[PATCH v2 05/17] vdso: Avoid call to memset() by getrandom

[Christophe Leroy]

With the current implementation, __cvdso_getrandom_data() calls
memset(), which is unexpected in the VDSO.

Rewrite opaque data initialisation to avoid memset().

Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
---
 lib/vdso/getrandom.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
index cab153c5f9be..4a56f45141b4 100644
--- a/lib/vdso/getrandom.c
+++ b/lib/vdso/getrandom.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/minmax.h>
+#include <linux/array_size.h>
 #include <vdso/datapage.h>
 #include <vdso/getrandom.h>
 #include <vdso/unaligned.h>
@@ -74,11 +75,15 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
 	u32 counter[2] = { 0 };
 
 	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags)) {
-		*(struct vgetrandom_opaque_params *)opaque_state = (struct vgetrandom_opaque_params) {
-			.size_of_opaque_state = sizeof(*state),
-			.mmap_prot = PROT_READ | PROT_WRITE,
-			.mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS
-		};
+		struct vgetrandom_opaque_params *params = opaque_state;
+		int i;
+
+		params->size_of_opaque_state = sizeof(*state);
+		params->mmap_prot = PROT_READ | PROT_WRITE;
+		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+		for (i = 0; i < ARRAY_SIZE(params->reserved); i++)
+			params->reserved[i] = 0;
+
 		return 0;
 	}
 
-- 
2.44.0