[PATCH v2 1/2] opal: Fix the overflow of message notifiers head array

[PATCH v2 1/2] opal: Fix the overflow of message notifiers head array

[Neelesh Gupta]

Fixes the condition check of incoming message type which can
otherwise shoot beyond the message notifiers head array.

Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/opal.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index f10b9ec..2651e22 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -305,16 +305,12 @@ void opal_notifier_disable(void)
 int opal_message_notifier_register(enum OpalMessageType msg_type,
 					struct notifier_block *nb)
 {
-	if (!nb) {
-		pr_warning("%s: Invalid argument (%p)\n",
-			   __func__, nb);
-		return -EINVAL;
-	}
-	if (msg_type > OPAL_MSG_TYPE_MAX) {
-		pr_warning("%s: Invalid message type argument (%d)\n",
+	if (!nb || msg_type >= OPAL_MSG_TYPE_MAX) {
+		pr_warning("%s: Invalid arguments, msg_type:%d\n",
 			   __func__, msg_type);
 		return -EINVAL;
 	}
+
 	return atomic_notifier_chain_register(
 				&opal_msg_notifier_head[msg_type], nb);
 }
@@ -351,7 +347,7 @@ static void opal_handle_message(void)
 	type = be32_to_cpu(msg.msg_type);
 
 	/* Sanity check */
-	if (type > OPAL_MSG_TYPE_MAX) {
+	if (type >= OPAL_MSG_TYPE_MAX) {
 		pr_warning("%s: Unknown message type: %u\n", __func__, type);
 		return;
 	}

[PATCH 2/2] opal: Add message notifier unregister function

[Neelesh Gupta]

Provide an unregister interface for the opal message notifiers
to be called when not needed like during driver unload/remove.

Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/opal.h       |    2 ++
 arch/powerpc/platforms/powernv/opal.c |    7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index eb95b67..70eb45f 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -940,6 +940,8 @@ extern int opal_notifier_unregister(struct notifier_block *nb);
 
 extern int opal_message_notifier_register(enum OpalMessageType msg_type,
 						struct notifier_block *nb);
+extern int opal_message_notifier_unregister(enum OpalMessageType msg_type,
+					    struct notifier_block *nb);
 extern void opal_notifier_enable(void);
 extern void opal_notifier_disable(void);
 extern void opal_notifier_update_evt(uint64_t evt_mask, uint64_t evt_val);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 2651e22..6c108ce 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -315,6 +315,13 @@ int opal_message_notifier_register(enum OpalMessageType msg_type,
 				&opal_msg_notifier_head[msg_type], nb);
 }
 
+int opal_message_notifier_unregister(enum OpalMessageType msg_type,
+				     struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(
+			&opal_msg_notifier_head[msg_type], nb);
+}
+
 static void opal_message_do_notify(uint32_t msg_type, void *msg)
 {
 	/* notify subscribers */

Re: [PATCH 2/2] opal: Add message notifier unregister function

[Anshuman Khandual]

On 02/11/2015 11:57 AM, Neelesh Gupta wrote:
> Provide an unregister interface for the opal message notifiers
> to be called when not needed like during driver unload/remove.

Why only for unload/remove, you can also use it in cases where you need
to abort because of any other error soon after successful registration
for an OPAL message. 

Re: [PATCH 2/2] opal: Add message notifier unregister function

[Neelesh Gupta]

On 02/11/2015 04:27 PM, Anshuman Khandual wrote:
> On 02/11/2015 11:57 AM, Neelesh Gupta wrote:
>> Provide an unregister interface for the opal message notifiers
>> to be called when not needed like during driver unload/remove.
> Why only for unload/remove, you can also use it in cases where you need
> to abort because of any other error soon after successful registration
> for an OPAL message.

I didn't mean *only* driver unload/remove.. gave a simple use case of why do
we need this change.

Neelesh.

>

Re: [PATCH v2 1/2] opal: Fix the overflow of message notifiers head array

[Anshuman Khandual]

On 02/11/2015 11:57 AM, Neelesh Gupta wrote:
> Fixes the condition check of incoming message type which can
> otherwise shoot beyond the message notifiers head array.
> 
> Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
> Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>