From nobody Fri Dec 19 10:42:18 2025 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAE0619CCF5 for ; Wed, 26 Mar 2025 11:04:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742987096; cv=none; b=q+qB9uBsNuOQoLbWVFkHgaKkLPkto+zgMpgAIwRB4zdzU5YSFU/SOWh6POhDjlzJr7CTfsSeVc57JhZfkslQxeMkzBzZoHTEIfb3WhtX0pEkmUKYoUGLboZPbSRvlX1x6PNPyXsfj4rc99aRSCSZppbYoRDsWcNpxn8B0EPqV+4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742987096; c=relaxed/simple; bh=BzkNRZWNuEiabasgiSZ/Ec4yahGJSxfYCNxx10zT7gA=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=M4vi/If+pTU7USUdjDNwEJ6w4S9EkYDGNz0/ITSgHGab5GRX6WkUTzIfzNrTSN23Ju6r1Ttx1tw4562S7VV7hjDqQ84MNr25IlHxfdRB81VBimpH2tRrSy0OIB33RglTzGZKGF/lfEngK2DsBlt4Hcpnic4B0qZBG98oPZ4pYPI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--keirf.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=1UKvcNzQ; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--keirf.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="1UKvcNzQ" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4394c489babso31123405e9.1 for ; Wed, 26 Mar 2025 04:04:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1742987093; x=1743591893; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=m8s0QIY71zWKro6xSXQRXZSeXe5WAyMtXk+LtoR8l9A=; b=1UKvcNzQ+Ywlq6Kqh+073r1lrhCkOEsQfNvUZ5LKS8j/J7JSYAE+aFiX+BvkubaQ8W Xd+N8DNv5ou6uIcpxOTkQ3Yz+IAvVGx0lp9c7bL10cSk8VQymUHfFeIg+l0iYdCpoL/E psoiaAPX4sX9zgsTJbKD8sLz4moNu/MJP5afvpBUY1w7YSRNtNR28ZczByoQFh1ZotvF BwIBiQK/4zkyR8Lh4vgeQ7tgs81P6GGeE5bwjb278d9Y9D2V8yQu/5BBZ9qgnd7RGq3a c841RKtQGrQrzPMSumHGXTOnD/Hty9AWGUc6d6SeRNMbF17BIjSCFaZwtYycJpleljEH SqiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742987093; x=1743591893; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=m8s0QIY71zWKro6xSXQRXZSeXe5WAyMtXk+LtoR8l9A=; b=d6ZSJNBM4t1TA3lESWSFTGT6oXEk6IHvykwVs+N2Ukp3U/1GVw8dWDxoiBX/g3Cq6L Q+oTysvOehz6IinVx47tvJjl2jU9UNpb76P5u9nDJQ2pQhXkPgzeW8jbttUKvw4jG+Qt 2g8PuchI8U0rKqBgxLY1SsqQzJM9kto50UyVcA+5swxPrEOGXejLqM7QQGMTLYwqp4oX bPADczOC8AV50v7Bg1KLjKXoA6X/eg2tN6/tk7RGMrWDH1Wr0BAfLSPKC+97VgYIXg3L oICCX0oDOfHRq86F+ivH6q7mSZipxCAYifnbIT1mXn9qCwkwMRBvaHCPt5cIwZauHOlT JM3A== X-Forwarded-Encrypted: i=1; AJvYcCUUz5iMJmPY3yZuu3jRNObs2+JM4T7Hr9FBaie4GKXTQzj8HhxVvY1QC5rNUT33bh2Q1wSPNquZEiESFmY=@vger.kernel.org X-Gm-Message-State: AOJu0Yyy62v13EHLpuktGV4L35ANUReKoiwJS5T5OTob70syOuKTZKEH epzkYf+qvcwgl4hhqDFHxtOuy/REaWBGkyT6p6DnB4gd+yyJSMB+G9ucXyv/6Z8+N9M5toxWLw= = X-Google-Smtp-Source: AGHT+IFE7QB78vQyOL/wlLJW8RVd/ZNnGkr6KLJbVri+z1rNmymt2uSjxG1NGSBhHuOotLBvKBi8D1fjsw== X-Received: from wmcq22.prod.google.com ([2002:a05:600c:c116:b0:43d:b30:d2df]) (user=keirf job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:cc6:b0:43d:16a0:d82c with SMTP id 5b1f17b1804b1-43d509e6539mr206451605e9.2.1742987093272; Wed, 26 Mar 2025 04:04:53 -0700 (PDT) Date: Wed, 26 Mar 2025 11:04:47 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Message-ID: <20250326110448.3792396-1-keirf@google.com> Subject: [PATCH v2] arm64: mops: Do not dereference src reg for a set operation From: Keir Fraser To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Keir Fraser , Kristina Martsenko , Catalin Marinas , Mark Rutland , Will Deacon , stable@vger.kernel.org, Marc Zyngier Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The source register is not used for SET* and reading it can result in a UBSAN out-of-bounds array access error, specifically when the MOPS exception is taken from a SET* sequence with XZR (reg 31) as the source. Architecturally this is the only case where a src/dst/size field in the ESR can be reported as 31. Prior to 2de451a329cf662b the code in do_el0_mops() was benign as the use of pt_regs_read_reg() prevented the out-of-bounds access. Fixes: 2de451a329cf662b ("KVM: arm64: Add handler for MOPS exceptions") Cc: Kristina Martsenko Cc: Catalin Marinas Cc: Mark Rutland Cc: Will Deacon Cc: stable@vger.kernel.org Reviewed-by: Marc Zyngier Signed-off-by: Keir Fraser Reviewed-by: Kristina Mart=C5=A1enko --- arch/arm64/include/asm/traps.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index d780d1bd2eac..82cf1f879c61 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -109,10 +109,9 @@ static inline void arm64_mops_reset_regs(struct user_p= t_regs *regs, unsigned lon int dstreg =3D ESR_ELx_MOPS_ISS_DESTREG(esr); int srcreg =3D ESR_ELx_MOPS_ISS_SRCREG(esr); int sizereg =3D ESR_ELx_MOPS_ISS_SIZEREG(esr); - unsigned long dst, src, size; + unsigned long dst, size; =20 dst =3D regs->regs[dstreg]; - src =3D regs->regs[srcreg]; size =3D regs->regs[sizereg]; =20 /* @@ -129,6 +128,7 @@ static inline void arm64_mops_reset_regs(struct user_pt= _regs *regs, unsigned lon } } else { /* CPY* instruction */ + unsigned long src =3D regs->regs[srcreg]; if (!(option_a ^ wrong_option)) { /* Format is from Option B */ if (regs->pstate & PSR_N_BIT) { --=20 2.49.0.395.g12beb8f557-goog