From: Guangming Cao Guangming.Cao@mediatek.com

Because dma-buf.name can be freed in func: "dma_buf_set_name", so, we need to acquire lock first before we read/write dma_buf.name to prevent Use After Free(UAF) issue.

Signed-off-by: Guangming Cao Guangming.Cao@mediatek.com --- drivers/dma-buf/dma-buf.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 511fe0d217a0..9436483a9cfd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -80,7 +80,9 @@ static void dma_buf_release(struct dentry *dentry) dma_resv_fini(dmabuf->resv);

module_put(dmabuf->owner); + spin_lock(&dmabuf->name_lock); kfree(dmabuf->name); + spin_unlock(&dmabuf->name_lock); kfree(dmabuf); }

@@ -1372,6 +1374,8 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) if (ret) goto error_unlock;

+ + spin_lock(&buf_obj->name_lock); seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", buf_obj->size, buf_obj->file->f_flags, buf_obj->file->f_mode, @@ -1379,6 +1383,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) buf_obj->exp_name, file_inode(buf_obj->file)->i_ino, buf_obj->name ?: ""); + spin_unlock(&buf_obj->name_lock);

robj = buf_obj->resv; fence = dma_resv_excl_fence(robj);