{
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    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2024-49880",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix off by one issue in alloc_flex_gd()\n\nWesley reported an issue:\n\n==================================================================\nEXT4-fs (dm-5): resizing filesystem from 7168 to 786432 blocks\n------------[ cut here ]------------\nkernel BUG at fs/ext4/resize.c:324!\nCPU: 9 UID: 0 PID: 3576 Comm: resize2fs Not tainted 6.11.0+ #27\nRIP: 0010:ext4_resize_fs+0x1212/0x12d0\nCall Trace:\n __ext4_ioctl+0x4e0/0x1800\n ext4_ioctl+0x12/0x20\n __x64_sys_ioctl+0x99/0xd0\n x64_sys_call+0x1206/0x20d0\n do_syscall_64+0x72/0x110\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n==================================================================\n\nWhile reviewing the patch, Honza found that when adjusting resize_bg in\nalloc_flex_gd(), it was possible for flex_gd->resize_bg to be bigger than\nflexbg_size.\n\nThe reproduction of the problem requires the following:\n\n o_group = flexbg_size * 2 * n;\n o_size = (o_group + 1) * group_size;\n n_group: [o_group + flexbg_size, o_group + flexbg_size * 2)\n o_size = (n_group + 1) * group_size;\n\nTake n=0,flexbg_size=16 as an example:\n\n              last:15\n|o---------------|--------------n-|\no_group:0    resize to      n_group:30\n\nThe corresponding reproducer is:\n\nimg=test.img\nrm -f $img\ntruncate -s 600M $img\nmkfs.ext4 -F $img -b 1024 -G 16 8M\ndev=`losetup -f --show $img`\nmkdir -p /tmp/test\nmount $dev /tmp/test\nresize2fs $dev 248M\n\nDelete the problematic plus 1 to fix the issue, and add a WARN_ON_ONCE()\nto prevent the issue from happening again.\n\n[ Note: another reproucer which this commit fixes is:\n\n  img=test.img\n  rm -f $img\n  truncate -s 25MiB $img\n  mkfs.ext4 -b 4096 -E nodiscard,lazy_itable_init=0,lazy_journal_init=0 $img\n  truncate -s 3GiB $img\n  dev=`losetup -f --show $img`\n  mkdir -p /tmp/test\n  mount $dev /tmp/test\n  resize2fs $dev 3G\n  umount $dev\n  losetup -d $dev\n\n  -- TYT ]"
            }
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                        "value": "n/a"
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                    "product": {
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                                "product_name": "Linux",
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                                            "version_value": "0d80d2b8bf61"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
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                                                        "version": "6.8",
                                                        "status": "affected"
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                                                        "lessThanOrEqual": "6.11.*",
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