[PATCH hyperv-next v4 13/16] Drivers: hv: Free msginfo when the buffer fails to decrypt

[Roman Kisel <romank@linux.microsoft.com>]

The early failure path in __vmbus_establish_gpadl() doesn't deallocate
msginfo if the buffer fails to decrypt.

Fix the leak by breaking out the cleanup code into a separate function
and calling it where required.

Fixes: d4dccf353db80 ("Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM")
Reported-by: Michael Kelly <mkhlinux@outlook.com>
Closes: https://lore.kernel.org/linux-hyperv/SN6PR02MB41573796F9787F67E0E97049D472A@SN6PR02MB4157.namprd02.prod.outlook.com
Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
---
 drivers/hv/channel.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 051eeba800f2..0eb300b940db 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -409,6 +409,25 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
 	return 0;
 }
 
+static void vmbus_free_channel_msginfo(struct vmbus_channel_msginfo *msginfo)
+{
+	unsigned long flags;
+	struct vmbus_channel_msginfo *submsginfo, *tmp;
+
+	if (!msginfo)
+		return;
+
+	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+	list_del(&msginfo->msglistentry);
+	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+	list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
+				 msglistentry) {
+		kfree(submsginfo);
+	}
+
+	kfree(msginfo);
+}
+
 /*
  * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
  *
@@ -428,7 +447,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 	struct vmbus_channel_gpadl_header *gpadlmsg;
 	struct vmbus_channel_gpadl_body *gpadl_body;
 	struct vmbus_channel_msginfo *msginfo = NULL;
-	struct vmbus_channel_msginfo *submsginfo, *tmp;
+	struct vmbus_channel_msginfo *submsginfo;
 	struct list_head *curr;
 	u32 next_gpadl_handle;
 	unsigned long flags;
@@ -458,6 +477,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 			dev_warn(&channel->device_obj->device,
 				"Failed to set host visibility for new GPADL %d.\n",
 				ret);
+			vmbus_free_channel_msginfo(msginfo);
 			return ret;
 		}
 	}
@@ -531,15 +551,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 
 
 cleanup:
-	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
-	list_del(&msginfo->msglistentry);
-	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
-	list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
-				 msglistentry) {
-		kfree(submsginfo);
-	}
-
-	kfree(msginfo);
+	vmbus_free_channel_msginfo(msginfo);
 
 	if (ret) {
 		/*
-- 
2.43.0