{
   "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 double brelse() the buffer of the extents path\n\nIn ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been\nreleased, otherwise it may be released twice. An example of what triggers\nthis is as follows:\n\n  split2    map    split1\n|--------|-------|--------|\n\next4_ext_map_blocks\n ext4_ext_handle_unwritten_extents\n  ext4_split_convert_extents\n   // path->p_depth == 0\n   ext4_split_extent\n     // 1. do split1\n     ext4_split_extent_at\n       |ext4_ext_insert_extent\n       |  ext4_ext_create_new_leaf\n       |    ext4_ext_grow_indepth\n       |      le16_add_cpu(&neh->eh_depth, 1)\n       |    ext4_find_extent\n       |      // return -ENOMEM\n       |// get error and try zeroout\n       |path = ext4_find_extent\n       |  path->p_depth = 1\n       |ext4_ext_try_to_merge\n       |  ext4_ext_try_to_merge_up\n       |    path->p_depth = 0\n       |    brelse(path[1].p_bh)  ---> not set to NULL here\n       |// zeroout success\n     // 2. update path\n     ext4_find_extent\n     // 3. do split2\n     ext4_split_extent_at\n       ext4_ext_insert_extent\n         ext4_ext_create_new_leaf\n           ext4_ext_grow_indepth\n             le16_add_cpu(&neh->eh_depth, 1)\n           ext4_find_extent\n             path[0].p_bh = NULL;\n             path->p_depth = 1\n             read_extent_tree_block  ---> return err\n             // path[1].p_bh is still the old value\n             ext4_free_ext_path\n               ext4_ext_drop_refs\n                 // path->p_depth == 1\n                 brelse(path[1].p_bh)  ---> brelse a buffer twice\n\nFinally got the following WARRNING when removing the buffer from lru:\n\n============================================\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90\nCPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716\nRIP: 0010:__brelse+0x58/0x90\nCall Trace:\n <TASK>\n __find_get_block+0x6e7/0x810\n bdev_getblk+0x2b/0x480\n __ext4_get_inode_loc+0x48a/0x1240\n ext4_get_inode_loc+0xb2/0x150\n ext4_reserve_inode_write+0xb7/0x230\n __ext4_mark_inode_dirty+0x144/0x6a0\n ext4_ext_insert_extent+0x9c8/0x3230\n ext4_ext_map_blocks+0xf45/0x2dc0\n ext4_map_blocks+0x724/0x1700\n ext4_do_writepages+0x12d6/0x2a70\n[...]\n============================================"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "fs/ext4/extents.c"
               ],
               "versions": [
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "b6c29c8f3d7c",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "32bbb59e3f18",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "78bbc3d15b6f",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "68a69cf60660",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "7633407ca4ab",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "230ee0535d01",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "ecb94f5fdf4b",
                     "lessThan": "dcaa6c31134c",
                     "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/extents.c"
               ],
               "versions": [
                  {
                     "version": "3.7",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "3.7",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.227",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15.168",
                     "lessThanOrEqual": "5.15.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.1.113",
                     "lessThanOrEqual": "6.1.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.6.55",
                     "lessThanOrEqual": "6.6.*",
                     "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-rc1",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e"
            },
            {
               "url": "https://git.kernel.org/stable/c/32bbb59e3f18facd7201bef110010bf35819b8c3"
            },
            {
               "url": "https://git.kernel.org/stable/c/78bbc3d15b6f443acb26e94418c445bac940d414"
            },
            {
               "url": "https://git.kernel.org/stable/c/68a69cf60660c73990c1875f94a5551600b04775"
            },
            {
               "url": "https://git.kernel.org/stable/c/7633407ca4ab8be2916ab214eb44ccebc6a50e1a"
            },
            {
               "url": "https://git.kernel.org/stable/c/230ee0535d01478bad9a3037292043f39b9be10b"
            },
            {
               "url": "https://git.kernel.org/stable/c/dcaa6c31134c0f515600111c38ed7750003e1b9c"
            }
         ],
         "title": "ext4: fix double brelse() the buffer of the extents path",
         "x_generator": {
            "engine": "bippy-c9c4e1df01b2"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-49882",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}