CVE-2021-46986

{"id": "CVE-2021-46986", "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": "2024-02-28T09:15:37.540", "references": [{"url": "https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/1ea775021282d90e1d08d696b7ab54aa75d688e5", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/b4b8e9601d7ee8806d2687f081a42485d27674a1", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/bb9c74a5bd1462499fe5ccb1e3c5ac40dcfa9139", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/bc0cdd72493236fb72b390ad38ce581e353c143c", "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\nusb: dwc3: gadget: Free gadget structure only after freeing endpoints\n\nAs part of commit e81a7018d93a (\"usb: dwc3: allocate gadget structure\ndynamically\") the dwc3_gadget_release() was added which will free\nthe dwc->gadget structure upon the device's removal when\nusb_del_gadget_udc() is called in dwc3_gadget_exit().\n\nHowever, simply freeing the gadget results a dangling pointer\nsituation: the endpoints created in dwc3_gadget_init_endpoints()\nhave their dep->endpoint.ep_list members chained off the list_head\nanchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,\nthe first dwc3_ep in the list now has a dangling prev pointer and\nlikewise for the next pointer of the dwc3_ep at the tail of the list.\nThe dwc3_gadget_free_endpoints() that follows will result in a\nuse-after-free when it calls list_del().\n\nThis was caught by enabling KASAN and performing a driver unbind.\nThe recent commit 568262bf5492 (\"usb: dwc3: core: Add shutdown\ncallback for dwc3\") also exposes this as a panic during shutdown.\n\nThere are a few possibilities to fix this. One could be to perform\na list_del() of the gadget->ep_list itself which removes it from\nthe rest of the dwc3_ep chain.\n\nAnother approach is what this patch does, by splitting up the\nusb_del_gadget_udc() call into its separate \"del\" and \"put\"\ncomponents. This allows dwc3_gadget_free_endpoints() to be\ncalled before the gadget is finally freed with usb_put_gadget()."}, {"lang": "es", "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: usb: dwc3: gadget: estructura de gadget libre solo despu\u00e9s de liberar los puntos finales. Como parte de el commit e81a7018d93a (\"usb: dwc3: asignar estructura de gadget din\u00e1micamente\"), se agreg\u00f3 dwc3_gadget_release() que libere la estructura dwc->gadget al retirar el dispositivo cuando se llama a usb_del_gadget_udc() en dwc3_gadget_exit(). Sin embargo, simplemente liberar el gadget da como resultado una situaci\u00f3n de puntero colgante: los puntos finales creados en dwc3_gadget_init_endpoints() tienen sus miembros dep->endpoint.ep_list encadenados fuera del list_head anclado en dwc->gadget->ep_list. Por lo tanto, cuando se libera dwc->gadget, el primer dwc3_ep de la lista ahora tiene un puntero anterior colgante y lo mismo ocurre con el siguiente puntero de dwc3_ep al final de la lista. El dwc3_gadget_free_endpoints() que sigue dar\u00e1 como resultado un use-after-free cuando llame a list_del(). Esto se detect\u00f3 habilitando KASAN y realizando una desvinculaci\u00f3n del controlador. La reciente confirmaci\u00f3n 568262bf5492 (\"usb: dwc3: core: Add Shutdown Callback for dwc3\") tambi\u00e9n expone esto como un p\u00e1nico durante el apagado. Hay algunas posibilidades para solucionar este problema. Una podr\u00eda ser realizar un list_del() del propio gadget->ep_list que lo elimine del resto de la cadena dwc3_ep. Otro enfoque es lo que hace este parche, al dividir la llamada usb_del_gadget_udc() en sus componentes separados \"del\" y \"put\". Esto permite llamar a dwc3_gadget_free_endpoints() antes de que el gadget se libere finalmente con usb_put_gadget()."}], "lastModified": "2024-12-31T16:14:55.390", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8051E54C-C4D7-4B79-90C8-3C0B5A772262", "versionEndExcluding": "5.10.38", "versionStartIncluding": "5.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "83B53E9A-F426-4C03-9A5F-A931FF79827E", "versionEndExcluding": "5.11.22", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0274929A-B36C-4F4C-AB22-30A0DD6B995B", "versionEndExcluding": "5.12.5", "versionStartIncluding": "5.12"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}