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SUSE: CVE-2021-46936: SUSE Linux Security Advisory

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SUSE: CVE-2021-46936: SUSE Linux Security Advisory

Severity
7
CVSS
(AV:L/AC:L/Au:S/C:C/I:C/A:C)
Published
02/27/2024
Created
08/16/2024
Added
08/09/2024
Modified
01/28/2025

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: <IRQ> 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

Solution(s)

  • suse-upgrade-cluster-md-kmp-64kb
  • suse-upgrade-cluster-md-kmp-azure
  • suse-upgrade-cluster-md-kmp-default
  • suse-upgrade-cluster-md-kmp-rt
  • suse-upgrade-dlm-kmp-64kb
  • suse-upgrade-dlm-kmp-azure
  • suse-upgrade-dlm-kmp-default
  • suse-upgrade-dlm-kmp-rt
  • suse-upgrade-dtb-allwinner
  • suse-upgrade-dtb-altera
  • suse-upgrade-dtb-amazon
  • suse-upgrade-dtb-amd
  • suse-upgrade-dtb-amlogic
  • suse-upgrade-dtb-apm
  • suse-upgrade-dtb-apple
  • suse-upgrade-dtb-arm
  • suse-upgrade-dtb-broadcom
  • suse-upgrade-dtb-cavium
  • suse-upgrade-dtb-exynos
  • suse-upgrade-dtb-freescale
  • suse-upgrade-dtb-hisilicon
  • suse-upgrade-dtb-lg
  • suse-upgrade-dtb-marvell
  • suse-upgrade-dtb-mediatek
  • suse-upgrade-dtb-nvidia
  • suse-upgrade-dtb-qcom
  • suse-upgrade-dtb-renesas
  • suse-upgrade-dtb-rockchip
  • suse-upgrade-dtb-socionext
  • suse-upgrade-dtb-sprd
  • suse-upgrade-dtb-xilinx
  • suse-upgrade-gfs2-kmp-64kb
  • suse-upgrade-gfs2-kmp-azure
  • suse-upgrade-gfs2-kmp-default
  • suse-upgrade-gfs2-kmp-rt
  • suse-upgrade-kernel-64kb
  • suse-upgrade-kernel-64kb-devel
  • suse-upgrade-kernel-64kb-extra
  • suse-upgrade-kernel-64kb-livepatch-devel
  • suse-upgrade-kernel-64kb-optional
  • suse-upgrade-kernel-azure
  • suse-upgrade-kernel-azure-devel
  • suse-upgrade-kernel-azure-extra
  • suse-upgrade-kernel-azure-livepatch-devel
  • suse-upgrade-kernel-azure-optional
  • suse-upgrade-kernel-azure-vdso
  • suse-upgrade-kernel-debug
  • suse-upgrade-kernel-debug-devel
  • suse-upgrade-kernel-debug-livepatch-devel
  • suse-upgrade-kernel-debug-vdso
  • suse-upgrade-kernel-default
  • suse-upgrade-kernel-default-base
  • suse-upgrade-kernel-default-base-rebuild
  • suse-upgrade-kernel-default-devel
  • suse-upgrade-kernel-default-extra
  • suse-upgrade-kernel-default-livepatch
  • suse-upgrade-kernel-default-livepatch-devel
  • suse-upgrade-kernel-default-optional
  • suse-upgrade-kernel-default-vdso
  • suse-upgrade-kernel-devel
  • suse-upgrade-kernel-devel-azure
  • suse-upgrade-kernel-devel-rt
  • suse-upgrade-kernel-docs
  • suse-upgrade-kernel-docs-html
  • suse-upgrade-kernel-kvmsmall
  • suse-upgrade-kernel-kvmsmall-devel
  • suse-upgrade-kernel-kvmsmall-livepatch-devel
  • suse-upgrade-kernel-kvmsmall-vdso
  • suse-upgrade-kernel-macros
  • suse-upgrade-kernel-obs-build
  • suse-upgrade-kernel-obs-qa
  • suse-upgrade-kernel-rt
  • suse-upgrade-kernel-rt-devel
  • suse-upgrade-kernel-rt-extra
  • suse-upgrade-kernel-rt-livepatch
  • suse-upgrade-kernel-rt-livepatch-devel
  • suse-upgrade-kernel-rt-optional
  • suse-upgrade-kernel-rt-vdso
  • suse-upgrade-kernel-rt_debug
  • suse-upgrade-kernel-rt_debug-devel
  • suse-upgrade-kernel-rt_debug-livepatch-devel
  • suse-upgrade-kernel-rt_debug-vdso
  • suse-upgrade-kernel-source
  • suse-upgrade-kernel-source-azure
  • suse-upgrade-kernel-source-rt
  • suse-upgrade-kernel-source-vanilla
  • suse-upgrade-kernel-syms
  • suse-upgrade-kernel-syms-azure
  • suse-upgrade-kernel-syms-rt
  • suse-upgrade-kernel-zfcpdump
  • suse-upgrade-kselftests-kmp-64kb
  • suse-upgrade-kselftests-kmp-azure
  • suse-upgrade-kselftests-kmp-default
  • suse-upgrade-kselftests-kmp-rt
  • suse-upgrade-ocfs2-kmp-64kb
  • suse-upgrade-ocfs2-kmp-azure
  • suse-upgrade-ocfs2-kmp-default
  • suse-upgrade-ocfs2-kmp-rt
  • suse-upgrade-reiserfs-kmp-64kb
  • suse-upgrade-reiserfs-kmp-azure
  • suse-upgrade-reiserfs-kmp-default
  • suse-upgrade-reiserfs-kmp-rt

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