DivestOS/Patches/Linux_CVEs/CVE-2017-8262/4.4/0003.patch

From 9ef4ee8e3dfaf4e796bda781826851deebbd89bd Mon Sep 17 00:00:00 2001
From: Sunil Khatri <sunilkh@codeaurora.org>
Date: Fri, 7 Apr 2017 17:00:55 +0530
Subject: msm: kgsl: Fix kgsl memory allocation and free race condition

When allocating userspace memory keep reference to memory
allocation till it is completely initialized and info is sent back
to userspace.

Change-Id: Id72c82bf98c094ecbd4722813c732a998dcbb188
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>
---
 drivers/gpu/msm/kgsl.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/msm/kgsl.c b/drivers/gpu/msm/kgsl.c
index 1de8e21..e49b39f 100644
--- a/drivers/gpu/msm/kgsl.c
+++ b/drivers/gpu/msm/kgsl.c
@@ -260,9 +260,12 @@ kgsl_mem_entry_create(void)
 {
 	struct kgsl_mem_entry *entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 
-	if (entry != NULL)
+	if (entry != NULL) {
 		kref_init(&entry->refcount);
 
+		/* put this ref in the caller functions after init */
+		kref_get(&entry->refcount);
+	}
 	return entry;
 }
 #ifdef CONFIG_DMA_SHARED_BUFFER
@@ -2399,6 +2402,9 @@ long kgsl_ioctl_gpuobj_import(struct kgsl_device_private *dev_priv,
 	trace_kgsl_mem_map(entry, fd);
 
 	kgsl_mem_entry_commit_process(entry);
+
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
 	return 0;
 
 unmap:
@@ -2705,6 +2711,9 @@ long kgsl_ioctl_map_user_mem(struct kgsl_device_private *dev_priv,
 	trace_kgsl_mem_map(entry, param->fd);
 
 	kgsl_mem_entry_commit_process(entry);
+
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
 	return result;
 
 error_attach:
@@ -3143,6 +3152,9 @@ long kgsl_ioctl_gpuobj_alloc(struct kgsl_device_private *dev_priv,
 	param->mmapsize = kgsl_memdesc_footprint(&entry->memdesc);
 	param->id = entry->id;
 
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
+
 	return 0;
 }
 
@@ -3166,6 +3178,9 @@ long kgsl_ioctl_gpumem_alloc(struct kgsl_device_private *dev_priv,
 	param->size = (size_t) entry->memdesc.size;
 	param->flags = (unsigned int) entry->memdesc.flags;
 
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
+
 	return 0;
 }
 
@@ -3189,6 +3204,9 @@ long kgsl_ioctl_gpumem_alloc_id(struct kgsl_device_private *dev_priv,
 	param->mmapsize = (size_t) kgsl_memdesc_footprint(&entry->memdesc);
 	param->gpuaddr = (unsigned long) entry->memdesc.gpuaddr;
 
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
+
 	return 0;
 }
 
@@ -3306,6 +3324,9 @@ long kgsl_ioctl_sparse_phys_alloc(struct kgsl_device_private *dev_priv,
 	trace_sparse_phys_alloc(entry->id, param->size, param->pagesize);
 	kgsl_mem_entry_commit_process(entry);
 
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
+
 	return 0;
 
 err_invalid_pages:
@@ -3385,6 +3406,9 @@ long kgsl_ioctl_sparse_virt_alloc(struct kgsl_device_private *dev_priv,
 	trace_sparse_virt_alloc(entry->id, param->size, param->pagesize);
 	kgsl_mem_entry_commit_process(entry);
 
+	/* put the extra refcount for kgsl_mem_entry_create() */
+	kgsl_mem_entry_put(entry);
+
 	return 0;
 }
 
-- 
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