Module: libav
Branch: master
Commit: 3d040513a1de4797a4f81dde4984395f51db76b7
Author: Aaron Levinson <alevi...@aracnet.com>
Committer: Anton Khirnov <an...@khirnov.net>
Date: Tue May 16 14:23:27 2017 -0700
avutil/hwcontext_dxva2: Don't improperly free IDirect3DSurface9 objects
Add dxva2_pool_release_dummy() and use it in call to
av_buffer_create() in dxva2_pool_alloc().
Prior to this change, av_buffer_create() was called with NULL for the
third argument, which indicates that av_buffer_default_free() should
be used to free the buffer's data. Eventually, it gets to
buffer_pool_free() and calls buf->free() on a surface object (which is
av_buffer_default_free()).
This can result in a crash when the debug version of the C-runtime is
used on Windows. While it doesn't appear to result in a crash when
the release version of the C-runtime is used on Windows, it likely
results in memory corruption, since av_free() is being called on
memory that was allocated using
IDirectXVideoAccelerationService::CreateSurface().
Signed-off-by: Aaron Levinson <alevi...@aracnet.com>
Reviewed-by: wm4 <nfx...@googlemail.com>
Reviewed-by: Steven Liu <lingjiujia...@gmail.com>
Reviewed-by: Mark Thompson <s...@jkqxz.net>
Signed-off-by: Anton Khirnov <an...@khirnov.net>
---
libavutil/hwcontext_dxva2.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/libavutil/hwcontext_dxva2.c b/libavutil/hwcontext_dxva2.c
index 3790bed..d1b19ab 100644
--- a/libavutil/hwcontext_dxva2.c
+++ b/libavutil/hwcontext_dxva2.c
@@ -119,6 +119,13 @@ static void dxva2_frames_uninit(AVHWFramesContext *ctx)
}
}
+static void dxva2_pool_release_dummy(void *opaque, uint8_t *data)
+{
+ // important not to free anything here--data is a surface object
+ // associated with the call to CreateSurface(), and these surfaces are
+ // released in dxva2_frames_uninit()
+}
+
static AVBufferRef *dxva2_pool_alloc(void *opaque, int size)
{
AVHWFramesContext *ctx = (AVHWFramesContext*)opaque;
@@ -128,7 +135,7 @@ static AVBufferRef *dxva2_pool_alloc(void *opaque, int size)
if (s->nb_surfaces_used < hwctx->nb_surfaces) {
s->nb_surfaces_used++;
return
av_buffer_create((uint8_t*)s->surfaces_internal[s->nb_surfaces_used - 1],
- sizeof(*hwctx->surfaces), NULL, 0, 0);
+ sizeof(*hwctx->surfaces),
dxva2_pool_release_dummy, 0, 0);
}
return NULL;
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