{
   "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 kmalloc redzone\n\nSince commit 946fa0dbf2d8 (\"mm/slub: extend redzone check to extra\nallocated kmalloc space than requested\"), setting orig_size treats\nthe wasted space (object_size - orig_size) as a redzone. However with\ninit_on_free=1 we clear the full object->size, including the redzone.\n\nAdditionally we clear the object metadata, including the stored orig_size,\nmaking it zero, which makes check_object() treat the whole object as a\nredzone.\n\nThese issues lead to the following BUG report with \"slub_debug=FUZ\ninit_on_free=1\":\n\n[    0.000000] =============================================================================\n[    0.000000] BUG kmalloc-8 (Not tainted): kmalloc Redzone overwritten\n[    0.000000] -----------------------------------------------------------------------------\n[    0.000000]\n[    0.000000] 0xffff000010032858-0xffff00001003285f @offset=2136. First byte 0x0 instead of 0xcc\n[    0.000000] FIX kmalloc-8: Restoring kmalloc Redzone 0xffff000010032858-0xffff00001003285f=0xcc\n[    0.000000] Slab 0xfffffdffc0400c80 objects=36 used=23 fp=0xffff000010032a18 flags=0x3fffe0000000200(workingset|node=0|zone=0|lastcpupid=0x1ffff)\n[    0.000000] Object 0xffff000010032858 @offset=2136 fp=0xffff0000100328c8\n[    0.000000]\n[    0.000000] Redzone  ffff000010032850: cc cc cc cc cc cc cc cc                          ........\n[    0.000000] Object   ffff000010032858: cc cc cc cc cc cc cc cc                          ........\n[    0.000000] Redzone  ffff000010032860: cc cc cc cc cc cc cc cc                          ........\n[    0.000000] Padding  ffff0000100328b4: 00 00 00 00 00 00 00 00 00 00 00 00              ............\n[    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.11.0-rc3-next-20240814-00004-g61844c55c3f4 #144\n[    0.000000] Hardware name: NXP i.MX95 19X19 board (DT)\n[    0.000000] Call trace:\n[    0.000000]  dump_backtrace+0x90/0xe8\n[    0.000000]  show_stack+0x18/0x24\n[    0.000000]  dump_stack_lvl+0x74/0x8c\n[    0.000000]  dump_stack+0x18/0x24\n[    0.000000]  print_trailer+0x150/0x218\n[    0.000000]  check_object+0xe4/0x454\n[    0.000000]  free_to_partial_list+0x2f8/0x5ec\n\nTo address the issue, use orig_size to clear the used area. And restore\nthe value of orig_size after clear the remaining area.\n\nWhen CONFIG_SLUB_DEBUG not defined, (get_orig_size()' directly returns\ns->object_size. So when using memset to init the area, the size can simply\nbe orig_size, as orig_size returns object_size when CONFIG_SLUB_DEBUG not\nenabled. And orig_size can never be bigger than object_size."
            }
         ],
         "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": "946fa0dbf2d8",
                     "lessThan": "7a2e823a1974",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "946fa0dbf2d8",
                     "lessThan": "83f0440b2f92",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "946fa0dbf2d8",
                     "lessThan": "59090e479ac7",
                     "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": "6.2",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "6.2",
                     "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/7a2e823a19746d54052c625faecf0d2d6c52ee0a"
            },
            {
               "url": "https://git.kernel.org/stable/c/83f0440b2f92227fcce9898118ca7fe7e0d64b1f"
            },
            {
               "url": "https://git.kernel.org/stable/c/59090e479ac78ae18facd4c58eb332562a23020e"
            }
         ],
         "title": "mm, slub: avoid zeroing kmalloc redzone",
         "x_generator": {
            "engine": "bippy-c9c4e1df01b2"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2024-49885",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}