[lts88] net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg #310
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PlaidCat
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Jun 5, 2025
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do you know why there is a blank line in the headers?
commit a9c7531d71ab9dede879ca19b6eab24d3827a9b4 (HEAD -> bmastbergen_ciqlts8_8/VULN-6468, origin/bmastbergen_ciqlts8_8/VULN-6468)
Author: Brett Mastbergen <bmastbergen@ciq.com>
Date: Tue Jun 3 17:03:12 2025 +0000
net: sched: sch_qfq: prevent slab-out-of-bounds in qfq_activate_agg
jira VULN-6468
cve CVE-2023-31436
commit-author Gwangun Jung <exsociety@gmail.com>
commit 3037933448f60f9acb705997eae62013ecb81e0d
If the TCA_QFQ_LMAX value is not offered through nlattr, lmax is determined by the MTU value of the network device.
currently my scripts that work reading our header are looking for the first blank line to indicate that the original message is below this and to stop trying to parse.
I supposed we could forcibly insert a marker too in the future.
I really don't. That is weird. Will fix. |
jira VULN-6468 cve CVE-2023-31436 commit-author Gwangun Jung <exsociety@gmail.com> 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 <exsociety@gmail.com> Signed-off-by: Gwangun Jung <exsociety@gmail.com> Acked-by: Jamal Hadi Salim<jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net> (cherry picked from commit 3037933) Signed-off-by: Brett Mastbergen <bmastbergen@ciq.com>
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jira VULN-6468
cve CVE-2023-31436
Same as #308
Build log
Testing
kselftests were run before and after applying the fix
selftest-4.18.0-477.27.1.el8_8.88ciq_lts.5.2.x86_64.log
selftest-4.18.0-bmastbergen_ciqlts8_8_VULN-6468-a9c7531d71ab+.log