发布于3月6日3月6日 Members SUSE: CVE-2021-47488: SUSE Linux Security Advisory Severity 4 CVSS (AV:L/AC:M/Au:N/C:P/I:P/A:P) Published 05/22/2024 Created 08/16/2024 Added 08/09/2024 Modified 08/09/2024 Description In the Linux kernel, the following vulnerability has been resolved: cgroup: Fix memory leak caused by missing cgroup_bpf_offline When enabling CONFIG_CGROUP_BPF, kmemleak can be observed by running the command as below: $mount -t cgroup -o none,name=foo cgroup cgroup/ $umount cgroup/ unreferenced object 0xc3585c40 (size 64): comm "mount", pid 425, jiffies 4294959825 (age 31.990s) hex dump (first 32 bytes): 01 00 00 80 84 8c 28 c0 00 00 00 00 00 00 00 00......(......... 00 00 00 00 00 00 00 00 6c 43 a0 c3 00 00 00 00........lC...... backtrace: [<e95a2f9e>] cgroup_bpf_inherit+0x44/0x24c [<1f03679c>] cgroup_setup_root+0x174/0x37c [<ed4b0ac5>] cgroup1_get_tree+0x2c0/0x4a0 [<f85b12fd>] vfs_get_tree+0x24/0x108 [<f55aec5c>] path_mount+0x384/0x988 [<e2d5e9cd>] do_mount+0x64/0x9c [<208c9cfe>] sys_mount+0xfc/0x1f4 [<06dd06e0>] ret_fast_syscall+0x0/0x48 [<a8308cb3>] 0xbeb4daa8 This is because that since the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") root_cgrp->bpf.refcnt.data is allocated by the function percpu_ref_init in cgroup_bpf_inherit which is called by cgroup_setup_root when mounting, but not freed along with root_cgrp when umounting. Adding cgroup_bpf_offline which calls percpu_ref_kill to cgroup_kill_sb can free root_cgrp->bpf.refcnt.data in umount path. This patch also fixes the commit 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself"). A cgroup_bpf_offline is needed to do a cleanup that frees the resources which are allocated by cgroup_bpf_inherit in cgroup_setup_root. And inside cgroup_bpf_offline, cgroup_get() is at the beginning and cgroup_put is at the end of cgroup_bpf_release which is called by cgroup_bpf_offline. So cgroup_bpf_offline can keep the balance of cgroup's refcount. 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 References https://attackerkb.com/topics/cve-2021-47488 CVE - 2021-47488
