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Home CVE Database CVE-2021-47162

CVE-2021-47162

Description

In the Linux kernel, the following vulnerability has been resolved: tipc: skb_linearize the head skb when reassembling msgs It\'s not a good idea to append the frag skb to a skb\'s frag_list if the frag_list already has skbs from elsewhere, such as this skb was created by pskb_copy() where the frag_list was cloned (all the skbs in it were skb_get\'ed) and shared by multiple skbs. However, the new appended frag skb should have been only seen by the current skb. Otherwise, it will cause use after free crashes as this appended frag skb are seen by multiple skbs but it only got skb_get called once. The same thing happens with a skb updated by pskb_may_pull() with a skb_cloned skb. Li Shuang has reported quite a few crashes caused by this when doing testing over macvlan devices: [] kernel BUG at net/core/skbuff.c:1970! [] Call Trace: [] skb_clone+0x4d/0xb0 [] macvlan_broadcast+0xd8/0x160 [macvlan] [] macvlan_process_broadcast+0x148/0x150 [macvlan] [] process_one_work+0x1a7/0x360 [] worker_thread+0x30/0x390 [] kernel BUG at mm/usercopy.c:102! [] Call Trace: [] __check_heap_object+0xd3/0x100 [] __check_object_size+0xff/0x16b [] simple_copy_to_iter+0x1c/0x30 [] __skb_datagram_iter+0x7d/0x310 [] __skb_datagram_iter+0x2a5/0x310 [] skb_copy_datagram_iter+0x3b/0x90 [] tipc_recvmsg+0x14a/0x3a0 [tipc] [] ____sys_recvmsg+0x91/0x150 [] ___sys_recvmsg+0x7b/0xc0 [] kernel BUG at mm/slub.c:305! [] Call Trace: [] <IRQ> [] kmem_cache_free+0x3ff/0x400 [] __netif_receive_skb_core+0x12c/0xc40 [] ? kmem_cache_alloc+0x12e/0x270 [] netif_receive_skb_internal+0x3d/0xb0 [] ? get_rx_page_info+0x8e/0xa0 [be2net] [] be_poll+0x6ef/0xd00 [be2net] [] ? irq_exit+0x4f/0x100 [] net_rx_action+0x149/0x3b0 ... This patch is to fix it by linearizing the head skb if it has frag_list set in tipc_buf_append(). Note that we choose to do this before calling skb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can not just drop the frag_list either as the early time.

Priority: --
CVSS v3: --
Component: linux
Publish Date: Mar 25, 2024
Related ID: --
CVSS v2: --
Modified Date: Mar 25, 2024

Find out more about CVE-2021-47162 from the MITRE-CVE dictionary and NIST NVD


Products Affected

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Product Name Status Defect Fixed Downloads
Linux
Wind River Linux LTS 17 Requires LTSS -- -- --
Wind River Linux 8 Requires LTSS -- -- --
Wind River Linux 9 Requires LTSS -- -- --
Wind River Linux 7 Requires LTSS -- -- --
Wind River Linux LTS 21 Fixed LIN1021-7866
10.21.20.21 --
Wind River Linux LTS 22 Not Vulnerable -- -- --
Wind River Linux LTS 18 Requires LTSS -- -- --
Wind River Linux LTS 19 Fixed LIN1019-11535
10.19.45.30 --
Wind River Linux CD release N/A -- -- --
Wind River Linux 6 Requires LTSS -- -- --
Wind River Linux LTS 23 Not Vulnerable -- -- --
VxWorks
VxWorks 7 Not Vulnerable -- -- --
VxWorks 6.9 Not Vulnerable -- -- --
Helix Virtualization Platform Cert Edition
Helix Virtualization Platform Cert Edition Not Vulnerable -- -- --
eLxr
eLxr 12 Not Vulnerable -- -- --

Related Products

Product Name Status Defect Fixed Downloads

Notes
Requires LTSS - customers must have active LTSS (Long Term Security Shield) Support to receive up-to-date information about vulnerabilities that may affect legacy software. Please contact your Wind River account team or see https://docs.windriver.com/bundle/Support_and_Maintenance_Supplemental_Terms_and_Conditions and https://support2.windriver.com/index.php?page=plc for more information.
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