL sound/usb/6fire/snd-usb-6fire.ko
  INSTALL sound/usb/bcd2000/snd-bcd2000.ko
  INSTALL sound/usb/caiaq/snd-usb-caiaq.ko
  INSTALL sound/usb/hiface/snd-usb-hiface.ko
  INSTALL sound/usb/line6/snd-usb-line6.ko
  INSTALL sound/usb/line6/snd-usb-pod.ko
  INSTALL sound/usb/line6/snd-usb-podhd.ko
  INSTALL sound/usb/line6/snd-usb-toneport.ko
  INSTALL sound/usb/line6/snd-usb-variax.ko
  INSTALL sound/usb/misc/snd-ua101.ko
  INSTALL sound/usb/snd-usb-audio.ko
  INSTALL sound/usb/snd-usbmidi-lib.ko
  INSTALL sound/usb/usx2y/snd-usb-us122l.ko
  INSTALL sound/usb/usx2y/snd-usb-usx2y.ko
  INSTALL sound/virtio/virtio_snd.ko
  INSTALL sound/x86/snd-hdmi-lpe-audio.ko
  INSTALL sound/xen/snd_xen_front.ko
  INSTALL virt/lib/irqbypass.ko
  DEPMOD  4.18.0-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739+
[TIMER]{MODULES}: 13s
Making Install
sh ./arch/x86/boot/install.sh 4.18.0-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739+ arch/x86/boot/bzImage \
	System.map "/boot"
[TIMER]{INSTALL}: 59s
Checking kABI
Checking kABI
kABI check passed
Setting Default Kernel to /boot/vmlinuz-4.18.0-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739+ and Index to 1
Hopefully Grub2.0 took everything ... rebooting after time metrices
[TIMER]{MRPROPER}: 13s
[TIMER]{BUILD}: 988s
[TIMER]{MODULES}: 13s
[TIMER]{INSTALL}: 59s
[TIMER]{TOTAL} 1089s
Rebooting in 10 seconds

Testing

kselftests were run before and after applying the fix

selftest-4.18.0-425.13.1.el8.ciqfipscompliant.39.1.x86_64.log

selftest-4.18.0-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739+.log

brett@lycia ~/ciq/vuln-8813 % grep ^ok selftest-4.18.0-425.13.1.el8.ciqfipscompliant.39.1.x86_64.log | wc -l
230
brett@lycia ~/ciq/vuln-8813 % grep ^ok selftest-4.18.0-b_f-l-8-c_4.18.0-425.13.1_VULN-8813-54888ce52739+.log | wc -l
230
brett@lycia ~/ciq/vuln-8813 %

jira VULN-8813 cve CVE-2023-31436 commit-author Gwangun Jung <[email protected]> commit 3037933 If the TCA_QFQ_LMAX value is not offered through nlattr, lmax is determined by the MTU value of the network device. The MTU of the loopback device can be set up to 2^31-1. As a result, it is possible to have an lmax value that exceeds QFQ_MIN_LMAX. Due to the invalid lmax value, an index is generated that exceeds the QFQ_MAX_INDEX(=24) value, causing out-of-bounds read/write errors. The following reports a oob access: [ 84.582666] BUG: KASAN: slab-out-of-bounds in qfq_activate_agg.constprop.0 (net/sched/sch_qfq.c:1027 net/sched/sch_qfq.c:1060 net/sched/sch_qfq.c:1313) [ 84.583267] Read of size 4 at addr ffff88810f676948 by task ping/301 [ 84.583686] [ 84.583797] CPU: 3 PID: 301 Comm: ping Not tainted 6.3.0-rc5 #1 [ 84.584164] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 [ 84.584644] Call Trace: [ 84.584787] <TASK> [ 84.584906] dump_stack_lvl (lib/dump_stack.c:107 (discriminator 1)) [ 84.585108] print_report (mm/kasan/report.c:320 mm/kasan/report.c:430) [ 84.585570] kasan_report (mm/kasan/report.c:538) [ 84.585988] qfq_activate_agg.constprop.0 (net/sched/sch_qfq.c:1027 net/sched/sch_qfq.c:1060 net/sched/sch_qfq.c:1313) [ 84.586599] qfq_enqueue (net/sched/sch_qfq.c:1255) [ 84.587607] dev_qdisc_enqueue (net/core/dev.c:3776) [ 84.587749] __dev_queue_xmit (./include/net/sch_generic.h:186 net/core/dev.c:3865 net/core/dev.c:4212) [ 84.588763] ip_finish_output2 (./include/net/neighbour.h:546 net/ipv4/ip_output.c:228) [ 84.589460] ip_output (net/ipv4/ip_output.c:430) [ 84.590132] ip_push_pending_frames (./include/net/dst.h:444 net/ipv4/ip_output.c:126 net/ipv4/ip_output.c:1586 net/ipv4/ip_output.c:1606) [ 84.590285] raw_sendmsg (net/ipv4/raw.c:649) [ 84.591960] sock_sendmsg (net/socket.c:724 net/socket.c:747) [ 84.592084] __sys_sendto (net/socket.c:2142) [ 84.593306] __x64_sys_sendto (net/socket.c:2150) [ 84.593779] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) [ 84.593902] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) [ 84.594070] RIP: 0033:0x7fe568032066 [ 84.594192] Code: 0e 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 41 89 ca 64 8b 04 25 18 00 00 00 85 c09[ 84.594796] RSP: 002b:00007ffce388b4e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c Code starting with the faulting instruction =========================================== [ 84.595047] RAX: ffffffffffffffda RBX: 00007ffce388cc70 RCX: 00007fe568032066 [ 84.595281] RDX: 0000000000000040 RSI: 00005605fdad6d10 RDI: 0000000000000003 [ 84.595515] RBP: 00005605fdad6d10 R08: 00007ffce388eeec R09: 0000000000000010 [ 84.595749] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040 [ 84.595984] R13: 00007ffce388cc30 R14: 00007ffce388b4f0 R15: 0000001d00000001 [ 84.596218] </TASK> [ 84.596295] [ 84.596351] Allocated by task 291: [ 84.596467] kasan_save_stack (mm/kasan/common.c:46) [ 84.596597] kasan_set_track (mm/kasan/common.c:52) [ 84.596725] __kasan_kmalloc (mm/kasan/common.c:384) [ 84.596852] __kmalloc_node (./include/linux/kasan.h:196 mm/slab_common.c:967 mm/slab_common.c:974) [ 84.596979] qdisc_alloc (./include/linux/slab.h:610 ./include/linux/slab.h:731 net/sched/sch_generic.c:938) [ 84.597100] qdisc_create (net/sched/sch_api.c:1244) [ 84.597222] tc_modify_qdisc (net/sched/sch_api.c:1680) [ 84.597357] rtnetlink_rcv_msg (net/core/rtnetlink.c:6174) [ 84.597495] netlink_rcv_skb (net/netlink/af_netlink.c:2574) [ 84.597627] netlink_unicast (net/netlink/af_netlink.c:1340 net/netlink/af_netlink.c:1365) [ 84.597759] netlink_sendmsg (net/netlink/af_netlink.c:1942) [ 84.597891] sock_sendmsg (net/socket.c:724 net/socket.c:747) [ 84.598016] ____sys_sendmsg (net/socket.c:2501) [ 84.598147] ___sys_sendmsg (net/socket.c:2557) [ 84.598275] __sys_sendmsg (./include/linux/file.h:31 net/socket.c:2586) [ 84.598399] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) [ 84.598520] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) [ 84.598688] [ 84.598744] The buggy address belongs to the object at ffff88810f674000 [ 84.598744] which belongs to the cache kmalloc-8k of size 8192 [ 84.599135] The buggy address is located 2664 bytes to the right of [ 84.599135] allocated 7904-byte region [ffff88810f674000, ffff88810f675ee0) [ 84.599544] [ 84.599598] The buggy address belongs to the physical page: [ 84.599777] page:00000000e638567f refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10f670 [ 84.600074] head:00000000e638567f order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 [ 84.600330] flags: 0x200000000010200(slab|head|node=0|zone=2) [ 84.600517] raw: 0200000000010200 ffff888100043180 dead000000000122 0000000000000000 [ 84.600764] raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000 [ 84.601009] page dumped because: kasan: bad access detected [ 84.601187] [ 84.601241] Memory state around the buggy address: [ 84.601396] ffff88810f676800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 84.601620] ffff88810f676880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 84.601845] >ffff88810f676900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 84.602069] ^ [ 84.602243] ffff88810f676980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 84.602468] ffff88810f676a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 84.602693] ================================================================== [ 84.602924] Disabling lock debugging due to kernel taint Fixes: 3015f3d ("pkt_sched: enable QFQ to support TSO/GSO") Reported-by: Gwangun Jung <[email protected]> Signed-off-by: Gwangun Jung <[email protected]> Acked-by: Jamal Hadi Salim<[email protected]> Signed-off-by: David S. Miller <[email protected]> (cherry picked from commit 3037933) Signed-off-by: Brett Mastbergen <[email protected]>

bmastbergen requested review from kerneltoast, PlaidCat and thefossguy-ciq May 27, 2025 18:58

jdieter approved these changes May 29, 2025

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kerneltoast approved these changes May 30, 2025

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bmastbergen merged commit 17b8ca5 into fips-legacy-8-compliant/4.18.0-425.13.1 May 30, 2025
1 check passed

bmastbergen mentioned this pull request Jun 4, 2025

[lts92] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #308

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bmastbergen deleted the bmastbergen_fips-legacy-8-compliant/4.18.0-425.13.1/VULN-8813 branch June 24, 2025 02:41

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[fips-legacy-8] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #295

[fips-legacy-8] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #295

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[fips-legacy-8] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #295

[fips-legacy-8] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #295

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bmastbergen commented May 27, 2025

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