CVE-2024-46738

In the Linux kernel, the following vulnerability has been resolved:

VMCI: Fix use-after-free when removing resource in vmci_resource_remove()

When removing a resource from vmci_resource_table in vmci_resource_remove(), the search is performed using the resource handle by comparing context and resource fields.

It is possible though to create two resources with different types but same handle (same context and resource fields).

When trying to remove one of the resources, vmci_resource_remove() may not remove the intended one, but the object will still be freed as in the case of the datagram type in vmci_datagram_destroy_handle(). vmci_resource_table will still hold a pointer to this freed resource leading to a use-after-free vulnerability.

BUG: KASAN: use-after-free in vmci_handle_is_equal include/linux/vmw_vmci_defs.h:142 [inline] BUG: KASAN: use-after-free in vmci_resource_remove+0x3a1/0x410 drivers/misc/vmw_vmci/vmci_resource.c:147 Read of size 4 at addr ffff88801c16d800 by task syz-executor197/1592 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x82/0xa9 lib/dump_stack.c:106 print_address_description.constprop.0+0x21/0x366 mm/kasan/report.c:239 __kasan_report.cold+0x7f/0x132 mm/kasan/report.c:425 kasan_report+0x38/0x51 mm/kasan/report.c:442 vmci_handle_is_equal include/linux/vmw_vmci_defs.h:142 [inline] vmci_resource_remove+0x3a1/0x410 drivers/misc/vmw_vmci/vmci_resource.c:147 vmci_qp_broker_detach+0x89a/0x11b9 drivers/misc/vmw_vmci/vmci_queue_pair.c:2182 ctx_free_ctx+0x473/0xbe1 drivers/misc/vmw_vmci/vmci_context.c:444 kref_put include/linux/kref.h:65 [inline] vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline] vmci_ctx_destroy+0x170/0x1d6 drivers/misc/vmw_vmci/vmci_context.c:195 vmci_host_close+0x125/0x1ac drivers/misc/vmw_vmci/vmci_host.c:143 __fput+0x261/0xa34 fs/file_table.c:282 task_work_run+0xf0/0x194 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x184/0x189 kernel/entry/common.c:187 exit_to_user_mode_prepare+0x11b/0x123 kernel/entry/common.c:220 __syscall_exit_to_user_mode_work kernel/entry/common.c:302 [inline] syscall_exit_to_user_mode+0x18/0x42 kernel/entry/common.c:313 do_syscall_64+0x41/0x85 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x6e/0x0

This change ensures the type is also checked when removing the resource from vmci_resource_table in vmci_resource_remove().

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/00fe5292f081f8d773e572df8e03bf6e1855fe49
• https://git.kernel.org/stable/c/39e7e593418ccdbd151f2925fa6be1a616d16c96
• https://git.kernel.org/stable/c/48b9a8dabcc3cf5f961b2ebcd8933bf9204babb7
• https://git.kernel.org/stable/c/6c563a29857aa8053b67ee141191f69757f27f6e
• https://git.kernel.org/stable/c/b243d52b5f6f59f9d39e69b191fb3d58b94a43b1
• https://git.kernel.org/stable/c/b9efdf333174468651be40390cbc79c9f55d9cce
• https://git.kernel.org/stable/c/ef5f4d0c5ee22d4f873116fec844ff6edaf3fa7d
• https://git.kernel.org/stable/c/f6365931bf7c07b2b397dbb06a4f6573cc9fae73