From: Christophe Leroy christophe.leroy@csgroup.eu
[ Upstream commit b7bad082e113640fc81200ff869e5c2d7a9c29a2 ]
With the current implementation, __cvdso_getrandom_data() calls memset() on certain architectures, which is unexpected in the VDSO.
Rather than providing a memset(), simply rewrite opaque data initialization to avoid memset().
Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu Acked-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Sasha Levin sashal@kernel.org --- lib/vdso/getrandom.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c index bacf19dbb6a11..1281fa3546c20 100644 --- a/lib/vdso/getrandom.c +++ b/lib/vdso/getrandom.c @@ -3,6 +3,7 @@ * Copyright (C) 2022-2024 Jason A. Donenfeld Jason@zx2c4.com. All Rights Reserved. */
+#include <linux/array_size.h> #include <linux/cache.h> #include <linux/kernel.h> #include <linux/time64.h> @@ -73,11 +74,12 @@ __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; + params->size_of_opaque_state = sizeof(*state); + params->mmap_prot = PROT_READ | PROT_WRITE; + params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS; + for (size_t i = 0; i < ARRAY_SIZE(params->reserved); ++i) + params->reserved[i] = 0; return 0; }