CVE-2024-26798

{"id": "CVE-2024-26798", "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": "2024-04-04T09:15:08.897", "references": [{"url": "https://git.kernel.org/stable/c/00d6a284fcf3fad1b7e1b5bc3cd87cbfb60ce03f", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/20a4b5214f7bee13c897477168c77bbf79683c3d", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/2f91a96b892fab2f2543b4a55740c5bee36b1a6b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/73a6bd68a1342f3a44cac9dffad81ad6a003e520", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a2c881413dcc5d801bdc9535e51270cc88cb9cd8", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/00d6a284fcf3fad1b7e1b5bc3cd87cbfb60ce03f", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/20a4b5214f7bee13c897477168c77bbf79683c3d", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/2f91a96b892fab2f2543b4a55740c5bee36b1a6b", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/73a6bd68a1342f3a44cac9dffad81ad6a003e520", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/a2c881413dcc5d801bdc9535e51270cc88cb9cd8", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-770"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbcon: always restore the old font data in fbcon_do_set_font()\n\nCommit a5a923038d70 (fbdev: fbcon: Properly revert changes when\nvc_resize() failed) started restoring old font data upon failure (of\nvc_resize()). But it performs so only for user fonts. It means that the\n\"system\"/internal fonts are not restored at all. So in result, the very\nfirst call to fbcon_do_set_font() performs no restore at all upon\nfailing vc_resize().\n\nThis can be reproduced by Syzkaller to crash the system on the next\ninvocation of font_get(). It's rather hard to hit the allocation failure\nin vc_resize() on the first font_set(), but not impossible. Esp. if\nfault injection is used to aid the execution/failure. It was\ndemonstrated by Sirius:\n BUG: unable to handle page fault for address: fffffffffffffff8\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n PGD cb7b067 P4D cb7b067 PUD cb7d067 PMD 0\n Oops: 0000 [#1] PREEMPT SMP KASAN\n CPU: 1 PID: 8007 Comm: poc Not tainted 6.7.0-g9d1694dc91ce #20\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\n RIP: 0010:fbcon_get_font+0x229/0x800 drivers/video/fbdev/core/fbcon.c:2286\n Call Trace:\n <TASK>\n con_font_get drivers/tty/vt/vt.c:4558 [inline]\n con_font_op+0x1fc/0xf20 drivers/tty/vt/vt.c:4673\n vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline]\n vt_ioctl+0x632/0x2ec0 drivers/tty/vt/vt_ioctl.c:752\n tty_ioctl+0x6f8/0x1570 drivers/tty/tty_io.c:2803\n vfs_ioctl fs/ioctl.c:51 [inline]\n ...\n\nSo restore the font data in any case, not only for user fonts. Note the\nlater 'if' is now protected by 'old_userfont' and not 'old_data' as the\nlatter is always set now. (And it is supposed to be non-NULL. Otherwise\nwe would see the bug above again.)"}, {"lang": "es", "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: fbcon: restaurar siempre los datos de fuentes antiguos en fbcon_do_set_font() commit a5a923038d70 (fbdev: fbcon: revertir correctamente los cambios cuando fall\u00f3 vc_resize()) comenz\u00f3 a restaurar los datos de fuentes antiguos en caso de falla (de vc_resize ()). Pero funciona s\u00f3lo para fuentes de usuario. Significa que las fuentes internas/del \"SYSTEM\" no se restauran en absoluto. Entonces, como resultado, la primera llamada a fbcon_do_set_font() no realiza ninguna restauraci\u00f3n al fallar vc_resize(). Syzkaller puede reproducir esto para bloquear el SYSTEM en la siguiente invocaci\u00f3n de font_get(). Es bastante dif\u00edcil solucionar el error de asignaci\u00f3n en vc_resize() en el primer font_set(), pero no imposible. Esp. si se utiliza la inyecci\u00f3n de fallos para ayudar en la ejecuci\u00f3n/fallo. Sirius lo demostr\u00f3: ERROR: no se puede manejar el error de p\u00e1gina para la direcci\u00f3n: fffffffffffffff8 #PF: acceso de lectura del supervisor en modo kernel #PF: error_code(0x0000) - p\u00e1gina no presente PGD cb7b067 P4D cb7b067 PUD cb7d067 PMD 0 Ups: 0000 [ #1] PREEMPT SMP KASAN CPU: 1 PID: 8007 Comm: poc No contaminado 6.7.0-g9d1694dc91ce #20 Nombre del hardware: PC est\u00e1ndar QEMU (i440FX + PIIX, 1996), BIOS 1.15.0-1 01/04/2014 RIP : 0010:fbcon_get_font+0x229/0x800 drivers/video/fbdev/core/fbcon.c:2286 Seguimiento de llamadas: con_font_get drivers/tty/vt/vt.c:4558 [en l\u00ednea] con_font_op+0x1fc/0xf20 drivers/tty /vt/vt.c:4673 controladores vt_k_ioctl/tty/vt/vt_ioctl.c:474 [en l\u00ednea] vt_ioctl+0x632/0x2ec0 controladores/tty/vt/vt_ioctl.c:752 tty_ioctl+0x6f8/0x1570 controladores/tty/tty_io. c:2803 vfs_ioctl fs/ioctl.c:51 [en l\u00ednea] ... As\u00ed que restaure los datos de fuente en cualquier caso, no solo para las fuentes del usuario. Tenga en cuenta que el 'if' posterior ahora est\u00e1 protegido por 'old_userfont' y no por 'old_data' ya que este \u00faltimo siempre est\u00e1 configurado ahora. (Y se supone que no es NULL. De lo contrario, volver\u00edamos a ver el error anterior)."}], "lastModified": "2025-04-01T20:35:32.650", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C6852C0F-A534-43B3-BDC6-ECFEF26AB7DB", "versionEndExcluding": "5.15.151", "versionStartIncluding": "5.15.64"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "89A51AC3-83B4-4F44-B496-385D10612456", "versionEndExcluding": "6.1.81", "versionStartIncluding": "6.0"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B19074A2-9FE5-4E7D-9E2D-020F95013ADA", "versionEndExcluding": "6.6.21", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1C538467-EDA0-4A9A-82EB-2925DE9FF827", "versionEndExcluding": "6.7.9", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B9F4EA73-0894-400F-A490-3A397AB7A517"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "056BD938-0A27-4569-B391-30578B309EE3"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F02056A5-B362-4370-9FF8-6F0BD384D520"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "62075ACE-B2A0-4B16-829D-B3DA5AE5CC41"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A780F817-2A77-4130-A9B7-5C25606314E3"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.8:rc6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AEB9199B-AB8F-4877-8964-E2BA95B5F15C"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}