CVE-2021-46981

{"id": "CVE-2021-46981", "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": "2024-02-28T09:15:37.320", "references": [{"url": "https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/1c4962df938891af9ab4775f5224ef8601764107", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/54b78ba7e96e5fe1edb8054e375d31a6c0dc60dc", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/79ebe9110fa458d58f1fceb078e2068d7ad37390", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/b31d237796fd618379ec8e0f4de3370b5e4aeee7", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/cde4b55cfb24522dcbba80bbdb0c082303e76c43", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: Fix NULL pointer in flush_workqueue\n\nOpen /dev/nbdX first, the config_refs will be 1 and\nthe pointers in nbd_device are still null. Disconnect\n/dev/nbdX, then reference a null recv_workq. The\nprotection by config_refs in nbd_genl_disconnect is useless.\n\n[ 656.366194] BUG: kernel NULL pointer dereference, address: 0000000000000020\n[ 656.368943] #PF: supervisor write access in kernel mode\n[ 656.369844] #PF: error_code(0x0002) - not-present page\n[ 656.370717] PGD 10cc87067 P4D 10cc87067 PUD 1074b4067 PMD 0\n[ 656.371693] Oops: 0002 [#1] SMP\n[ 656.372242] CPU: 5 PID: 7977 Comm: nbd-client Not tainted 5.11.0-rc5-00040-g76c057c84d28 #1\n[ 656.373661] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014\n[ 656.375904] RIP: 0010:mutex_lock+0x29/0x60\n[ 656.376627] Code: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 <f0> 48 0f b1 55 d\n[ 656.378934] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246\n[ 656.379350] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\n[ 656.379915] RDX: ffff888104cf2600 RSI: ffffffffaae8f452 RDI: 0000000000000020\n[ 656.380473] RBP: 0000000000000020 R08: 0000000000000000 R09: ffff88813bd6b318\n[ 656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40\n[ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00\n[ 656.382166] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000\n[ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0\n[ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[ 656.384927] Call Trace:\n[ 656.385111] flush_workqueue+0x92/0x6c0\n[ 656.385395] nbd_disconnect_and_put+0x81/0xd0\n[ 656.385716] nbd_genl_disconnect+0x125/0x2a0\n[ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0\n[ 656.386422] genl_rcv_msg+0xfc/0x2b0\n[ 656.386685] ? nbd_ioctl+0x490/0x490\n[ 656.386954] ? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0\n[ 656.387354] netlink_rcv_skb+0x62/0x180\n[ 656.387638] genl_rcv+0x34/0x60\n[ 656.387874] netlink_unicast+0x26d/0x590\n[ 656.388162] netlink_sendmsg+0x398/0x6c0\n[ 656.388451] ? netlink_rcv_skb+0x180/0x180\n[ 656.388750] ____sys_sendmsg+0x1da/0x320\n[ 656.389038] ? ____sys_recvmsg+0x130/0x220\n[ 656.389334] ___sys_sendmsg+0x8e/0xf0\n[ 656.389605] ? ___sys_recvmsg+0xa2/0xf0\n[ 656.389889] ? handle_mm_fault+0x1671/0x21d0\n[ 656.390201] __sys_sendmsg+0x6d/0xe0\n[ 656.390464] __x64_sys_sendmsg+0x23/0x30\n[ 656.390751] do_syscall_64+0x45/0x70\n[ 656.391017] entry_SYSCALL_64_after_hwframe+0x44/0xa9\n\nTo fix it, just add if (nbd->recv_workq) to nbd_disconnect_and_put()."}, {"lang": "es", "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: nbd: corrija el puntero NULL en flush_workqueue Abra /dev/nbdX primero, config_refs ser\u00e1 1 y los punteros en nbd_device seguir\u00e1n siendo nulos. Desconecte /dev/nbdX, luego haga referencia a un recv_workq nulo. La protecci\u00f3n de config_refs en nbd_genl_disconnect es in\u00fatil. [656.366194] ERROR: desreferencia del puntero NULL del kernel, direcci\u00f3n: 00000000000000020 [656.368943] #PF: acceso de escritura del supervisor en modo kernel [656.369844] #PF: c\u00f3digo_error(0x0002) - p\u00e1gina no presente [656.370717] PGD 10cc87067 P 4D 10cc87067 PUD 1074b4067 PMD 0 [656.371693] Ups: 0002 [#1] SMP [656.372242] CPU: 5 PID: 7977 Comm: nbd-client No contaminado 5.11.0-rc5-00040-g76c057c84d28 #1 [656.373661] Nombre de hardware: PC est\u00e1ndar QEMU (i 440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 01/04/2014 [ 656.375904] RIP: 0010:mutex_lock+0x29/0x60 [ 656.376627] C\u00f3digo: 00 0f 1f 44 00 00 55 48 89 fd 48 83 05 6f d7 fe 08 01 e8 7a c3 ff ff 48 83 05 6a d7 fe 08 01 31 c0 65 48 8b 14 25 00 6d 01 00 48 0f b1 55 d [ 656.378934 ] RSP: 0018:ffffc900005eb9b0 EFLAGS: 00010246 [ 656.379350] RAX: 0000000000000000 RBX: 00000000000000000 RCX: 0000000000000000 [ 656.379915 ] RDX: ffff888104cf2600 RSI: fffffffaae8f452 RDI: 0000000000000020 [ 656.380473] RBP: 00000000000000020 R08: 00000000000000000 R09: ffff88813bd6b31 8 [656.381039] R10: 00000000000000c7 R11: fefefefefefefeff R12: ffff888102710b40 [ 656.381599] R13: ffffc900005eb9e0 R14: ffffffffb2930680 R15: ffff88810770ef00 [ 656.3821 66] FS: 00007fdf117ebb40(0000) GS:ffff88813bd40000(0000) knlGS:0000000000000000 [ 656.382806] CS: 0010 DS: 0000 ES: 0000 CR0 : 0000000080050033 [ 656.383261] CR2: 0000000000000020 CR3: 0000000100c84000 CR4: 00000000000006e0 [ 656.383819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 656.384370] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 656.384927] Seguimiento de llamadas : [656.385111] flux_workqueue+0x92 /0x6c0 [ 656.385395] nbd_disconnect_and_put+0x81/0xd0 [ 656.385716] nbd_genl_disconnect+0x125/0x2a0 [ 656.386034] genl_family_rcv_msg_doit.isra.0+0x102/0x1b0 [ 656 .386422] genl_rcv_msg+0xfc/0x2b0 [656.386685]? nbd_ioctl+0x490/0x490 [656.386954]? genl_family_rcv_msg_doit.isra.0+0x1b0/0x1b0 [ 656.387354] netlink_rcv_skb+0x62/0x180 [ 656.387638] genl_rcv+0x34/0x60 [ 656.387874] netlink_unicast+0x26d/0x590 [ 6 56.388162] netlink_sendmsg+0x398/0x6c0 [656.388451]? netlink_rcv_skb+0x180/0x180 [656.388750] ____sys_sendmsg+0x1da/0x320 [656.389038] ? ____sys_recvmsg+0x130/0x220 [ 656.389334] ___sys_sendmsg+0x8e/0xf0 [ 656.389605] ? ___sys_recvmsg+0xa2/0xf0 [656.389889] ? handle_mm_fault+0x1671/0x21d0 [ 656.390201] __sys_sendmsg+0x6d/0xe0 [ 656.390464] __x64_sys_sendmsg+0x23/0x30 [ 656.390751] do_syscall_64+0x45/0x70 [656.391017] Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Para solucionarlo, simplemente agregue if (nbd-&gt;recv_workq) a nbd_disconnect_and_put()."}], "lastModified": "2024-12-06T15:59:55.120", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "74E02350-43FB-4F4F-B822-E9CA42371263", "versionEndExcluding": "5.4.120", "versionStartIncluding": "5.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2BB4E5E8-4AAD-475A-A1B9-F287254C7D72", "versionEndExcluding": "5.10.38", "versionStartIncluding": "5.5"}, {"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"}