In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsUpgrade SLES:15.4 kernel-64kb to version 5.14.21-150400.24.122.2 or higher.
Note: Versions mentioned in the description apply only to the upstream kernel-64kb package and not the kernel-64kb package as distributed by SLES.
See How to fix? for SLES:15.4 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
padata: Fix refcnt handling in padata_free_shell()
In a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead to system UAF (Use-After-Free) issues. Due to the lengthy analysis of the pcrypt_aead01 function call, I'll describe the problem scenario using a simplified model:
Suppose there's a user of padata named user_function that adheres to
the padata requirement of calling padata_free_shell after serial()
has been invoked, as demonstrated in the following code:
struct request { struct padata_priv padata; struct completion *done; };void parallel(struct padata_priv *padata) { do_something(); }
void serial(struct padata_priv *padata) { struct request *request = container_of(padata, struct request, padata); complete(request->done); }
void user_function() { DECLARE_COMPLETION(done) padata->parallel = parallel; padata->serial = serial; padata_do_parallel(); wait_for_completion(&done); padata_free_shell(); }
In the corresponding padata.c file, there's the following code:
static void padata_serial_worker(struct work_struct *serial_work) { ... cnt = 0;while (!list_empty(&local_list)) { ... padata->serial(padata); cnt++; } local_bh_enable(); if (refcount_sub_and_test(cnt, &pd->refcnt)) padata_free_pd(pd);
}
Because of the high system load and the accumulation of unexecuted
softirq at this moment, local_bh_enable() in padata takes longer
to execute than usual. Subsequently, when accessing pd->refcnt,
pd has already been released by padata_free_shell(), resulting
in a UAF issue with pd->refcnt.
The fix is straightforward: add refcount_dec_and_test before calling
padata_free_pd in padata_free_shell.