From nobody Thu Dec 18 07:14:08 2025 Received: from mail-pf1-f196.google.com (mail-pf1-f196.google.com [209.85.210.196]) (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 48599195F22; Thu, 27 Jun 2024 14:24:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.196 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719498264; cv=none; b=aACOKAfBlFHMaQCVEyVgy0paAX9XlroOAV0cBXjM6QhBFKJ5oSQnotKj3WP1h1Bj91+VgYHgwkhCJlNYdfnJDyREzWE7WWSHqjUUjxbMxIQYO51XjTm556a50Xi7Sc9DTxU0kkmHn2WkbCbIuCx/Cw5q9G+U5uSlSEZ2n/mScXY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719498264; c=relaxed/simple; bh=Q2jff5QT5dahZ0NplzuKdapGzNO6RH+dDW7S1GCf5v4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=KJtxu4C/6721T3B5L33/qiuzaMoxSTsqdrrylFWNiOCNx9Mih9aC2fLgKeukM2yNPUXZksHWuFS9FQ5zQWH02rAdsGfYjqPX6ZR1wCnrqfbLvUSJunEe87KigMg4Fh2FjJLO2XiHjbTs7xH2fh3d9pbe//iUpIyWkZpZiVh6WN8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=kNxV92eZ; arc=none smtp.client-ip=209.85.210.196 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kNxV92eZ" Received: by mail-pf1-f196.google.com with SMTP id d2e1a72fcca58-70671ecd334so4096063b3a.0; Thu, 27 Jun 2024 07:24:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719498262; x=1720103062; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=f/eLI45W/ooqVC/MA9zQHUWk1MIJ0qMRX6RqXTFEWV8=; b=kNxV92eZzHtv8FnLNVXDxkpXstN1yuHC5iRPqRxvzkvHRWN2wW6uCUBhIjXtlevCoc +cunYdZVanA2dy4OK5apl5iP0ONnqRXa8bqPFz8G9EmRuNI73UgFg6oS3pz1he6WyYVx 78bZBFzZW4EzvrkAnLhP+0vEgrqWSY6C8oQVpj7iUhdty/etdmlQxp2eqcT3WWs1LxIL 95bc1+VzGbMf73nUc0/6kLyqi22Qn2hZ3GWSD3cHCPdUjUPjHXJDdu9NuSlQsGWfB/hu wjAk7jBwzKemibsoW5I9bKGjzeYOEnGv1J0FFPWRXzbxeSAj5b/0+1KSxwDqCQQey73Y b8IQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719498262; x=1720103062; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=f/eLI45W/ooqVC/MA9zQHUWk1MIJ0qMRX6RqXTFEWV8=; b=LgeBeSUDmcvC7EI47txRoj/lnMrh59N8e1lAdQcFQqeb5FojoeRA4/Hz5TtxpNBrpE nkiDsZ0BMTatVZKjBPYkSmpPStlC0bS6TbZTy38cuWRQetICJhv31Qk25IPSPt5ReB2+ jsTT0D2EBiv3TcDjI9Dohp0iVzVvAVIoGMspEdmNQMItviMk+IdTijb4AcB+cn34IfzZ 9zrwC0df482oJqkP1dxFx5VeJVo7rWFJgr7oSI/tK+4oL2cYs8dtV+gP9+b7Y5HD/AKh QmirmxSD3FqwpTQC9RWYAohF1L2ZLyUa4fnLAwrFjSbj2yrQ/Cjy8RafC883iA7rvNnO NB3g== X-Forwarded-Encrypted: i=1; AJvYcCV+CIFUZGyGniMunruQCllFVlZonz6Hgzyya58zputAbz48inZ/GJ2udLVOGUYBX1HwhFPNO8TftPQ+5nXzFTr/ZcUdKPw6 X-Gm-Message-State: AOJu0YyiigaDret79M3yxzzkXy2rwrykYVMo0GQLQT3XhlICuMrNcpdr JaAAJgot2KIhT9p9oc9Cbrmm/n7QjAKBidKYrilwIy2/JuSp5cjC X-Google-Smtp-Source: AGHT+IFaXa2jgWVK9qwyyMjsUe+VJC/FCmmJqXZaBPd98yzohBR8g9ipU8NKxlQpPhyhZJZYUcyh6Q== X-Received: by 2002:a62:b609:0:b0:706:4889:960d with SMTP id d2e1a72fcca58-70670ee7812mr13853487b3a.16.1719498262365; Thu, 27 Jun 2024 07:24:22 -0700 (PDT) Received: from localhost ([212.107.28.57]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-706b48d0cc0sm1403803b3a.28.2024.06.27.07.24.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Jun 2024 07:24:21 -0700 (PDT) From: Celeste Liu X-Google-Original-From: Celeste Liu To: linux-riscv@lists.infradead.org, =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Cc: linux-kernel@vger.kernel.org, "Dmitry V . Levin" , Guo Ren , Palmer Dabbelt , Emil Renner Berthing , Felix Yan , Ruizhe Pan , Celeste Liu , stable@vger.kernel.org Subject: [PATCH v2] riscv: entry: always initialize regs->a0 to -ENOSYS Date: Thu, 27 Jun 2024 22:23:39 +0800 Message-ID: <20240627142338.5114-2-CoelacanthusHex@gmail.com> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Developer-Signature: v=1; a=openpgp-sha256; l=1313; i=CoelacanthusHex@gmail.com; h=from:subject; bh=Q2jff5QT5dahZ0NplzuKdapGzNO6RH+dDW7S1GCf5v4=; b=owJ4nJvAy8zAJfY4pvNJRPo6U8bTakkMabWlrwIU5LWUEn9rPF/0ydqKUdQyc8m/pJOixUUZJ 13/7OoyCesoZWEQ42KQFVNkEdv59PWy0kcflvGazICZw8oEMoSBi1MAJlLxmeGvREWem4374e3C c6fzxbfX3P67q/yrnX/Nzpn1sZNtBZb0MvzhrGy8bzLFos5JPNT+mve8nBXcHib3J30+45vrduH V0jYeAI3ZS6k= X-Developer-Key: i=CoelacanthusHex@gmail.com; a=openpgp; fpr=892EBC7DC392DFF9C9C03F1D15F4180E73787863 Content-Transfer-Encoding: quoted-printable Otherwise when the tracer changes syscall number to -1, the kernel fails to initialize a0 with -ENOSYS and subsequently fails to return the error code of the failed syscall to userspace. For example, it will break strace syscall tampering. Fixes: 52449c17bdd1 ("riscv: entry: set a0 =3D -ENOSYS only when syscall != =3D -1") Reported-by: "Dmitry V. Levin" Reviewed-by: Bj=C3=B6rn T=C3=B6pel Cc: stable@vger.kernel.org Signed-off-by: Celeste Liu --- arch/riscv/kernel/traps.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 05a16b1f0aee..51ebfd23e007 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -319,6 +319,7 @@ void do_trap_ecall_u(struct pt_regs *regs) =20 regs->epc +=3D 4; regs->orig_a0 =3D regs->a0; + regs->a0 =3D -ENOSYS; =20 riscv_v_vstate_discard(regs); =20 @@ -328,8 +329,7 @@ void do_trap_ecall_u(struct pt_regs *regs) =20 if (syscall >=3D 0 && syscall < NR_syscalls) syscall_handler(regs, syscall); - else if (syscall !=3D -1) - regs->a0 =3D -ENOSYS; + /* * Ultimately, this value will get limited by KSTACK_OFFSET_MAX(), * so the maximum stack offset is 1k bytes (10 bits). --=20 2.45.2