GHSA-PVGC-VPGW-88MQ
Vulnerability from github – Published: 2024-10-21 18:30 – Updated: 2025-11-04 00:31In the Linux kernel, the following vulnerability has been resolved:
ext4: update orig_path in ext4_find_extent()
In ext4_find_extent(), if the path is not big enough, we free it and set orig_path to NULL. But after reallocating and successfully initializing the path, we don't update orig_path, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example:
ext4_split_extent path = ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(ppath = NULL) path = ppath; ex = path[depth].p_ext; // NULL pointer dereference!
================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Call Trace: ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ==================================================================
Therefore, orig_path is updated when the extent lookup succeeds, so that the caller can safely use path or ppath.
{
"affected": [],
"aliases": [
"CVE-2024-49881"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-10-21T18:15:10Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: update orig_path in ext4_find_extent()\n\nIn ext4_find_extent(), if the path is not big enough, we free it and set\n*orig_path to NULL. But after reallocating and successfully initializing\nthe path, we don\u0027t update *orig_path, in which case the caller gets a\nvalid path but a NULL ppath, and this may cause a NULL pointer dereference\nor a path memory leak. For example:\n\next4_split_extent\n path = *ppath = 2000\n ext4_find_extent\n if (depth \u003e path[0].p_maxdepth)\n kfree(path = 2000);\n *orig_path = path = NULL;\n path = kcalloc() = 3000\n ext4_split_extent_at(*ppath = NULL)\n path = *ppath;\n ex = path[depth].p_ext;\n // NULL pointer dereference!\n\n==================================================================\nBUG: kernel NULL pointer dereference, address: 0000000000000010\nCPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847\nRIP: 0010:ext4_split_extent_at+0x6d/0x560\nCall Trace:\n \u003cTASK\u003e\n ext4_split_extent.isra.0+0xcb/0x1b0\n ext4_ext_convert_to_initialized+0x168/0x6c0\n ext4_ext_handle_unwritten_extents+0x325/0x4d0\n ext4_ext_map_blocks+0x520/0xdb0\n ext4_map_blocks+0x2b0/0x690\n ext4_iomap_begin+0x20e/0x2c0\n[...]\n==================================================================\n\nTherefore, *orig_path is updated when the extent lookup succeeds, so that\nthe caller can safely use path or *ppath.",
"id": "GHSA-pvgc-vpgw-88mq",
"modified": "2025-11-04T00:31:40Z",
"published": "2024-10-21T18:30:56Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-49881"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/11b230100d6801c014fab2afabc8bdea304c1b96"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5b4b2dcace35f618fe361a87bae6f0d13af31bc1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6766937d0327000ac1b87c97bbecdd28b0dd6599"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6801ed1298204d16a38571091e31178bfdc3c679"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a9fcb1717d75061d3653ed69365c8d45331815cd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b63481b3a388ee2df9e295f97273226140422a42"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ec0c0beb9b777cdd1edd7df9b36e0f3e67e2bdff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f55ecc58d07a6c1f6d6d5b5af125c25f8da0bda2"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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