CVE-2021-47082 (GCVE-0-2021-47082)
Vulnerability from cvelistv5
Published
2024-03-04 18:06
Modified
2026-08-05 08:45
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: tun: avoid double free in tun_free_netdev Avoid double free in tun_free_netdev() by moving the dev->tstats and tun->security allocs to a new ndo_init routine (tun_net_init()) that will be called by register_netdevice(). ndo_init is paired with the desctructor (tun_free_netdev()), so if there's an error in register_netdevice() the destructor will handle the frees. BUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 CPU: 0 PID: 25750 Comm: syz-executor416 Not tainted 5.16.0-rc2-syzk #1 Hardware name: Red Hat KVM, BIOS Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106 print_address_description.constprop.9+0x28/0x160 mm/kasan/report.c:247 kasan_report_invalid_free+0x55/0x80 mm/kasan/report.c:372 ____kasan_slab_free mm/kasan/common.c:346 [inline] __kasan_slab_free+0x107/0x120 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook mm/slub.c:1749 [inline] slab_free mm/slub.c:3513 [inline] kfree+0xac/0x2d0 mm/slub.c:4561 selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 security_tun_dev_free_security+0x4f/0x90 security/security.c:2342 tun_free_netdev+0xe6/0x150 drivers/net/tun.c:2215 netdev_run_todo+0x4df/0x840 net/core/dev.c:10627 rtnl_unlock+0x13/0x20 net/core/rtnetlink.c:112 __tun_chr_ioctl+0x80c/0x2870 drivers/net/tun.c:3302 tun_chr_ioctl+0x2f/0x40 drivers/net/tun.c:3311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
References
Impacted products
Vendor Product Version
Linux Linux Version: 662ca437e714caaab855b12415d6ffd815985bc0
Version: 662ca437e714caaab855b12415d6ffd815985bc0
Version: 662ca437e714caaab855b12415d6ffd815985bc0
Version: 662ca437e714caaab855b12415d6ffd815985bc0
Version: 662ca437e714caaab855b12415d6ffd815985bc0
Version: a81a02460bdf054ca0c60c5aed29941f7134092d
Version: 6fc265f7a86d81e052508d03da555188f5882c3e
Version: 3.10.16   ≤
Version: 3.11.5   ≤
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\"https://git.kernel.org/stable/c/a01a4e9f5dc93335c716fa4023b1901956e8c904\"}, {\"url\": \"https://git.kernel.org/stable/c/3cb5ae77799e8ed6ec3fec0b6b4cd07f01650cc5\"}, {\"url\": \"https://git.kernel.org/stable/c/158b515f703e75e7d68289bf4d98c664e1d632df\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\ntun: avoid double free in tun_free_netdev\\n\\nAvoid double free in tun_free_netdev() by moving the\\ndev-\u003etstats and tun-\u003esecurity allocs to a new ndo_init routine\\n(tun_net_init()) that will be called by register_netdevice().\\nndo_init is paired with the desctructor (tun_free_netdev()),\\nso if there\u0027s an error in register_netdevice() the destructor\\nwill handle the frees.\\n\\nBUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605\\n\\nCPU: 0 PID: 25750 Comm: syz-executor416 Not tainted 5.16.0-rc2-syzk #1\\nHardware name: Red Hat KVM, BIOS\\nCall Trace:\\n\u003cTASK\u003e\\n__dump_stack lib/dump_stack.c:88 [inline]\\ndump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106\\nprint_address_description.constprop.9+0x28/0x160 mm/kasan/report.c:247\\nkasan_report_invalid_free+0x55/0x80 mm/kasan/report.c:372\\n____kasan_slab_free mm/kasan/common.c:346 [inline]\\n__kasan_slab_free+0x107/0x120 mm/kasan/common.c:374\\nkasan_slab_free include/linux/kasan.h:235 [inline]\\nslab_free_hook mm/slub.c:1723 [inline]\\nslab_free_freelist_hook mm/slub.c:1749 [inline]\\nslab_free mm/slub.c:3513 [inline]\\nkfree+0xac/0x2d0 mm/slub.c:4561\\nselinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605\\nsecurity_tun_dev_free_security+0x4f/0x90 security/security.c:2342\\ntun_free_netdev+0xe6/0x150 drivers/net/tun.c:2215\\nnetdev_run_todo+0x4df/0x840 net/core/dev.c:10627\\nrtnl_unlock+0x13/0x20 net/core/rtnetlink.c:112\\n__tun_chr_ioctl+0x80c/0x2870 drivers/net/tun.c:3302\\ntun_chr_ioctl+0x2f/0x40 drivers/net/tun.c:3311\\nvfs_ioctl fs/ioctl.c:51 [inline]\\n__do_sys_ioctl fs/ioctl.c:874 [inline]\\n__se_sys_ioctl fs/ioctl.c:860 [inline]\\n__x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860\\ndo_syscall_x64 arch/x86/entry/common.c:50 [inline]\\ndo_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80\\nentry_SYSCALL_64_after_hwframe+0x44/0xae\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"4.19.280\", \"versionStartIncluding\": \"3.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.240\", \"versionStartIncluding\": \"3.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.136\", \"versionStartIncluding\": \"3.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.12\", \"versionStartIncluding\": \"3.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.16\", \"versionStartIncluding\": \"3.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"3.10.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"3.11.5\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T08:45:53.877Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47082\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T08:45:53.877Z\", \"dateReserved\": \"2024-02-29T22:33:44.298Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-03-04T18:06:17.081Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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