{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix off by one issue in alloc_flex_gd()\n\nWesley reported an issue:\n\n==================================================================\nEXT4-fs (dm-5): resizing filesystem from 7168 to 786432 blocks\n------------[ cut here ]------------\nkernel BUG at fs/ext4/resize.c:324!\nCPU: 9 UID: 0 PID: 3576 Comm: resize2fs Not tainted 6.11.0+ #27\nRIP: 0010:ext4_resize_fs+0x1212/0x12d0\nCall Trace:\n __ext4_ioctl+0x4e0/0x1800\n ext4_ioctl+0x12/0x20\n __x64_sys_ioctl+0x99/0xd0\n x64_sys_call+0x1206/0x20d0\n do_syscall_64+0x72/0x110\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n==================================================================\n\nWhile reviewing the patch, Honza found that when adjusting resize_bg in\nalloc_flex_gd(), it was possible for flex_gd->resize_bg to be bigger than\nflexbg_size.\n\nThe reproduction of the problem requires the following:\n\n o_group = flexbg_size * 2 * n;\n o_size = (o_group + 1) * group_size;\n n_group: [o_group + flexbg_size, o_group + flexbg_size * 2)\n o_size = (n_group + 1) * group_size;\n\nTake n=0,flexbg_size=16 as an example:\n\n              last:15\n|o---------------|--------------n-|\no_group:0    resize to      n_group:30\n\nThe corresponding reproducer is:\n\nimg=test.img\nrm -f $img\ntruncate -s 600M $img\nmkfs.ext4 -F $img -b 1024 -G 16 8M\ndev=`losetup -f --show $img`\nmkdir -p /tmp/test\nmount $dev /tmp/test\nresize2fs $dev 248M\n\nDelete the problematic plus 1 to fix the issue, and add a WARN_ON_ONCE()\nto prevent the issue from happening again.\n\n[ Note: another reproucer which this commit fixes is:\n\n  img=test.img\n  rm -f $img\n  truncate -s 25MiB $img\n  mkfs.ext4 -b 4096 -E nodiscard,lazy_itable_init=0,lazy_journal_init=0 $img\n  truncate -s 3GiB $img\n  dev=`losetup -f --show $img`\n  mkdir -p /tmp/test\n  mount $dev /tmp/test\n  resize2fs $dev 3G\n  umount $dev\n  losetup -d $dev\n\n  -- TYT ]"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "fs/ext4/resize.c"
               ],
               "versions": [
                  {
                     "version": "665d3e0af4d3",
                     "lessThan": "0d80d2b8bf61",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "665d3e0af4d3",
                     "lessThan": "acb559d68261",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "665d3e0af4d3",
                     "lessThan": "6121258c2b33",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "fs/ext4/resize.c"
               ],
               "versions": [
                  {
                     "version": "6.8",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "6.8",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.10.14",
                     "lessThanOrEqual": "6.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.11.3",
                     "lessThanOrEqual": "6.11.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.12-rc2",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/0d80d2b8bf613398baf7185009e35f9d0459ecb0"
            },
            {
               "url": "https://git.kernel.org/stable/c/acb559d6826116cc113598640d105094620c2526"
            },
            {
               "url": "https://git.kernel.org/stable/c/6121258c2b33ceac3d21f6a221452692c465df88"
            }
         ],
         "title": "ext4: fix off by one issue in alloc_flex_gd()",
         "x_generator": {
            "engine": "bippy-c9c4e1df01b2"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-49880",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}