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

[Roman Kisel]

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 <mkhli...@outlook.com>
Closes: 
https://lore.kernel.org/linux-hyperv/sn6pr02mb41573796f9787f67e0e97049d4...@sn6pr02mb4157.namprd02.prod.outlook.com
Signed-off-by: Roman Kisel <rom...@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