CVE-2024-49882

{"id": "CVE-2024-49882", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "published": "2024-10-21T18:15:10.790", "references": [{"url": "https://git.kernel.org/stable/c/230ee0535d01478bad9a3037292043f39b9be10b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/32bbb59e3f18facd7201bef110010bf35819b8c3", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/68a69cf60660c73990c1875f94a5551600b04775", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7633407ca4ab8be2916ab214eb44ccebc6a50e1a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/78bbc3d15b6f443acb26e94418c445bac940d414", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b6c29c8f3d7cb67b505f3b2f6c242d52298d1f2e", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d4574bda63906bf69660e001470bfe1a0ac524ae", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dcaa6c31134c0f515600111c38ed7750003e1b9c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/f9fd47c9d9548f9e47fa60098eab99dde175401d", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-415"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix double brelse() the buffer of the extents path\n\nIn ext4_ext_try_to_merge_up(), set path[1].p_bh to NULL after it has been\nreleased, otherwise it may be released twice. An example of what triggers\nthis is as follows:\n\n split2 map split1\n|--------|-------|--------|\n\next4_ext_map_blocks\n ext4_ext_handle_unwritten_extents\n ext4_split_convert_extents\n // path->p_depth == 0\n ext4_split_extent\n // 1. do split1\n ext4_split_extent_at\n |ext4_ext_insert_extent\n | ext4_ext_create_new_leaf\n | ext4_ext_grow_indepth\n | le16_add_cpu(&neh->eh_depth, 1)\n | ext4_find_extent\n | // return -ENOMEM\n |// get error and try zeroout\n |path = ext4_find_extent\n | path->p_depth = 1\n |ext4_ext_try_to_merge\n | ext4_ext_try_to_merge_up\n | path->p_depth = 0\n | brelse(path[1].p_bh) ---> not set to NULL here\n |// zeroout success\n // 2. update path\n ext4_find_extent\n // 3. do split2\n ext4_split_extent_at\n ext4_ext_insert_extent\n ext4_ext_create_new_leaf\n ext4_ext_grow_indepth\n le16_add_cpu(&neh->eh_depth, 1)\n ext4_find_extent\n path[0].p_bh = NULL;\n path->p_depth = 1\n read_extent_tree_block ---> return err\n // path[1].p_bh is still the old value\n ext4_free_ext_path\n ext4_ext_drop_refs\n // path->p_depth == 1\n brelse(path[1].p_bh) ---> brelse a buffer twice\n\nFinally got the following WARRNING when removing the buffer from lru:\n\n============================================\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 72 at fs/buffer.c:1241 __brelse+0x58/0x90\nCPU: 2 PID: 72 Comm: kworker/u19:1 Not tainted 6.9.0-dirty #716\nRIP: 0010:__brelse+0x58/0x90\nCall Trace:\n <TASK>\n __find_get_block+0x6e7/0x810\n bdev_getblk+0x2b/0x480\n __ext4_get_inode_loc+0x48a/0x1240\n ext4_get_inode_loc+0xb2/0x150\n ext4_reserve_inode_write+0xb7/0x230\n __ext4_mark_inode_dirty+0x144/0x6a0\n ext4_ext_insert_extent+0x9c8/0x3230\n ext4_ext_map_blocks+0xf45/0x2dc0\n ext4_map_blocks+0x724/0x1700\n ext4_do_writepages+0x12d6/0x2a70\n[...]\n============================================"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: corregir el doble brelse() del b\u00fafer de la ruta de las extensiones En ext4_ext_try_to_merge_up(), establezca path[1].p_bh en NULL despu\u00e9s de que se haya liberado, de lo contrario, puede liberarse dos veces. Un ejemplo de lo que desencadena esto es el siguiente: split2 map split1 |--------|-------|--------| ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_split_convert_extents // path-&gt;p_depth == 0 ext4_split_extent // 1. hacer split1 ext4_split_extent_at |ext4_ext_insert_extent | ext4_ext_create_new_leaf | ext4_ext_grow_indepth | le16_add_cpu(&amp;neh-&gt;eh_depth, 1) | ext4_find_extent | // devuelve -ENOMEM |// obtiene el error e intenta poner a cero |path = ext4_find_extent | path-&gt;p_depth = 1 |ext4_ext_try_to_merge | ext4_ext_try_to_merge_up | path-&gt;p_depth = 0 | brelse(path[1].p_bh) ---&gt; no establecido en NULL aqu\u00ed |// puesta a cero exitosa // 2. actualizar ruta ext4_find_extent // 3. hacer split2 ext4_split_extent_at ext4_ext_insert_extent ext4_ext_create_new_leaf ext4_ext_grow_indepth le16_add_cpu(&amp;neh-&gt;eh_depth, 1) ext4_find_extent path[0].p_bh = NULL; path-&gt;p_depth = 1 read_extent_tree_block ---&gt; return err // path[1].p_bh sigue siendo el valor anterior ext4_free_ext_path ext4_ext_drop_refs // path-&gt;p_depth == 1 brelse(path[1].p_bh) ---&gt; brelse un buffer dos veces Finalmente obtuve la siguiente ADVERTENCIA al eliminar el buffer de lru: =============================================== VFS: brelse: Intentando liberar b\u00fafer libre ADVERTENCIA: CPU: 2 PID: 72 en fs/buffer.c:1241 __brelse+0x58/0x90 CPU: 2 PID: 72 Comm: kworker/u19:1 No contaminado 6.9.0-dirty #716 RIP: 0010:__brelse+0x58/0x90 Seguimiento de llamadas: __find_get_block+0x6e7/0x810 bdev_getblk+0x2b/0x480 __ext4_get_inode_loc+0x48a/0x1240 ext4_get_inode_loc+0xb2/0x150 ext4_reserve_inode_write+0xb7/0x230 __ext4_mark_inode_dirty+0x144/0x6a0 ext4_ext_insert_extent+0x9c8/0x3230 ext4_ext_map_blocks+0xf45/0x2dc0 ext4_map_blocks+0x724/0x1700 ext4_do_writepages+0x12d6/0x2a70 [...] ============================================"}], "lastModified": "2024-11-08T16:15:30.123", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3B73A13A-D7BE-4035-BEF2-2821D9D5CB6D", "versionEndExcluding": "5.10.227", "versionStartIncluding": "3.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4D51C05D-455B-4D8D-89E7-A58E140B864C", "versionEndExcluding": "5.15.168", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D01BD22E-ACD1-4618-9D01-6116570BE1EE", "versionEndExcluding": "6.1.113", "versionStartIncluding": "5.16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E90B9576-56C4-47BC-AAB0-C5B2D438F5D0", "versionEndExcluding": "6.6.55", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4C16BCE0-FFA0-4599-BE0A-1FD65101C021", "versionEndExcluding": "6.10.14", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "54D9C704-D679-41A7-9C40-10A6B1E7FFE9", "versionEndExcluding": "6.11.3", "versionStartIncluding": "6.11"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}