{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.1",
    "cveMetadata": {
        "cveId": "CVE-2024-40955",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2024-07-12T12:17:45.592Z",
        "datePublished": "2024-07-12T12:31:58.328Z",
        "dateUpdated": "2024-09-11T17:34:24.264Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2024-07-15T06:52:09.181Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists()\n\nWe can trigger a slab-out-of-bounds with the following commands:\n\n    mkfs.ext4 -F /dev/$disk 10G\n    mount /dev/$disk /tmp/test\n    echo 2147483647 > /sys/fs/ext4/$disk/mb_group_prealloc\n    echo test > /tmp/test/file && sync\n\n==================================================================\nBUG: KASAN: slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4]\nRead of size 8 at addr ffff888121b9d0f0 by task kworker/u2:0/11\nCPU: 0 PID: 11 Comm: kworker/u2:0 Tainted: GL 6.7.0-next-20240118 #521\nCall Trace:\n dump_stack_lvl+0x2c/0x50\n kasan_report+0xb6/0xf0\n ext4_mb_find_good_group_avg_frag_lists+0x8a/0x200 [ext4]\n ext4_mb_regular_allocator+0x19e9/0x2370 [ext4]\n ext4_mb_new_blocks+0x88a/0x1370 [ext4]\n ext4_ext_map_blocks+0x14f7/0x2390 [ext4]\n ext4_map_blocks+0x569/0xea0 [ext4]\n ext4_do_writepages+0x10f6/0x1bc0 [ext4]\n[...]\n==================================================================\n\nThe flow of issue triggering is as follows:\n\n// Set s_mb_group_prealloc to 2147483647 via sysfs\next4_mb_new_blocks\n  ext4_mb_normalize_request\n    ext4_mb_normalize_group_request\n      ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc\n  ext4_mb_regular_allocator\n    ext4_mb_choose_next_group\n      ext4_mb_choose_next_group_best_avail\n        mb_avg_fragment_size_order\n          order = fls(len) - 2 = 29\n        ext4_mb_find_good_group_avg_frag_lists\n          frag_list = &sbi->s_mb_avg_fragment_size[order]\n          if (list_empty(frag_list)) // Trigger SOOB!\n\nAt 4k block size, the length of the s_mb_avg_fragment_size list is 14,\nbut an oversized s_mb_group_prealloc is set, causing slab-out-of-bounds\nto be triggered by an attempt to access an element at index 29.\n\nAdd a new attr_id attr_clusters_in_group with values in the range\n[0, sbi->s_clusters_per_group] and declare mb_group_prealloc as\nthat type to fix the issue. In addition avoid returning an order\nfrom mb_avg_fragment_size_order() greater than MB_NUM_ORDERS(sb)\nand reduce some useless loops."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "fs/ext4/mballoc.c",
                        "fs/ext4/sysfs.c"
                    ],
                    "versions": [
                        {
                            "version": "7e170922f06b",
                            "lessThan": "677ff4589f15",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "7e170922f06b",
                            "lessThan": "b829687ae122",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "7e170922f06b",
                            "lessThan": "13df4d44a3aa",
                            "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/mballoc.c",
                        "fs/ext4/sysfs.c"
                    ],
                    "versions": [
                        {
                            "version": "6.5",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.5",
                            "status": "unaffected",
                            "versionType": "custom"
                        },
                        {
                            "version": "6.6.36",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "custom"
                        },
                        {
                            "version": "6.9.7",
                            "lessThanOrEqual": "6.9.*",
                            "status": "unaffected",
                            "versionType": "custom"
                        },
                        {
                            "version": "6.10",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/677ff4589f1501578fa903a25bb14831d0607992"
                },
                {
                    "url": "https://git.kernel.org/stable/c/b829687ae1229224262bcabf49accfa2dbf8db06"
                },
                {
                    "url": "https://git.kernel.org/stable/c/13df4d44a3aaabe61cd01d277b6ee23ead2a5206"
                }
            ],
            "title": "ext4: fix slab-out-of-bounds in ext4_mb_find_good_group_avg_frag_lists()",
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                "engine": "bippy-c9c4e1df01b2"
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                    "dateUpdated": "2024-08-02T04:39:55.960Z"
                },
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "https://git.kernel.org/stable/c/677ff4589f1501578fa903a25bb14831d0607992",
                        "tags": [
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            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "id": "CVE-2024-40955",
                                "role": "CISA Coordinator",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "version": "2.0.3",
                                "timestamp": "2024-09-10T17:03:45.786138Z"
                            }
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                "title": "CISA ADP Vulnrichment",
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