Thread (7 messages) 7 messages, 2 authors, 2021-10-29

Re: [PATCH v2] dma-buf: acquire name lock before read/write dma_buf.name

From: Christian König <christian.koenig@amd.com>
Date: 2021-10-29 07:35:07
Also in: dri-devel, linux-media, linux-mediatek, lkml


Am 29.10.21 um 04:15 schrieb guangming.cao@mediatek.com:
From: Guangming Cao <redacted>

On Fri, 2021-10-08 at 12:24 +0200, Christian König wrote:
quoted
Am 08.10.21 um 09:54 schrieb guangming.cao@mediatek.com:
quoted
From: Guangming Cao <redacted>

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 <redacted>
Reviewed-by: Christian König <christian.koenig@amd.com>

Going to push that upstream if nobody else objects.

Thanks,
Christian.
Just a gentle ping for this patch, please kindly let me know how is it going.
Ah, yes. Thanks for the reminder.

I've just pushed this to drm-misc-fixes.

Christian.
quoted
quoted
---
   drivers/dma-buf/dma-buf.c | 3 +++
   1 file changed, 3 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 511fe0d217a0..a7f6fd13a635 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1372,6 +1372,8 @@ 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-
quoted
f_mode,
@@ -1379,6 +1381,7 @@ 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);
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