From nobody Fri Dec 19 10:36:46 2025 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 58DC71C8626 for ; Wed, 26 Mar 2025 11:01:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742986899; cv=none; b=pKJXyViJDrRWNw3nH5O+ZWQUAOQ9glAnXTSQw9xsxA+qf21nFVXn5xhP5zsSWV2t1lcXQnDJOI3ZUFTeT58EBGWpKEa5PAE1KVRpGqwWSPOv85NU6jGfcRvq34DFjF0z3OOUfjAd7t2sDYueCc49gbQT9+mz4wgvElZ0HqH6yr0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742986899; c=relaxed/simple; bh=BzkNRZWNuEiabasgiSZ/Ec4yahGJSxfYCNxx10zT7gA=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=dzoT+BMij5xXALqtByolUYWNXFKtcMTIiZNyT9SsI3HYvmbSuDSaPR2XM3BTvE2inopLf9QYj9vTn0E8qdU8aMBVWXeEG/YQLYf/z/kGJSTsEvdS3AYAQaxfwJouY0i+QoSaQ6szmiE3dIuOzxanATImto9PaRIUTXmfqEy0tfg= 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=oTfzV32p; arc=none smtp.client-ip=209.85.128.74 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="oTfzV32p" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-43d4d15058dso48220765e9.0 for ; Wed, 26 Mar 2025 04:01:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1742986896; x=1743591696; 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=oTfzV32pUynTSAxo6xfOT2X4fOFrupk7j/dkEVAwkPViz4XkQjkpdn9G2rAD8veM3G BdXZ3sxmSUjQHf+9zzANGkeVei8mlIdg32VHve7jq4EAPu+/QQTwP5TSs9aI5BgroeeJ BhYlK04m9s824yPt5LoMEFa6EuRKJLE44xIczl3/Kx2NLvGILUZvyg/YCPuHPEUvy0dK 5/uvj0iVFo0lKrayMzTy73RwVK6coOpS2qLpyR5m58T1RzFMCWXaNp6gjZO4dro9CGR1 D8gAwkYKp3By3XKB70cY1W+kaMauJjOU31xdktsVYQp1LYpeFt1gfMOc4RnHqab1BFZr sUVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742986896; x=1743591696; 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=K/QzORwTi7picw3XERma5kYHT9zmJa48poZqjfjYlyeDaad0eSLV+VJlhmhi6aBG7V 2T3qIrMDJsIQp/wUdKOWinh2m155SNuyGj5VRXObJSYPIkCjbMTmfFnYngDXxXO/pQBi cK7Cj18MPXbqpl5OKttMuy1hstd0q1IDPAgO+TzG0byxp/c4mL7+V2GNJVk1LUf+VUrh g9IN2l3UDz2ZcscnSGmm+iS8om5m6xO5bnPyg78OztkTnZciEkP6sm31Dw3OqGd5PB5/ QfjhsoHgumlxDYDLImF2L1TDhjp9zBuQEma3wh9CckxBcp881FvHoQKxOBpMTtu8pu/9 FK5Q== X-Forwarded-Encrypted: i=1; AJvYcCWOWY9rH5foF9/6bMxh5HmJn1vDT9ch5dJcHeKCkjuM5+LTlPIHXVLQeYEP3wWet8peF+kKZOwfSzfHkZg=@vger.kernel.org X-Gm-Message-State: AOJu0YzLVrIyqfgYxy4ruQ8xVlwl2FyFpCNetujBxsRBOAnCQef2P/G4 xvck9N3w9Z+78VTstKxrqELMylAwS0V7jTQ/RL+y/hXVo5ZpcHtQWMF5vgnJOI+lhqqhhK35KA= = X-Google-Smtp-Source: AGHT+IGBA2oNDwoX3vAaJuxLHM6l0qsvxKSEmFmpM5Wmf4mD/taDlkLFT9vj4nHDL4Q52ah1LmKUKhke0w== X-Received: from wrqb8.prod.google.com ([2002:a5d:40c8:0:b0:391:3d79:3021]) (user=keirf job=prod-delivery.src-stubby-dispatcher) by 2002:a5d:5885:0:b0:390:f4f9:8396 with SMTP id ffacd0b85a97d-3997f912d09mr21778026f8f.28.1742986895818; Wed, 26 Mar 2025 04:01:35 -0700 (PDT) Date: Wed, 26 Mar 2025 11:00:58 +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: <20250326110059.3773318-1-keirf@google.com> Subject: [PATCH] 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 Acked-by: Mark Rutland --- 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