1.6 KiB
CVE-2024-56549
Description
In the Linux kernel, the following vulnerability has been resolved:cachefiles: Fix NULL pointer dereference in object->fileAt present, the object->file has the NULL pointer dereference problem inondemand-mode. The root cause is that the allocated fd and object->filelifetime are inconsistent, and the user-space invocation to anon_fd usesobject->file. Following is the process that triggers the issue: [write fd] [umount]cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...)Fix this issue by add an additional reference count to the object->filebefore write/llseek, and decrement after it finished.
POC
Reference
No PoCs from references.