{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slub: avoid zeroing outside-object freepointer for single free\n\nCommit 284f17ac13fe (\"mm/slub: handle bulk and single object freeing\nseparately\") splits single and bulk object freeing in two functions\nslab_free() and slab_free_bulk() which leads slab_free() to call\nslab_free_hook() directly instead of slab_free_freelist_hook().\n\nIf `init_on_free` is set, slab_free_hook() zeroes the object.\nAfterward, if `slub_debug=F` and `CONFIG_SLAB_FREELIST_HARDENED` are\nset, the do_slab_free() slowpath executes freelist consistency\nchecks and try to decode a zeroed freepointer which leads to a\n\"Freepointer corrupt\" detection in check_object().\n\nDuring bulk free, slab_free_freelist_hook() isn't affected as it always\nsets it objects freepointer using set_freepointer() to maintain its\nreconstructed freelist after `init_on_free`.\n\nFor single free, object's freepointer thus needs to be avoided when\nstored outside the object if `init_on_free` is set. The freepointer left\nas is, check_object() may later detect an invalid pointer value due to\nobjects overflow.\n\nTo reproduce, set `slub_debug=FU init_on_free=1 log_level=7` on the\ncommand line of a kernel build with `CONFIG_SLAB_FREELIST_HARDENED=y`.\n\ndmesg sample log:\n[   10.708715] =============================================================================\n[   10.710323] BUG kmalloc-rnd-05-32 (Tainted: G    B           T ): Freepointer corrupt\n[   10.712695] -----------------------------------------------------------------------------\n[   10.712695]\n[   10.712695] Slab 0xffffd8bdc400d580 objects=32 used=4 fp=0xffff9d9a80356f80 flags=0x200000000000a00(workingset|slab|node=0|zone=2)\n[   10.716698] Object 0xffff9d9a80356600 @offset=1536 fp=0x7ee4f480ce0ecd7c\n[   10.716698]\n[   10.716698] Bytes b4 ffff9d9a803565f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n[   10.720703] Object   ffff9d9a80356600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n[   10.720703] Object   ffff9d9a80356610: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n[   10.724696] Padding  ffff9d9a8035666c: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n[   10.724696] Padding  ffff9d9a8035667c: 00 00 00 00                                      ....\n[   10.724696] FIX kmalloc-rnd-05-32: Object at 0xffff9d9a80356600 not freed"
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "mm/slub.c"
               ],
               "versions": [
                  {
                     "version": "284f17ac13fe",
                     "lessThan": "56900355485f",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "284f17ac13fe",
                     "lessThan": "8f828aa48812",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "mm/slub.c"
               ],
               "versions": [
                  {
                     "version": "6.8",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "6.8",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.8.10",
                     "lessThanOrEqual": "6.8.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "6.9",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/56900355485f6e82114b18c812edd57fd7970dcb"
            },
            {
               "url": "https://git.kernel.org/stable/c/8f828aa48812ced28aa39cb3cfe55ef2444d03dd"
            }
         ],
         "title": "mm/slub: avoid zeroing outside-object freepointer for single free",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-36892",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}