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Vulnerability Change Records for CVE-2024-56549

Change History

New CVE Received from kernel.org 12/27/2024 9:15:34 AM

Action Type Old Value New Value
Added Description

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

cachefiles: Fix NULL pointer dereference in object->file

At present, the object->file has the NULL pointer dereference problem in
ondemand-mode. The root cause is that the allocated fd and object->file
lifetime are inconsistent, and the user-space invocation to anon_fd uses
object->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->file
before write/llseek, and decrement after it finished.
Added Reference

								
							
							
						
https://git.kernel.org/stable/c/31ad74b20227ce6b40910ff78b1c604e42975cf1
Added Reference

								
							
							
						
https://git.kernel.org/stable/c/9582c7664103c9043e80a78f5c382aa6bdd67418
Added Reference

								
							
							
						
https://git.kernel.org/stable/c/f98770440c9bc468e2fd878212ec9526dbe08293