CVE-2024-57979

In the Linux kernel, the following vulnerability has been resolved: pps: Fix a use-after-free On a board running ntpd and gpsd, I'm seeing a consistent use-after-free in sys_exit() from gpsd when rebooting: pps pps1: removed ------------[ cut here ]------------ kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called. WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150 CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1 Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kobject_put+0x120/0x150 lr : kobject_put+0x120/0x150 sp : ffffffc0803d3ae0 x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001 x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440 x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600 x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20 x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: kobject_put+0x120/0x150 cdev_put+0x20/0x3c __fput+0x2c4/0x2d8 ____fput+0x1c/0x38 task_work_run+0x70/0xfc do_exit+0x2a0/0x924 do_group_exit+0x34/0x90 get_signal+0x7fc/0x8c0 do_signal+0x128/0x13b4 do_notify_resume+0xdc/0x160 el0_svc+0xd4/0xf8 el0t_64_sync_handler+0x140/0x14c el0t_64_sync+0x190/0x194 ---[ end trace 0000000000000000 ]--- ...followed by more symptoms of corruption, with similar stacks: refcount_t: underflow; use-after-free. kernel BUG at lib/list_debug.c:62! Kernel panic - not syncing: Oops - BUG: Fatal exception This happens because pps_device_destruct() frees the pps_device with the embedded cdev immediately after calling cdev_del(), but, as the comment above cdev_del() notes, fops for previously opened cdevs are still callable even after cdev_del() returns. I think this bug has always been there: I can't explain why it suddenly started happening every time I reboot this particular board. In commit d953e0e837e6 ("pps: Fix a use-after free bug when unregistering a source."), George Spelvin suggested removing the embedded cdev. That seems like the simplest way to fix this, so I've implemented his suggestion, using __register_chrdev() with pps_idr becoming the source of truth for which minor corresponds to which device. But now that pps_idr defines userspace visibility instead of cdev_add(), we need to be sure the pps->dev refcount can't reach zero while userspace can still find it again. So, the idr_remove() call moves to pps_unregister_cdev(), and pps_idr now holds a reference to pps->dev. pps_core: source serial1 got cdev (251:1) <...> pps pps1: removed pps_core: unregistering pps1 pps_core: deallocating pps1
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:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

History

24 Mar 2025, 19:32

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
First Time Linux linux Kernel
Linux
References () https://git.kernel.org/stable/c/1a7735ab2cb9747518a7416fb5929e85442dec62 - () https://git.kernel.org/stable/c/1a7735ab2cb9747518a7416fb5929e85442dec62 - Patch
References () https://git.kernel.org/stable/c/785c78ed0d39d1717cca3ef931d3e51337b5e90e - () https://git.kernel.org/stable/c/785c78ed0d39d1717cca3ef931d3e51337b5e90e - Patch
References () https://git.kernel.org/stable/c/7e5ee3281dc09014367f5112b6d566ba36ea2d49 - () https://git.kernel.org/stable/c/7e5ee3281dc09014367f5112b6d566ba36ea2d49 - Patch
References () https://git.kernel.org/stable/c/85241f7de216f8298f6e48540ea13d7dcd100870 - () https://git.kernel.org/stable/c/85241f7de216f8298f6e48540ea13d7dcd100870 - Patch
References () https://git.kernel.org/stable/c/91932db1d96b2952299ce30c1c693d834d10ace6 - () https://git.kernel.org/stable/c/91932db1d96b2952299ce30c1c693d834d10ace6 - Patch
References () https://git.kernel.org/stable/c/c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 - () https://git.kernel.org/stable/c/c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 - Patch
References () https://git.kernel.org/stable/c/c79a39dc8d060b9e64e8b0fa9d245d44befeefbe - () https://git.kernel.org/stable/c/c79a39dc8d060b9e64e8b0fa9d245d44befeefbe - Patch
References () https://git.kernel.org/stable/c/cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64 - () https://git.kernel.org/stable/c/cd3bbcb6b3a7caa5ce67de76723b6d8531fb7f64 - Patch

13 Mar 2025, 13:15

Type Values Removed Values Added
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: pps: Se corrige un error de use after free. En una placa que ejecuta ntpd y gpsd, veo un error de use after free constante en sys_exit() desde gpsd al reiniciar: pps pps1: eliminado ------------[ cortar aquí ]------------ kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called. WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150 CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1 Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : kobject_put+0x120/0x150 lr : kobject_put+0x120/0x150 sp : ffffffc0803d3ae0 x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001 x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440 x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600 x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20 x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: kobject_put+0x120/0x150 cdev_put+0x20/0x3c __fput+0x2c4/0x2d8 ____fput+0x1c/0x38 task_work_run+0x70/0xfc do_exit+0x2a0/0x924 do_group_exit+0x34/0x90 get_signal+0x7fc/0x8c0 do_signal+0x128/0x13b4 do_notify_resume+0xdc/0x160 el0_svc+0xd4/0xf8 el0t_64_sync_handler+0x140/0x14c el0t_64_sync+0x190/0x194 ---[ end trace 0000000000000000 ]--- ...seguido de más síntomas de corrupción, con pilas similares: refcount_t: desbordamiento; use after free. ¡ERROR del kernel en lib/list_debug.c:62! Pánico del kernel - no sincroniza: Vaya - ERROR: Excepción fatal Esto sucede porque pps_device_destruct() libera el pps_device con el cdev integrado inmediatamente después de llamar a cdev_del(), pero, como señala el comentario anterior a cdev_del(), los fops para cdevs abiertos previamente aún se pueden llamar incluso después de que cdev_del() regrese. Creo que este error siempre ha estado ahí: no puedo explicar por qué de repente empezó a suceder cada vez que reinicio esta placa en particular. En el commit d953e0e837e6 ("pps: Arreglar un error de use after free al anular el registro de una fuente"), George Spelvin sugirió eliminar el cdev integrado. Esa parece la forma más sencilla de solucionarlo, así que he implementado su sugerencia, utilizando __register_chrdev() con pps_idr convirtiéndose en la fuente de verdad para la cual el menor corresponde a qué dispositivo. Pero ahora que pps_idr define la visibilidad del espacio de usuario en lugar de cdev_add(), debemos asegurarnos de que el recuento de referencias pps-&gt;dev no pueda llegar a cero mientras que el espacio de usuario aún pueda encontrarlo de nuevo. Entonces, la llamada idr_remove() se mueve a pps_unregister_cdev(), y pps_idr ahora contiene una referencia a pps-&gt;dev. pps_core: la fuente serial1 obtuvo cdev (251:1) &lt;...&gt; pps pps1: eliminado pps_core: anulando el registro de pps1 pps_core: desasignando pps1
References
  • () https://git.kernel.org/stable/c/1a7735ab2cb9747518a7416fb5929e85442dec62 -
  • () https://git.kernel.org/stable/c/785c78ed0d39d1717cca3ef931d3e51337b5e90e -
  • () https://git.kernel.org/stable/c/c4041b6b0a7a3def8cf3f3d6120ff337bc4c40f7 -

27 Feb 2025, 19:15

Type Values Removed Values Added
CWE CWE-416
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 7.8

27 Feb 2025, 02:15

Type Values Removed Values Added
New CVE

Information

Published : 2025-02-27 02:15

Updated : 2025-03-24 19:32


NVD link : CVE-2024-57979

Mitre link : CVE-2024-57979

CVE.ORG link : CVE-2024-57979


JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-416

Use After Free