CVE-2021-47162

{"id": "CVE-2021-47162", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2024-03-25T10:15:08.480", "references": [{"url": "https://git.kernel.org/stable/c/436d650d374329a591c30339a91fa5078052ed1e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/4b1761898861117c97066aea6c58f68a7787f0bf", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/5489f30bb78ff0dafb4229a69632afc2ba20765c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/64d17ec9f1ded042c4b188d15734f33486ed9966", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6da24cfc83ba4f97ea44fc7ae9999a006101755c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ace300eecbccaa698e2b472843c74a5f33f7dce8", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b2c8d28c34b3070407cb1741f9ba3f15d0284b8b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b7df21cf1b79ab7026f545e7bf837bd5750ac026", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/436d650d374329a591c30339a91fa5078052ed1e", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/4b1761898861117c97066aea6c58f68a7787f0bf", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/5489f30bb78ff0dafb4229a69632afc2ba20765c", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/64d17ec9f1ded042c4b188d15734f33486ed9966", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/6da24cfc83ba4f97ea44fc7ae9999a006101755c", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/ace300eecbccaa698e2b472843c74a5f33f7dce8", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/b2c8d28c34b3070407cb1741f9ba3f15d0284b8b", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/b7df21cf1b79ab7026f545e7bf837bd5750ac026", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: skb_linearize the head skb when reassembling msgs\n\nIt's not a good idea to append the frag skb to a skb's frag_list if\nthe frag_list already has skbs from elsewhere, such as this skb was\ncreated by pskb_copy() where the frag_list was cloned (all the skbs\nin it were skb_get'ed) and shared by multiple skbs.\n\nHowever, the new appended frag skb should have been only seen by the\ncurrent skb. Otherwise, it will cause use after free crashes as this\nappended frag skb are seen by multiple skbs but it only got skb_get\ncalled once.\n\nThe same thing happens with a skb updated by pskb_may_pull() with a\nskb_cloned skb. Li Shuang has reported quite a few crashes caused\nby this when doing testing over macvlan devices:\n\n [] kernel BUG at net/core/skbuff.c:1970!\n [] Call Trace:\n [] skb_clone+0x4d/0xb0\n [] macvlan_broadcast+0xd8/0x160 [macvlan]\n [] macvlan_process_broadcast+0x148/0x150 [macvlan]\n [] process_one_work+0x1a7/0x360\n [] worker_thread+0x30/0x390\n\n [] kernel BUG at mm/usercopy.c:102!\n [] Call Trace:\n [] __check_heap_object+0xd3/0x100\n [] __check_object_size+0xff/0x16b\n [] simple_copy_to_iter+0x1c/0x30\n [] __skb_datagram_iter+0x7d/0x310\n [] __skb_datagram_iter+0x2a5/0x310\n [] skb_copy_datagram_iter+0x3b/0x90\n [] tipc_recvmsg+0x14a/0x3a0 [tipc]\n [] ____sys_recvmsg+0x91/0x150\n [] ___sys_recvmsg+0x7b/0xc0\n\n [] kernel BUG at mm/slub.c:305!\n [] Call Trace:\n [] <IRQ>\n [] kmem_cache_free+0x3ff/0x400\n [] __netif_receive_skb_core+0x12c/0xc40\n [] ? kmem_cache_alloc+0x12e/0x270\n [] netif_receive_skb_internal+0x3d/0xb0\n [] ? get_rx_page_info+0x8e/0xa0 [be2net]\n [] be_poll+0x6ef/0xd00 [be2net]\n [] ? irq_exit+0x4f/0x100\n [] net_rx_action+0x149/0x3b0\n\n ...\n\nThis patch is to fix it by linearizing the head skb if it has frag_list\nset in tipc_buf_append(). Note that we choose to do this before calling\nskb_unshare(), as __skb_linearize() will avoid skb_copy(). Also, we can\nnot just drop the frag_list either as the early time."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tipc: skb_linearize el skb principal al volver a ensamblar mensajes No es una buena idea agregar el frag skb a la frag_list de un skb si la frag_list ya tiene skbs de otro lugar, como por ejemplo este skb fue creado por pskb_copy() donde se clon\u00f3 frag_list (todos los skbs que conten\u00eda fueron skb_get'ed) y se comparti\u00f3 con varios skbs. Sin embargo, el nuevo fragmento skb adjunto solo deber\u00eda haber sido visto por el skb actual. De lo contrario, causar\u00e1 uso despu\u00e9s de fallas gratuitas, ya que varios skbs ven este fragmento skb agregado, pero solo se llam\u00f3 a skb_get una vez. Lo mismo sucede con un skb actualizado por pskb_may_pull() con un skb skb_cloned. Li Shuang ha informado de bastantes fallos causados por esto al realizar pruebas en dispositivos macvlan: [] \u00a1ERROR del kernel en net/core/skbuff.c:1970! [] Seguimiento de llamadas: [] skb_clone+0x4d/0xb0 [] macvlan_broadcast+0xd8/0x160 [macvlan] [] macvlan_process_broadcast+0x148/0x150 [macvlan] [] Process_one_work+0x1a7/0x360 [] trabajador_thread+0x30/0x390 [] ERROR del kernel en mm/usercopy.c:102! [] Seguimiento de llamadas: [] __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 [] \u00a1ERROR del kernel en mm/slub.c:305! [] Seguimiento de llamadas: [] [] 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 ... Este parche es para solucionarlo linealizando el skb principal si tiene frag_list configurado en tipc_buf_append(). Tenga en cuenta que elegimos hacer esto antes de llamar a skb_unshare(), ya que __skb_linearize() evitar\u00e1 skb_copy(). Adem\u00e1s, tampoco podemos simplemente eliminar frag_list desde el principio."}], "lastModified": "2025-03-13T21:23:24.410", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "48D6EB76-316E-412C-B3FF-6500D60AB68E", "versionEndExcluding": "4.4.271", "versionStartIncluding": "4.3"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1E7DAE3A-78E9-45DB-96D8-4541CD7DC26B", "versionEndExcluding": "4.9.271", "versionStartIncluding": "4.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "03A23445-0C1A-42AB-AC5C-768360DDF32C", "versionEndExcluding": "4.14.235", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C8DEF3EC-88D9-4B89-8CF9-64BD6C863C9D", "versionEndExcluding": "4.19.193", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "06FE0F99-F7A9-462A-8355-30E2EDA9826B", "versionEndExcluding": "5.4.124", "versionStartIncluding": "4.20"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C3E7E799-1C8A-45FB-9E07-4731996144C9", "versionEndExcluding": "5.10.42", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2C8A1D02-81A7-44E5-ACFD-CC6A6694F930", "versionEndExcluding": "5.12.9", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}