Re: Linux 2.6.37-rc1 (pcrypt fault)

[Steffen Klassert]

On Wed, Nov 03, 2010 at 02:15:19PM -0700, Randy Dunlap wrote:
> 
> modprobe pcrypt; rmmod pcrypt ==>
> 
> 
> [   76.081639] calling  pcrypt_init+0x0/0x107 [pcrypt] @ 3016
> Nov  3 13:02:15 control kernel: [   76.089883] initcall pcrypt_init+0x0/0x107 [pcrypt] returned 0 after 2476 usecs
> [   76.081639] calling  pcrypt_i
> 
> 
> [   79.940445] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC

Looks like a use after free of the padata instance.
Does the patch below fix it?

Thanks for reporting,

Steffen


Subject: [PATCH] crypto: pcrypt - Fix use after free on padata_free

kobject_put is called from padata_free for the padata kobject.
The kobject's release function frees the padata instance,
so don't call kobject_put for the padata kobject from pcrypt.

Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
---
 crypto/pcrypt.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index de30782..75586f1 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -504,7 +504,6 @@ err:
 
 static void pcrypt_fini_padata(struct padata_pcrypt *pcrypt)
 {
-	kobject_put(&pcrypt->pinst->kobj);
 	free_cpumask_var(pcrypt->cb_cpumask->mask);
 	kfree(pcrypt->cb_cpumask);
 
-- 
1.7.0.4

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