[Mesa-dev] [PATCH] glsl/blob: clear padding bytes

[Grazvydas Ignotas]

Since blob is intended for serializing data, it's not a good idea to
leave padding holes with uninitialized data, which may leak heap
contents and hurt compression if the blob is later compressed, like
done by shader cache. Clear it.

Signed-off-by: Grazvydas Ignotas <notasas at gmail.com>
---
I don't know why blob bothers with aligning at all, maybe it's better
to just get rid of it and replace *(uint *) reads with memcpy?

 src/compiler/glsl/blob.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/compiler/glsl/blob.c b/src/compiler/glsl/blob.c
index dd4341b..a7a5e65 100644
--- a/src/compiler/glsl/blob.c
+++ b/src/compiler/glsl/blob.c
@@ -70,10 +70,13 @@ align_blob(struct blob *blob, size_t alignment)
 {
    const size_t new_size = ALIGN(blob->size, alignment);
 
-   if (! grow_to_fit (blob, new_size - blob->size))
-      return false;
+   if (blob->size < new_size) {
+      if (! grow_to_fit(blob, new_size - blob->size))
+         return false;
 
-   blob->size = new_size;
+      memset(blob->data + blob->size, 0, new_size - blob->size);
+      blob->size = new_size;
+   }
 
    return true;
 }
-- 
2.7.4