{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "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.)"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "drivers/video/fbdev/core/fbcon.c"
               ],
               "versions": [
                  {
                     "version": "ebd6f886aa24",
                     "lessThan": "20a4b5214f7b",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "a5a923038d70",
                     "lessThan": "2f91a96b892f",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "a5a923038d70",
                     "lessThan": "73a6bd68a134",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "a5a923038d70",
                     "lessThan": "a2c881413dcc",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "a5a923038d70",
                     "lessThan": "00d6a284fcf3",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "drivers/video/fbdev/core/fbcon.c"
               ],
               "versions": [
                  {
                     "version": "6.0",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "6.0",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.151",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.81",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.21",
                     "lessThanOrEqual": "6.6.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.7.9",
                     "lessThanOrEqual": "6.7.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.8",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/20a4b5214f7bee13c897477168c77bbf79683c3d"
            },
            {
               "url": "https://git.kernel.org/stable/c/2f91a96b892fab2f2543b4a55740c5bee36b1a6b"
            },
            {
               "url": "https://git.kernel.org/stable/c/73a6bd68a1342f3a44cac9dffad81ad6a003e520"
            },
            {
               "url": "https://git.kernel.org/stable/c/a2c881413dcc5d801bdc9535e51270cc88cb9cd8"
            },
            {
               "url": "https://git.kernel.org/stable/c/00d6a284fcf3fad1b7e1b5bc3cd87cbfb60ce03f"
            }
         ],
         "title": "fbcon: always restore the old font data in fbcon_do_set_font()",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-26798",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}