From patchwork Thu Aug 22 07:13:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 13772799 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74B6917CA1F; Thu, 22 Aug 2024 07:13:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.17.235.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724310837; cv=none; b=mPsyv3SIngb/JgF8IPryaUzEuHuoxdY952kP77u5A5kwno+JPPX1geFZ0e+PRI69m7XbZf01/P7+JLfbl5BOV8s5E/9wya9tZP8C8InpKn0Fdh/pgL1+DE+9xec4avVfmnBN59fa/uhiry0BnPXPnBzpr04gWyFU3nm7g+A7gpo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724310837; c=relaxed/simple; bh=Tu05MKphwEOYciYKJrZW1zS/5ujWTK6L6L6gDjvRdHs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rFaBdC3/MEVe9VYB6cCOyu/jJfs8406kDtoDFDMElW72JgMih9LHWuIvYjl+T+im08CsBUIYyhurrwQaTWYhnxcR0DCotLoqpMHc3EqZgPlxCHi62qw2zTM5tes3sZi76DMFWuaGd2wqKIYXbWtm4nf6uFunw31rL53HPGvgfqY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu; spf=pass smtp.mailfrom=csgroup.eu; arc=none smtp.client-ip=93.17.235.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4WqDvD04KVz9sST; Thu, 22 Aug 2024 09:13:28 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id U1MT9tMdHKEz; Thu, 22 Aug 2024 09:13:27 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4WqDvC6NsKz9sSH; Thu, 22 Aug 2024 09:13:27 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C8F7C8B763; Thu, 22 Aug 2024 09:13:27 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id Bo_6-yJM0v5v; Thu, 22 Aug 2024 09:13:27 +0200 (CEST) Received: from PO20335.idsi0.si.c-s.fr (PO16920.IDSI0.si.c-s.fr [192.168.232.181]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C10D08B77E; Thu, 22 Aug 2024 09:13:26 +0200 (CEST) From: Christophe Leroy To: Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , "Theodore Ts'o" , "Jason A. Donenfeld" , Arnd Bergmann , Andrew Morton , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Vincenzo Frascino , Shuah Khan Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom Date: Thu, 22 Aug 2024 09:13:13 +0200 Message-ID: <5deb67090b214f0e6eae96b7c406546d1a16f89b.1724309198.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.44.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1724310794; l=1449; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=Tu05MKphwEOYciYKJrZW1zS/5ujWTK6L6L6gDjvRdHs=; b=u0fyVWP390/v2lcPCFKdHXUzbaZAGOJ9fxQFiyRBtDUCKlOBBFypazkoFT3x/4k36OQuZN9O+ 8qHLZBslISeCEi/TEk76Xkmo8/onzIZnJ6KuWgXgE5X334zHCd965Tw X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= 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 Acked-by: Ard Biesheuvel --- 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 +#include #include #include #include @@ -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; }