Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1363556 > unrolled thread

[PATCH] x86/mce: Avoid using object after free in genpool.

Back to article view | Back to linux.kernel

Contents

  [PATCH] x86/mce: Avoid using object after free in genpool. Tony Luck <tony.luck@intel.com> - 2016-03-23 18:00 +0100
    Re: [PATCH] x86/mce: Avoid using object after free in genpool. Borislav Petkov <bp@alien8.de> - 2016-03-23 18:40 +0100
      RE: [PATCH] x86/mce: Avoid using object after free in genpool. "Luck, Tony" <tony.luck@intel.com> - 2016-03-23 21:50 +0100

#1363556 — [PATCH] x86/mce: Avoid using object after free in genpool.

When we loop over all queued machine check error records to pass
them to the registered notifiers we use llist_for_each_entry().
But the loop calls gen_pool_free() for the entry in the body of
the loop - and then the iterator looks at node->next after the
free.

Use llist_for_each_entry_safe() instead.

Cc: stable@vger.kernel.org
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 arch/x86/kernel/cpu/mcheck/mce-genpool.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce-genpool.c b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
index 0a850100c594..2658e2af74ec 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
@@ -29,7 +29,7 @@ static char gen_pool_buf[MCE_POOLSZ];
 void mce_gen_pool_process(void)
 {
 	struct llist_node *head;
-	struct mce_evt_llist *node;
+	struct mce_evt_llist *node, *tmp;
 	struct mce *mce;
 
 	head = llist_del_all(&mce_event_llist);
@@ -37,7 +37,7 @@ void mce_gen_pool_process(void)
 		return;
 
 	head = llist_reverse_order(head);
-	llist_for_each_entry(node, head, llnode) {
+	llist_for_each_entry_safe(node, tmp, head, llnode) {
 		mce = &node->mce;
 		atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
 		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
-- 
2.5.0

[toc] | [next] | [standalone]

#1363578

On Wed, Mar 23, 2016 at 09:14:40AM -0700, Tony Luck wrote:
> When we loop over all queued machine check error records to pass
> them to the registered notifiers we use llist_for_each_entry().
> But the loop calls gen_pool_free() for the entry in the body of
> the loop - and then the iterator looks at node->next after the
> free.
> 
> Use llist_for_each_entry_safe() instead.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
>  arch/x86/kernel/cpu/mcheck/mce-genpool.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce-genpool.c b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
> index 0a850100c594..2658e2af74ec 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
> @@ -29,7 +29,7 @@ static char gen_pool_buf[MCE_POOLSZ];
>  void mce_gen_pool_process(void)
>  {
>  	struct llist_node *head;
> -	struct mce_evt_llist *node;
> +	struct mce_evt_llist *node, *tmp;
>  	struct mce *mce;
>  
>  	head = llist_del_all(&mce_event_llist);
> @@ -37,7 +37,7 @@ void mce_gen_pool_process(void)
>  		return;
>  
>  	head = llist_reverse_order(head);
> -	llist_for_each_entry(node, head, llnode) {
> +	llist_for_each_entry_safe(node, tmp, head, llnode) {
>  		mce = &node->mce;
>  		atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
>  		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
> -- 

Acked-by: Borislav Petkov <bp@suse.de>

I have a couple more RAS patches for tip, want me to pick that one up
too? I'm going to send my pile to tip guys after -rc1 is out.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

[toc] | [prev] | [next] | [standalone]

#1363679

> Acked-by: Borislav Petkov <bp@suse.de>

Thanks

> I have a couple more RAS patches for tip, want me to pick that one up
> too? I'm going to send my pile to tip guys after -rc1 is out.

Yes please ... throw this one on the pile.

-Tony

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web