CVE-2024-42305

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2024-42305
In the Linux kernel, the following vulnerability has been resolved: ext4: check dot and dotdot of dx_root before making dir indexed Syzbot reports a issue as follows: ============================================ BUG: unable to handle page fault for address: ffffed11022e24fe PGD 23ffee067 P4D 23ffee067 PUD 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0 Call Trace: <TASK> make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341 ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451 ext4_rename fs/ext4/namei.c:3936 [inline] ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 [...] ============================================ The immediate cause of this problem is that there is only one valid dentry for the block to be split during do_split, so split==0 results in out of bounds accesses to the map triggering the issue. do_split unsigned split dx_make_map count = 1 split = count/2 = 0; continued = hash2 == map[split - 1].hash; ---> map[4294967295] The maximum length of a filename is 255 and the minimum block size is 1024, so it is always guaranteed that the number of entries is greater than or equal to 2 when do_split() is called. But syzbot's crafted image has no dot and dotdot in dir, and the dentry distribution in dirblock is as follows: bus dentry1 hole dentry2 free |xx--|xx-------------|...............|xx-------------|...............| 0 12 (8+248)=256 268 256 524 (8+256)=264 788 236 1024 So when renaming dentry1 increases its name_len length by 1, neither hole nor free is sufficient to hold the new dentry, and make_indexed_dir() is called. In make_indexed_dir() it is assumed that the first two entries of the dirblock must be dot and dotdot, so bus and dentry1 are left in dx_root because they are treated as dot and dotdot, and only dentry2 is moved to the new leaf block. That's why count is equal to 1. Therefore add the ext4_check_dx_root() helper function to add more sanity checks to dot and dotdot before starting the conversion to avoid the above issue.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8 Patch
https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa Patch
https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7 Patch
https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a Patch
https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2 Patch
https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c Patch
https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db Patch
https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5 Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc6:*:*:*:*:*:*
History

29 Sep 2025, 15:11

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:2.6.19:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.19:-:*:*:*:*:*:*
References () https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8 - () https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8 - Patch
References () https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa - () https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa - Patch
References () https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7 - () https://git.kernel.org/stable/c/50ea741def587a64e08879ce6c6a30131f7111e7 - Patch
References () https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a - () https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a - Patch
References () https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2 - () https://git.kernel.org/stable/c/9d241b7a39af192d1bb422714a458982c7cc67a2 - Patch
References () https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c - () https://git.kernel.org/stable/c/abb411ac991810c0bcbe51c2e76d2502bf611b5c - Patch
References () https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db - () https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db - Patch
References () https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5 - () https://git.kernel.org/stable/c/cdd345321699042ece4a9d2e70754d2397d378c5 - Patch
CWE CWE-125
First Time Linux
Linux linux Kernel
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5

19 Aug 2024, 12:59

Type Values Removed Values Added
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: verifique el punto y el punto de dx_root antes de indexar el directorio Syzbot informa un problema de la siguiente manera: =================== ========================= ERROR: no se puede manejar el error de página para la dirección: ffffed11022e24fe PGD 23ffee067 P4D 23ffee067 PUD 0 Ups: Ups: 0000 [#1 ] PREEMPT SMP KASAN PTI CPU: 0 PID: 5079 Comm: syz-executor306 No contaminado 6.10.0-rc5-g55027e689933 #0 Seguimiento de llamada: make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341 ext4_add_entry+0x222 un /0x25d0 fs/ext4/namei.c:2451 ext4_rename fs/ext4/namei.c:3936 [en línea] text4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 [...] ======= ====================================== La causa inmediata de este problema es que sólo hay una válida dentry para que el bloque se divida durante do_split, por lo que split==0 da como resultado accesos fuera de los límites al mapa que desencadenan el problema. do_split división sin signo dx_make_map recuento = 1 división = recuento/2 = 0; continúa = hash2 == mapa[dividido - 1].hash; ---&gt; map[4294967295] La longitud máxima de un nombre de archivo es 255 y el tamaño mínimo de bloque es 1024, por lo que siempre se garantiza que el número de entradas sea mayor o igual a 2 cuando se llama a do_split(). Pero la imagen manipulada por syzbot no tiene punto ni puntopunto en el directorio, y la distribución de dentry en dirblock es la siguiente: bus dentry1 agujero dentry2 gratis |xx--|xx-------------|... ............|xx-------------|...............| 0 12 (8+248)=256 268 256 524 (8+256)=264 788 236 1024 Entonces, cuando se cambia el nombre de dentry1 se aumenta la longitud de name_len en 1, ni el agujero ni el espacio libre son suficientes para contener el nuevo dentry, y make_indexed_dir() es llamado. En make_indexed_dir() se supone que las dos primeras entradas del bloque de directorios deben ser punto y puntopunto, por lo que bus y dentry1 se dejan en dx_root porque se tratan como punto y puntodot, y solo dentry2 se mueve al nuevo bloque de hoja. Es por eso que el recuento es igual a 1. Por lo tanto, agregue la función auxiliar ext4_check_dx_root() para agregar más controles de cordura a los puntos y puntos antes de comenzar la conversión para evitar el problema anterior.

19 Aug 2024, 05:15

Type Values Removed Values Added
References
  • () https://git.kernel.org/stable/c/19e13b4d7f0303186fcc891aba8d0de7c8fdbda8 -
  • () https://git.kernel.org/stable/c/42d420517072028fb0eb852c358056b7717ba5aa -
  • () https://git.kernel.org/stable/c/8afe06ed3be7a874b3cd82ef5f8959aca8d6429a -
  • () https://git.kernel.org/stable/c/b80575ffa98b5bb3a5d4d392bfe4c2e03e9557db -

17 Aug 2024, 09:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-08-17 09:15

Updated : 2025-09-29 15:11

NVD link : CVE-2024-42305

Mitre link : CVE-2024-42305

CVE.ORG link : CVE-2024-42305

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-125

Out-of-bounds Read