Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Address reentrant enqueue adding class to eltree twice Savino says: "We are writing to report that this recent patch (141d34391abbb315d68556b7c67ad97885407547) [1] can be bypassed, and a UAF can still occur when HFSC is utilized with NETEM. The patch only checks the cl->cl_nactive field to determine whether it is the first insertion or not [2], but this field is only incremented by init_vf [3]. By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the check and insert the class twice in the eltree. Under normal conditions, this would lead to an infinite loop in hfsc_dequeue for the reasons we already explained in this report [5]. However, if TBF is added as root qdisc and it is configured with a very low rate, it can be utilized to prevent packets from being dequeued. This behavior can be exploited to perform subsequent insertions in the HFSC eltree and cause a UAF." To fix both the UAF and the infinite loop, with netem as an hfsc child, check explicitly in hfsc_enqueue whether the class is already in the eltree whenever the HFSC_RSC flag is set. [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547 [2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572 [3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677 [4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574 [5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u
Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| linux | — | 6.8.0-63.66 |
| linux-allwinner-5.19 | — | — |
| linux-aws | — | 6.8.0-1031.33 |
| linux-aws-5.0 | — | — |
| linux-aws-5.11 | — | — |
| linux-aws-5.13 | — | — |
| linux-aws-5.15 | — | 5.15.0-1087.94~20.04.1 |
| linux-aws-5.19 | — | — |
| linux-aws-5.3 | — | — |
| linux-aws-5.4 | — | 5.4.0-1148.158~18.04.1 |
| linux-aws-5.8 | — | — |
| linux-aws-6.14 | — | 6.14.0-1009.9~24.04.1 |
| linux-aws-6.2 | — | — |
| linux-aws-6.5 | — | — |
| linux-aws-6.8 | — | 6.8.0-1031.33~22.04.1 |
| linux-aws-fips | — | 5.15.0-1087.94+fips1 |
| linux-azure | — | 6.8.0-1031.36 |
| linux-azure-5.11 | — | — |
| linux-azure-5.13 | — | — |
| linux-azure-5.15 | — | 5.15.0-1094.103~20.04.1 |
| linux-azure-5.19 | — | — |
| linux-azure-5.3 | — | — |
| linux-azure-5.4 | — | 5.4.0-1153.160~18.04.1 |
| linux-azure-5.8 | — | — |
| linux-azure-6.11 | — | 6.11.0-1018.18~24.04.1 |
| linux-azure-6.2 | — | — |
| linux-azure-6.5 | — | — |
| linux-azure-6.8 | — | 6.8.0-1031.36~22.04.1 |
| linux-azure-edge | — | — |
| linux-azure-fde | — | — |
| linux-azure-fde-5.19 | — | — |
| linux-azure-fde-6.17 | — | — |
| linux-azure-fde-6.2 | — | — |
| linux-azure-fips | — | 5.15.0-1094.103+fips1 |
| linux-azure-nvidia | — | 6.8.0-1019.20 |
| linux-bluefield | — | — |
| linux-fips | — | 6.8.0-78.78+fips1 |
| linux-gcp | — | 6.8.0-1032.34 |
| linux-gcp-5.11 | — | — |
| linux-gcp-5.13 | — | — |
| linux-gcp-5.15 | — | 5.15.0-1086.95~20.04.1 |
| linux-gcp-5.19 | — | — |
| linux-gcp-5.3 | — | — |
| linux-gcp-5.4 | — | 5.4.0-1151.160~18.04.1 |
| linux-gcp-5.8 | — | — |
| linux-gcp-6.11 | — | 6.11.0-1017.17~24.04.1 |
| linux-gcp-6.14 | — | 6.14.0-1011.11~24.04.1 |
| linux-gcp-6.2 | — | — |
| linux-gcp-6.5 | — | — |
| linux-gcp-6.8 | — | 6.8.0-1032.34~22.04.1 |
| linux-gcp-fips | — | 5.15.0-1086.95+fips1 |
| linux-gke | — | 6.8.0-1027.31 |
| linux-gke-4.15 | — | — |
| linux-gke-5.15 | — | — |
| linux-gke-5.4 | — | — |
| linux-gkeop | — | 6.8.0-1014.16 |
| linux-gkeop-5.15 | — | — |
| linux-gkeop-5.4 | — | — |
| linux-hwe | — | — |
| linux-hwe-5.11 | — | — |
| linux-hwe-5.13 | — | — |
| linux-hwe-5.15 | — | 5.15.0-143.153~20.04.1 |
| linux-hwe-5.19 | — | — |
| linux-hwe-5.4 | — | 5.4.0-219.239~18.04.1 |
| linux-hwe-5.8 | — | — |
| linux-hwe-6.11 | — | 6.11.0-29.29~24.04.1 |
| linux-hwe-6.2 | — | — |
| linux-hwe-6.5 | — | — |
| linux-hwe-6.8 | — | 6.8.0-64.67~22.04.1 |
| linux-hwe-edge | — | — |
| linux-ibm | — | 6.8.0-1028.28 |
| linux-ibm-5.15 | — | 5.15.0-1079.82~20.04.1 |
| linux-ibm-5.4 | — | 5.4.0-1094.99~18.04.1 |
| linux-ibm-6.8 | — | 6.8.0-1028.28~22.04.1 |
| linux-intel-5.13 | — | — |
| linux-intel-iot-realtime | — | 5.15.0-1080.82 |
| linux-intel-iotg | — | 5.15.0-1082.88 |
| linux-intel-iotg-5.15 | — | 5.15.0-1083.89~20.04.1 |
| linux-iot | — | 5.4.0-1052.55 |
| linux-kvm | — | 5.15.0-1083.88 |
| linux-lowlatency | — | 6.8.0-63.66.1 |
| linux-lowlatency-hwe-5.15 | — | 5.15.0-143.153~20.04.1 |
| linux-lowlatency-hwe-5.19 | — | — |
| linux-lowlatency-hwe-6.11 | — | 6.11.0-1016.17~24.04.1 |
| linux-lowlatency-hwe-6.2 | — | — |
| linux-lowlatency-hwe-6.5 | — | — |
| linux-lowlatency-hwe-6.8 | — | 6.8.0-63.66.1~22.04.1 |
| linux-nvidia | — | 6.8.0-1030.33 |
| linux-nvidia-6.11 | — | 6.11.0-1012.12 |
| linux-nvidia-6.2 | — | — |
| linux-nvidia-6.5 | — | — |
| linux-nvidia-6.8 | — | 6.8.0-1030.33~22.04.1 |
| linux-nvidia-lowlatency | — | 6.8.0-1030.33.1 |
| linux-nvidia-tegra | — | 6.8.0-1008.8 |
| linux-nvidia-tegra-5.15 | — | 5.15.0-1040.40~20.04.1 |
| linux-nvidia-tegra-igx | — | 5.15.0-1029.29 |
| linux-oem | — | — |
| linux-oem-5.10 | — | — |
| linux-oem-5.13 | — | — |
| linux-oem-5.14 | — | — |
| linux-oem-5.17 | — | — |
| linux-oem-5.6 | — | — |
| linux-oem-6.0 | — | — |
| linux-oem-6.1 | — | — |
| linux-oem-6.11 | — | 6.11.0-1025.25 |
| linux-oem-6.14 | — | 6.14.0-1006.6 |
| linux-oem-6.5 | — | — |
| linux-oem-6.8 | — | 6.8.0-1030.30 |
| linux-oracle | — | 6.8.0-1028.29 |
| linux-oracle-5.0 | — | — |
| linux-oracle-5.11 | — | — |
| linux-oracle-5.13 | — | — |
| linux-oracle-5.15 | — | 5.15.0-1084.90~20.04.1 |
| linux-oracle-5.3 | — | — |
| linux-oracle-5.4 | — | 5.4.0-1146.156~18.04.1 |
| linux-oracle-5.8 | — | — |
| linux-oracle-6.14 | — | 6.14.0-1009.9~24.04.1 |
| linux-oracle-6.5 | — | — |
| linux-oracle-6.8 | — | 6.8.0-1028.29~22.04.1 |
| linux-raspi | — | 6.8.0-1030.34 |
| linux-raspi-5.4 | — | 5.4.0-1131.144~18.04.1 |
| linux-raspi-realtime | — | 6.8.0-2025.26 |
| linux-raspi2 | — | — |
| linux-realtime | — | 6.8.1-1024.25 |
| linux-realtime-6.14 | — | 6.14.0-1010.10~24.04.1 |
| linux-realtime-6.8 | — | 6.8.1-1024.25~22.04.1 |
| linux-riscv | — | — |
| linux-riscv-5.11 | — | — |
| linux-riscv-5.15 | — | 5.15.0-1082.86~20.04.1 |
| linux-riscv-5.19 | — | — |
| linux-riscv-5.8 | — | — |
| linux-riscv-6.14 | — | 6.14.0-23.23.1~24.04.1 |
| linux-riscv-6.5 | — | — |
| linux-riscv-6.8 | — | 6.8.0-63.66~22.04.1 |
| linux-starfive-5.19 | — | — |
| linux-starfive-6.2 | — | — |
| linux-starfive-6.5 | — | — |
| linux-xilinx | — | 6.8.0-1017.18 |
| linux-xilinx-zynqmp | — | 5.15.0-1051.55 |
References
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