Description
In the Linux kernel, the following vulnerability has been resolved: net: fix use-after-free in tw_timer_handler A real world panic issue was found as follow in Linux 5.4. BUG: unable to handle page fault for address: ffffde49a863de28 PGD 7e6fe62067 P4D 7e6fe62067 PUD 7e6fe63067 PMD f51e064067 PTE 0 RIP: 0010:tw_timer_handler+0x20/0x40 Call Trace: call_timer_fn+0x2b/0x120 run_timer_softirq+0x1ef/0x450 __do_softirq+0x10d/0x2b8 irq_exit+0xc7/0xd0 smp_apic_timer_interrupt+0x68/0x120 apic_timer_interrupt+0xf/0x20 This issue was also reported since 2017 in the thread [1], unfortunately, the issue was still can be reproduced after fixing DCCP. The ipv4_mib_exit_net is called before tcp_sk_exit_batch when a net namespace is destroyed since tcp_sk_ops is registered befrore ipv4_mib_ops, which means tcp_sk_ops is in the front of ipv4_mib_ops in the list of pernet_list. There will be a use-after-free on net->mib.net_statistics in tw_timer_handler after ipv4_mib_exit_net if there are some inflight time-wait timers. This bug is not introduced by commit f2bf415cfed7 ("mib: add net to NET_ADD_STATS_BH") since the net_statistics is a global variable instead of dynamic allocation and freeing. Actually, commit 61a7e26028b9 ("mib: put net statistics on struct net") introduces the bug since it put net statistics on struct net and free it when net namespace is destroyed. Moving init_ipv4_mibs() to the front of tcp_init() to fix this bug and replace pr_crit() with panic() since continuing is meaningless when init_ipv4_mibs() fails. [1] https://groups.google.com/g/syzkaller/c/p1tn-_Kc6l4/m/smuL_FMAAgAJ?pli=1
Details
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| linux | — | 5.4.0-105.119 |
| linux-allwinner-5.19 | — | — |
| linux-aws | — | 5.4.0-1069.73 |
| linux-aws-5.0 | — | — |
| linux-aws-5.11 | — | — |
| linux-aws-5.13 | — | — |
| linux-aws-5.19 | — | — |
| linux-aws-5.3 | — | — |
| linux-aws-5.4 | — | 5.4.0-1069.73~18.04.1 |
| linux-aws-5.8 | — | — |
| linux-aws-6.2 | — | — |
| linux-aws-fips | — | — |
| linux-aws-hwe | — | 4.15.0-1124.133~16.04.1 |
| linux-azure | — | 5.4.0-1073.76 |
| linux-azure-4.15 | — | 4.15.0-1134.147 |
| linux-azure-5.11 | — | — |
| linux-azure-5.13 | — | — |
| linux-azure-5.19 | — | — |
| linux-azure-5.3 | — | — |
| linux-azure-5.4 | — | 5.4.0-1073.76~18.04.1 |
| linux-azure-5.8 | — | — |
| linux-azure-6.2 | — | — |
| linux-azure-edge | — | — |
| linux-azure-fde | — | — |
| linux-azure-fde-5.19 | — | — |
| linux-azure-fde-6.2 | — | — |
| linux-azure-fips | — | — |
| linux-bluefield | — | — |
| linux-fips | — | — |
| linux-gcp | — | 5.4.0-1068.72 |
| linux-gcp-4.15 | — | 4.15.0-1119.133 |
| linux-gcp-5.11 | — | — |
| linux-gcp-5.13 | — | — |
| linux-gcp-5.19 | — | — |
| linux-gcp-5.3 | — | — |
| linux-gcp-5.4 | — | 5.4.0-1068.72~18.04.1 |
| linux-gcp-5.8 | — | — |
| linux-gcp-6.2 | — | — |
| linux-gcp-fips | — | — |
| linux-gke | — | — |
| linux-gke-4.15 | — | — |
| linux-gke-5.15 | — | — |
| linux-gke-5.4 | — | — |
| linux-gkeop | — | 5.4.0-1037.38 |
| linux-gkeop-5.4 | — | — |
| linux-hwe | — | — |
| linux-hwe-5.11 | — | — |
| linux-hwe-5.13 | — | — |
| linux-hwe-5.19 | — | — |
| linux-hwe-5.4 | — | 5.4.0-105.119~18.04.1 |
| linux-hwe-5.8 | — | — |
| linux-hwe-6.2 | — | — |
| linux-hwe-edge | — | — |
| linux-ibm | — | 5.4.0-1018.20 |
| linux-ibm-5.4 | — | 5.4.0-1018.20~18.04.1 |
| linux-intel-5.13 | — | — |
| linux-intel-iot-realtime | — | — |
| linux-kvm | — | 5.4.0-1059.62 |
| linux-lowlatency-hwe-5.19 | — | — |
| linux-lowlatency-hwe-6.2 | — | — |
| linux-lts-xenial | — | 4.4.0-253.287~14.04.1 |
| linux-nvidia | — | — |
| linux-nvidia-6.2 | — | — |
| 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-oracle | — | 5.4.0-1067.72 |
| linux-oracle-5.0 | — | — |
| linux-oracle-5.11 | — | — |
| linux-oracle-5.13 | — | — |
| linux-oracle-5.3 | — | — |
| linux-oracle-5.4 | — | 5.4.0-1067.72~18.04.1 |
| linux-oracle-5.8 | — | — |
| linux-raspi | — | 5.4.0-1056.63 |
| linux-raspi-5.4 | — | 5.4.0-1056.63~18.04.1 |
| linux-raspi-realtime | — | — |
| linux-raspi2 | — | — |
| linux-realtime | — | — |
| linux-riscv | — | — |
| linux-riscv-5.11 | — | — |
| linux-riscv-5.19 | — | — |
| linux-riscv-5.8 | — | — |
| linux-starfive-5.19 | — | — |
| linux-starfive-6.2 | — | — |
References
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