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https://github.com/fkie-cad/nvd-json-data-feeds.git
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29 lines
2.9 KiB
JSON
29 lines
2.9 KiB
JSON
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{
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"id": "CVE-2024-40955",
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"published": "2024-07-12T13:15:17.697",
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"lastModified": "2024-07-12T13:15:17.697",
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"vulnStatus": "Received",
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"cveTags": [],
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"descriptions": [
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{
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"lang": "en",
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"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."
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}
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],
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"metrics": {},
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/13df4d44a3aaabe61cd01d277b6ee23ead2a5206",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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},
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{
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"url": "https://git.kernel.org/stable/c/677ff4589f1501578fa903a25bb14831d0607992",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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},
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{
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"url": "https://git.kernel.org/stable/c/b829687ae1229224262bcabf49accfa2dbf8db06",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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}
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]
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}
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