From b7bad082e113640fc81200ff869e5c2d7a9c29a2 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 22 Aug 2024 09:13:13 +0200 Subject: [PATCH] random: vDSO: avoid call to out of line memset() 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 Acked-by: Ard Biesheuvel Signed-off-by: Jason A. Donenfeld --- 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 bacf19dbb6a1..1281fa3546c2 100644 --- a/lib/vdso/getrandom.c +++ b/lib/vdso/getrandom.c @@ -3,6 +3,7 @@ * Copyright (C) 2022-2024 Jason A. Donenfeld . All Rights Reserved. */ +#include #include #include #include @@ -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; }