In the Linux kernel, the following vulnerability has been resolved:
net_sched: fix NULL deref in fifo_set_limit()
syzbot reported another NULL deref in fifo_set_limit() [1]
I could repro the issue with :
unshare -n tc qd add dev lo root handle 1:0 tbf limit 200000 burst 70000 rate 100Mbit tc qd replace dev lo parent 1:0 pfifo_fast tc qd change dev lo root handle 1:0 tbf limit 300000 burst 70000 rate 100Mbit
pfifo_fast does not have a change() operation. Make fifo_set_limit() more robust about this.
[1] BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 1cf99067 P4D 1cf99067 PUD 7ca49067 PMD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 14443 Comm: syz-executor959 Not tainted 5.15.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc9000e2f7310 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffffffff8d6ecc00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff888024c27910 RDI: ffff888071e34000 RBP: ffff888071e34000 R08: 0000000000000001 R09: ffffffff8fcfb947 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888024c27910 R13: ffff888071e34018 R14: 0000000000000000 R15: ffff88801ef74800 FS: 00007f321d897700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000000722c3000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fifo_set_limit net/sched/sch_fifo.c:242 [inline] fifo_set_limit+0x198/0x210 net/sched/sch_fifo.c:227 tbf_change+0x6ec/0x16d0 net/sched/sch_tbf.c:418 qdisc_change net/sched/sch_api.c:1332 [inline] tc_modify_qdisc+0xd9a/0x1a60 net/sched/sch_api.c:1634 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-livepatch-5.10.75-79.358Upgrade python-perf-debuginfoUpgrade kernelUpgrade kernel-livepatch-4.14.252-195.481Upgrade perf-debuginfoUpgrade kernel-headersUpgrade python-perfUpgrade kernel-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-debuginfo-common-aarch64Upgrade kernel-tools-develUpgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade kernel-toolsUpgrade bpftoolUpgrade perf | May 21, 2025 | May 21, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | May 21, 2024 |
| Huawei Euleros 2_0_sp9 | — | Upgrade kernelUpgrade kernel-toolsUpgrade python3-perfUpgrade kernel-tools-libs | Oct 8, 2024 | May 21, 2024 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | May 21, 2024 |
| Suse | — | Upgrade kselftests-kmp-64kbUpgrade ocfs2-kmp-rtUpgrade cluster-md-kmp-defaultUpgrade gfs2-kmp-rtUpgrade kernel-azure-extraUpgrade kernel-sourceUpgrade kernel-azure-vdsoUpgrade kernel-64kb-optionalUpgrade kernel-default-extraUpgrade kernel-syms-rtUpgrade kernel-macrosUpgrade kernel-kvmsmallUpgrade kernel-64kb-develUpgrade gfs2-kmp-64kbUpgrade kernel-rt-develUpgrade kernel-64kbUpgrade kernel-zfcpdumpUpgrade dtb-exynosUpgrade kernel-azure-develUpgrade kernel-default-base-rebuildUpgrade dtb-marvellUpgrade kernel-kvmsmall-develUpgrade kernel-rtUpgrade dlm-kmp-azureUpgrade dtb-amlogicUpgrade dtb-amazonUpgrade kernel-default-vdsoUpgrade kernel-64kb-livepatch-develUpgrade kernel-azure-livepatch-develUpgrade kernel-debug-livepatch-develUpgrade kernel-devel-rtUpgrade dtb-hisiliconUpgrade kernel-syms-azureUpgrade kernel-devel-azureUpgrade kselftests-kmp-defaultUpgrade kernel-rt-livepatch-develUpgrade kernel-obs-qaUpgrade dlm-kmp-64kbUpgrade dtb-lgUpgrade cluster-md-kmp-azureUpgrade kernel-kvmsmall-livepatch-develUpgrade kernel-symsUpgrade kernel-default-develUpgrade dtb-mediatekUpgrade dtb-qcomUpgrade dtb-armUpgrade dtb-freescaleUpgrade kernel-default-livepatchUpgrade kernel-default-manUpgrade kernel-source-azureUpgrade dtb-apmUpgrade kernel-rt_debug-vdsoUpgrade kernel-azureUpgrade dtb-renesasUpgrade kernel-kvmsmall-vdsoUpgrade ocfs2-kmp-defaultUpgrade ocfs2-kmp-azureUpgrade kernel-docs-htmlUpgrade kernel-azure-optionalUpgrade dtb-xilinxUpgrade reiserfs-kmp-defaultUpgrade ocfs2-kmp-64kbUpgrade reiserfs-kmp-azureUpgrade kernel-develUpgrade dtb-appleUpgrade gfs2-kmp-azureUpgrade kernel-rt-extraUpgrade kernel-debug-develUpgrade kselftests-kmp-rtUpgrade reiserfs-kmp-rtUpgrade dtb-sprdUpgrade reiserfs-kmp-64kbUpgrade kernel-defaultUpgrade kernel-rt_debugUpgrade kernel-azure-baseUpgrade kernel-rt-livepatchUpgrade kernel-rt-vdsoUpgrade kernel-default-optionalUpgrade dtb-caviumUpgrade kernel-obs-buildUpgrade kernel-rt_debug-livepatch-develUpgrade kernel-docsUpgrade kernel-debugUpgrade dtb-broadcomUpgrade kernel-source-rtUpgrade kselftests-kmp-azureUpgrade dtb-rockchipUpgrade kernel-64kb-extraUpgrade kernel-debug-vdsoUpgrade dtb-amdUpgrade cluster-md-kmp-64kbUpgrade kernel-rt-optionalUpgrade kernel-default-livepatch-develUpgrade gfs2-kmp-defaultUpgrade dlm-kmp-rtUpgrade dtb-alteraUpgrade kernel-rt_debug-develUpgrade dlm-kmp-defaultUpgrade cluster-md-kmp-rtUpgrade kernel-default-baseUpgrade dtb-socionextUpgrade dtb-nvidiaUpgrade dtb-allwinnerUpgrade kernel-source-vanilla | Aug 9, 2024 | May 21, 2024 |
| Ubuntu | — | Upgrade linux-oracleUpgrade linux-azure-fipsUpgrade linux-gcp-fipsUpgrade linux-kvmUpgrade linux-gcp-5.4Upgrade linux-ibmUpgrade linux-gcp-4.15Upgrade linux-hweUpgrade linux-awsUpgrade linux-aws-fipsUpgrade linux-azure-4.15Upgrade linux-azure-5.4Upgrade linux-azureUpgrade linux-hwe-5.4Upgrade linux-gkeopUpgrade linux-raspiUpgrade linux-raspi-5.4Upgrade linux-oracle-5.4Upgrade linux-aws-hweUpgrade linux-bluefieldUpgrade linuxUpgrade linux-gcpUpgrade linux-fipsUpgrade linux-aws-5.4 | Nov 19, 2024 | May 21, 2024 |
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